1
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Alameh RT, Rosko MC, Danilov EO, Durand N, Castellano FN. Photophysical and Time-resolved Infrared Properties of Long-Lived Rhenium(I) 4,5-Diazafluorene Tricarbonyl Chromophores. Chemphyschem 2025; 26:e202500008. [PMID: 39933061 PMCID: PMC12058242 DOI: 10.1002/cphc.202500008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2025] [Revised: 02/11/2025] [Accepted: 02/11/2025] [Indexed: 02/13/2025]
Abstract
This report investigates the synthesis, structural characterization, fundamental molecular photophysics, electrochemistry, UV-Vis spectroelectrochemistry, and time-resolved infrared spectroscopic properties of eight [fac-Re(dafR)(CO)3L]0/+ complexes, where R=ethyl [(dedaf); 1, 3, 5, 7] or H [(dafH); 2, 4, 6, 8] and L=Cl- (1, 2), imidazole [(Im); 3, 4], 4-ethylpyridine [(4-Etpy); 5, 6], or pyridine [(py); 7, 8]. Universally, 1-8 yield higher energy photoluminescence (PL) emission bands and higher PL quantum yields (up to 53 %) than the classic 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) ligated Re(I) tricarbonyl complexes. The excited state lifetimes of 1-8 lie between those corresponding to the bpy and phen derivatives, ranging from 120 and 1300 ns at room temperature. Combinations of reductive UV-Vis spectroelectrochemistry, transient absorption spectroscopy, and time-resolved infrared spectroscopy consistently assigned the lowest excited states in 1-8 being of metal-to-ligand charge transfer (MLCT) character. These new ReI MLCT chromophores follow classic energy gap law behavior and possess the characteristics necessary for serving as valuable photosensitizers suitable to energize excited state electron and energy transfer photochemistry.
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Affiliation(s)
- Reem T. Alameh
- Department of ChemistryNorth Carolina State UniversityRaleighNC27695-8204
| | - Michael C. Rosko
- Department of ChemistryNorth Carolina State UniversityRaleighNC27695-8204
| | - Evgeny O. Danilov
- Department of ChemistryNorth Carolina State UniversityRaleighNC27695-8204
| | - Nicolas Durand
- Department of ChemistryNorth Carolina State UniversityRaleighNC27695-8204
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2
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Niazi M, Maisuls I, Mai LA, Schäfer SA, Oster A, Diaz LS, Guldi DM, Doltsinis NL, Strassert CA, Klein A. Conformational Locking of the Geometry in Photoluminescent Cyclometalated N^C^N Ni(II) Complexes. Molecules 2025; 30:1901. [PMID: 40363710 PMCID: PMC12073815 DOI: 10.3390/molecules30091901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2025] [Revised: 04/18/2025] [Accepted: 04/22/2025] [Indexed: 05/15/2025] Open
Abstract
In our research aimed at replacing precious transition metals like platinum with abundant base metals such as nickel for efficient triplet emitters, we synthesized and studied Ni(II) complexes [Ni(LNHR)Cl]. These complexes containing the N^C^N cyclometalating dipyridyl-phenide ligand, equipped with pending H-bonding amine groups (NH(C₆H₅) (LNHPh) and NH(C₆H₅CH₂), ClLNHBn). Molecular structures determined from experimental X-ray diffractometry and density functional theory (DFT) calculations in the ground state showed marked deviation of the Cl- coligand (ancillary ligand) from the ideal planar coordination, with τ4 values of 0.35 and 0.33, respectively, along with hydrogen bonding interactions of the ligand NH function with the Cl- coligand. The complexes exhibit long-wavelength absorption bands at approximately 425 nm in solution, with the experimental spectra being accurately reproduced through time-dependent density functional theory (TD-DFT) calculations. Vibrationally structured emission profiles and steady-state photoluminescence quantum yields of 30% for [Ni(LNHPh)Cl] and 40% for [Ni(LNHBn)Cl] (along with dual excited state lifetimes in the ns and in the ms range) were found in frozen 2-methyl-tetrahydrofuran (2MeTHF) glassy matrices at 77 K. Furthermore, within a poly(methyl methacrylate) matrix, the complexes showed emission bands centered at around 550 nm within a temperature range from 6 K to 300 K with lifetimes similar to 77 K. Based on TD-DFT potential scans along the metal-ligand (Ni-N) coordinate, we found that in a rigid environment that restricts the geometry to the Franck-Condon region, either the triplet T5 or the singlet S4 state could contribute to the photoluminescence.
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Affiliation(s)
- Maryam Niazi
- Department of Chemistry and Biochemistry, Institute for Inorganic and Materials Chemistry, Faculty for Mathematics and Natural Sciences, University of Cologne, Greinstraße 6, D-50939 Köln, Germany; (M.N.); (S.A.S.)
| | - Iván Maisuls
- Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 28/30, D-48149 Münster, Germany;
- CiMIC, CeNTech, Heisenbergstraße 11, D-48149 Münster, Germany
| | - Lukas A. Mai
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, D-91058 Erlangen, Germany; (L.A.M.); (L.S.D.); (D.M.G.)
| | - Sascha A. Schäfer
- Department of Chemistry and Biochemistry, Institute for Inorganic and Materials Chemistry, Faculty for Mathematics and Natural Sciences, University of Cologne, Greinstraße 6, D-50939 Köln, Germany; (M.N.); (S.A.S.)
| | - Alex Oster
- Institut für Festkörpertheorie and Center for Multiscale Theory and Computation, Universität Münster, Wilhelm-Klemm-Straße 10, D-48149 Münster, Germany;
| | - Lukas Santiago Diaz
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, D-91058 Erlangen, Germany; (L.A.M.); (L.S.D.); (D.M.G.)
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, D-91058 Erlangen, Germany; (L.A.M.); (L.S.D.); (D.M.G.)
| | - Nikos L. Doltsinis
- Institut für Festkörpertheorie and Center for Multiscale Theory and Computation, Universität Münster, Wilhelm-Klemm-Straße 10, D-48149 Münster, Germany;
| | - Cristian A. Strassert
- Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 28/30, D-48149 Münster, Germany;
- CiMIC, CeNTech, Heisenbergstraße 11, D-48149 Münster, Germany
| | - Axel Klein
- Department of Chemistry and Biochemistry, Institute for Inorganic and Materials Chemistry, Faculty for Mathematics and Natural Sciences, University of Cologne, Greinstraße 6, D-50939 Köln, Germany; (M.N.); (S.A.S.)
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3
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Anghileri L, Baunis H, Bena AR, Giannoudis C, Burke JH, Reischauer S, Merschjann C, Wallick RF, Al Said T, Adams CE, Simionato G, Kovalenko S, Dell’Amico L, van der Veen RM, Pieber B. Evidence for a Unifying Ni I/Ni III Mechanism in Light-Mediated Cross-Coupling Catalysis. J Am Chem Soc 2025; 147:13169-13179. [PMID: 40211781 PMCID: PMC12022987 DOI: 10.1021/jacs.4c16050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2024] [Revised: 03/25/2025] [Accepted: 03/28/2025] [Indexed: 04/24/2025]
Abstract
Advances in nickel catalysis have significantly broadened the synthetic chemists' toolbox, particularly through methodologies leveraging paramagnetic nickel species via photoredox catalysis or electrochemistry. Key to these reactions is the oxidation state modulation of nickel via single-electron transfer events. Recent mechanistic studies indicate that C(sp2)-heteroatom bond formations proceed through NiI/NiIII cycles. Related C(sp2)-C(sp3) cross-couplings operate via the photocatalytic generation of C-centered radicals and a catalytic cycle that involves Ni0, NiI, and NiIII species. Here, we show that light-mediated nickel-catalyzed C(sp2)-C(sp3) bond formations can be carried out without using exogenous photoredox catalysts but with a photoactive ligand. In a pursuit of expanding the scope of C(sp2)-heteroatom couplings using donor-acceptor ligands, we identified a photoactive nickel complex capable of catalyzing cross-couplings between aryl halides and benzyltrifluoroborate salts. Mechanistic investigations provide evidence that transmetalation between a photochemically generated NiI species and the organoboron compound is the key catalytic step in a NiI/NiIII catalytic cycle under these conditions.
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Affiliation(s)
- Lucia Anghileri
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces (MPICI), Am Mühlenberg 1, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, Berlin 14195, Germany
| | - Haralds Baunis
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces (MPICI), Am Mühlenberg 1, Potsdam 14476, Germany
| | - Aleksander R. Bena
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces (MPICI), Am Mühlenberg 1, Potsdam 14476, Germany
| | - Christos Giannoudis
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces (MPICI), Am Mühlenberg 1, Potsdam 14476, Germany
| | - John H. Burke
- Department
of Chemistry, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Susanne Reischauer
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces (MPICI), Am Mühlenberg 1, Potsdam 14476, Germany
| | - Christoph Merschjann
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Rachel F. Wallick
- Department
of Chemistry, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Tarek Al Said
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Callum E. Adams
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
| | - Gianluca Simionato
- Department
of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, Padova 35131, Italy
| | - Sergey Kovalenko
- Department
of Chemistry, Humboldt-Universität
zu Berlin, Brook-Taylor-Str.
2, Berlin 12489, Germany
| | - Luca Dell’Amico
- Department
of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, Padova 35131, Italy
| | - Renske M. van der Veen
- Department
of Chemistry, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
- Institute
of Optics and Atomic Physics, Technische
Universität Berlin, Hardenbergstraße 36, Berlin 10623, Germany
| | - Bartholomäus Pieber
- Institute
of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces (MPICI), Am Mühlenberg 1, Potsdam 14476, Germany
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4
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Burton ST, Lee G, Moore CE, Sevov CS, Turro C. Cyclometallated Co(III) Complexes with Lowest-Energy Charge Transfer Excited States Accessible with Visible Light. J Am Chem Soc 2025; 147:13315-13327. [PMID: 40207665 DOI: 10.1021/jacs.4c18299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2025]
Abstract
The Co(III) complexes, cis-[Co(ppy)2(L)]PF6, where ppy = 2-phenylpyridine and L = bpy (2,2'-bipyridine; 1), phen (1,10-phenanthroline; 2), and DAP (1,12-diazaperylene; 3), are reported and their photophysical properties were investigated to evaluate their potential as sensitizers for applications that include solar energy conversion schemes and photoredox catalysis. Calculations show that cyclometallation in the cis-[Co(ppy)2(L)]PF6 series affords strong Co(dπ)/ppy(π) orbital interactions that result in a Co/ppy(π*) highest occupied molecular orbital (HOMO) and a lowest unoccupied molecular orbital (LUMO) localized on the diimine ligand, L(π*). Complexes 1-3 exhibit relatively invariant oxidation potentials, whereas the reduction event is dependent on the identity of the diimine ligand, L, consistent with the theoretical predictions. For 3 a broad Co/ppy(π*) → L(π*) metal/ligand-to-ligand charge transfer (ML-LCT) absorption band is observed in CH3CN with a maxima at 507 nm, extending beyond 600 nm. Upon excitation of the 1ML-LCT transition, transient absorption features consistent with the population of a 3ML-LCT excited state with lifetimes, τ, of 3.0 ps, 4.6 and 42 ps for 1, 2 and 3 in CH3CN respectively are observed. Upon irradiation with 505 nm, 3 is able to reduce methyl viologen (MV2+), an electron acceptor commonly in photocatalytic schemes. To our knowledge, 3 represents the first heteroleptic molecular Co(III) complex that combines cyclometallation with a diimine ligand with lowest-lying metal-to-ligand charge transfer excited states able to undergo photoinduced charge transfer with low-energy green light. As such, the structural design of 3 represents an important step toward d6 photosensitizers based on earth abundant metals.
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Affiliation(s)
- Spencer T Burton
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43214, United States
| | - Gyunhee Lee
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43214, United States
| | - Curtis E Moore
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43214, United States
| | - Christo S Sevov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43214, United States
| | - Claudia Turro
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43214, United States
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5
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Ghodrati N, Eckert S, Fondell M, Scherz A, Föhlisch A, Van Kuiken BE. Identification of metal-centered excited states in Cr(iii) complexes with time-resolved L-edge X-ray spectroscopy. Chem Sci 2025; 16:6307-6316. [PMID: 40078607 PMCID: PMC11895842 DOI: 10.1039/d4sc07625g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2024] [Accepted: 02/25/2025] [Indexed: 03/14/2025] Open
Abstract
New coordination complexes of 3d metals that possess photoactive metal-centered (MC) excited states are promising targets for optical applications and photocatalysis. Ultrafast spectroscopy plays an important role in elucidating the photophysical mechanisms that underlie photochemical activity. However, it can be difficult to assign transient signals to specific electronic excited states and mechanistic information is often inferred from kinetics. Here it is demonstrated that 3d L-edge X-ray absorption spectroscopy is highly selective for MC excited states. This is accomplished by probing the 2E spin-flip excited state in Cr(acac)3 using synchrotron-based picosecond time-resolved XAS in solution. This excited state of Cr(iii) has the property that its potential is nested with the ground state, which allows for the assessment of purely electronic changes upon excited state formation. Combining the measurements with ligand field and ab initio theory shows that the observed spectral changes between the 4A2 ground state and 2E excited state are due to an intensity redistribution among the core-excited multiplets. Extrapolating these results to higher-lying MC excited states predicts that Cr L3-edge XAS can distinguish two states separated by ∼0.1 eV despite the L3-edge resolution being limited by the 0.27 eV lifetime width of the 2p core-hole. This highlights the potential of L-edge XAS as a sub-natural linewidth probe of electronic state identity.
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Affiliation(s)
| | - Sebastian Eckert
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialen and Energie GmbH 12489 Berlin Germany
| | - Mattis Fondell
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialen and Energie GmbH 12489 Berlin Germany
| | | | - Alexander Föhlisch
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialen and Energie GmbH 12489 Berlin Germany
- Institut für Physik und Astronomie, Universität Potsdam 14476 Potsdam Germany
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6
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Morselli G, Reber C, Wenger OS. Molecular Design Principles for Photoactive Transition Metal Complexes: A Guide for "Photo-Motivated" Chemists. J Am Chem Soc 2025; 147:11608-11624. [PMID: 40147007 PMCID: PMC11987026 DOI: 10.1021/jacs.5c02096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2025] [Revised: 03/10/2025] [Accepted: 03/11/2025] [Indexed: 03/29/2025]
Abstract
Luminescence and photochemistry involve electronically excited states that are inherently unstable and therefore spontaneously decay to electronic ground states, in most cases by nonradiative energy release that generates heat. This energy dissipation can occur on a time scale of 100 fs (∼10-13 s) and usually needs to be slowed down to at least the nanosecond (∼10-9 s) time scale for luminescence and intermolecular photochemistry to occur. This is a challenging task with many different factors to consider. An alternative emerging strategy is to target dissociative excited states that lead to metal-ligand bond homolysis on the subnanosecond time scale to access synthetically useful radicals. Based on a thorough review at the most recent advances in the field, this article aims to provide a concise guide to obtaining luminescent and photochemically useful coordination compounds with d-block elements. We hope to encourage "photo-motivated" chemists who have been reluctant to apply their synthetic and other knowledge to photophysics and photochemistry, and we intend to stimulate new approaches to the synthetic control of excited state behavior.
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Affiliation(s)
- Giacomo Morselli
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Christian Reber
- Département
de chimie, Université de Montréal, Montréal QC H3C
3J7, Canada
| | - Oliver S. Wenger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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7
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Oku N, Saeki R, Doi Y, Yamazaki K, Miura T. 1,2-Acylcyanation of Styrenes by Photoinduced Nickel Catalysis to Generate Acyl Radicals from Acyl Fluorides. Org Lett 2025; 27:3361-3367. [PMID: 40131824 DOI: 10.1021/acs.orglett.5c00761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2025]
Abstract
We report herein a photoinduced nickel-catalyzed 1,2-acylcyanation of styrenes with acyl fluorides and trimethylsilyl cyanide (TMSCN). Nickel(II) acyl complexes, formed from nickel(0) complexes and acyl fluorides, are photoexcited to generate acyl radicals via a ligand-to-metal charge transfer (LMCT) process. This transformation proceeds under mild conditions and thus can be applied to the late-stage functionalization (LSF) of natural product derivatives. Synthetic derivatizations show the utility of the products. The preparation of aza-DIPYs is also demonstrated.
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Affiliation(s)
- Naoki Oku
- Division of Applied Chemistry, Okayama University, Tsushimanaka, Okayama 700-8530, Japan
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Reo Saeki
- Division of Applied Chemistry, Okayama University, Tsushimanaka, Okayama 700-8530, Japan
| | - Yuriko Doi
- Division of Applied Chemistry, Okayama University, Tsushimanaka, Okayama 700-8530, Japan
| | - Ken Yamazaki
- Division of Applied Chemistry, Okayama University, Tsushimanaka, Okayama 700-8530, Japan
| | - Tomoya Miura
- Division of Applied Chemistry, Okayama University, Tsushimanaka, Okayama 700-8530, Japan
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8
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Chang Q, Li Q, Deng YH, Sun TY, Wu YD, Wang L. Nickel catalyzed C-N coupling of haloarenes with B 2N 4 reagents. Nat Commun 2025; 16:3202. [PMID: 40180918 PMCID: PMC11968942 DOI: 10.1038/s41467-025-58438-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Accepted: 03/20/2025] [Indexed: 04/05/2025] Open
Abstract
Carbon-heteroatom bond (especially for C-N bond) formation through nickel catalysis has seen significant development. Well-established Ni(0)/Ni(II) redox cycle and photoinduced Ni(I)/Ni(III) redox cycle have been the dominant mechanisms. We report a thermally driven Ni-catalyzed method for C-N bond formation between haloarenes and B2N4 reagents, yielding N,N-dialkylaniline derivatives in good to excellent yields with broad functional group tolerance under base-free conditions. The catalytic protocol is useful for base-sensitive structures and late-stage modifications of complex molecules. Detailed mechanistic studies and density functional theory (DFT) calculations indicate that a Ni(I)/Ni(III) redox cycle is preferred in the C-N coupling process, and B2N4 reagent serves both as a single electron transfer donor and a N,N-dialkylation source.
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Affiliation(s)
- Qianqian Chang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, P. R. China
| | - Qini Li
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, P. R. China
| | - Yi-Hui Deng
- Key Laboratory of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Shenzhen Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong, P. R. China
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, China
| | - Tian-Yu Sun
- Key Laboratory of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Shenzhen Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong, P. R. China.
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, China.
| | - Yun-Dong Wu
- Key Laboratory of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Shenzhen Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong, P. R. China.
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, China.
- College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
| | - Leifeng Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, P. R. China.
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9
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Sakizadeh JD, Weiss R, Scholes GD, Kudisch B. Ultrafast Spectroscopy and Dynamics of Photoredox Catalysis. Annu Rev Phys Chem 2025; 76:203-229. [PMID: 39899834 DOI: 10.1146/annurev-physchem-082423-013952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2025]
Abstract
Photoredox catalysis has emerged as a powerful platform for chemical synthesis, utilizing chromophore excited states as selective energy stores to surmount chemical activation barriers toward making desirable products. Developments in this field have pushed synthetic chemists to design and discover new photocatalysts with novel and impactful photoreactivity but also with uncharacterized excited states and only an approximate mechanistic understanding. This review highlights specific instances in which ultrafast spectroscopies dissected the photophysical and photochemical dynamics of new classes of photoredox catalysts and their photochemical reactions. After briefly introducing the photophysical processes and ultrafast spectroscopic methods central to this topic, the review describes selected recent examples that evoke distinct classes of photoredox catalysts with demonstrated synthetic utility and ultrafast spectroscopic characterization. This review cements the significant role of ultrafast spectroscopy in modern photocatalyzed organic transformations and institutionalizes the developing intersection of synthetic organic chemistry and physical chemistry.
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Affiliation(s)
- John D Sakizadeh
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA
| | - Rachel Weiss
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida, USA;
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA
| | - Bryan Kudisch
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida, USA;
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10
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Leung JJN, Bae DY, Moshood Y, Mirica LM. C-C and C-O bond formation reactivity of nickel complexes supported by the pyridinophane MeN3C ligand. Dalton Trans 2025; 54:5286-5292. [PMID: 40029120 DOI: 10.1039/d5dt00135h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2025]
Abstract
The pyridinophane ligands RN3CX (X = H, Br) are well-established scaffolds that facilitate and stabilize nickel oxidative addition complexes to the proximal C(aryl)-X bond. In this study, we report the synthesis, detailed characterization, and reactivity of a series of NiII and NiIII complexes supported by the MeN3CX ligand. Our findings demonstrate that NiII complexes can be oxidized to readily yield well-defined NiIII species. Excitingly, the Ni-disolvento complexes exhibit catalytic trifluoroethoxylation to generate the C-O coupled product. In addition, the NiIII-halide complex undergoes transmetallation with a Grignard reagent and subsequent C-C reductive elimination, while the β-hydride elimination side reaction is suppressed, outperforming its NiII analogue.
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Affiliation(s)
- Joshua Ji-Nung Leung
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois, 61801, USA.
| | - Dae Young Bae
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois, 61801, USA.
| | - Yusuff Moshood
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois, 61801, USA.
| | - Liviu M Mirica
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois, 61801, USA.
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11
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Juliá F. Catalysis in the Excited State: Bringing Innate Transition Metal Photochemistry into Play. ACS Catal 2025; 15:4665-4680. [PMID: 40144674 PMCID: PMC11934144 DOI: 10.1021/acscatal.4c07962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2024] [Revised: 02/11/2025] [Accepted: 02/11/2025] [Indexed: 03/28/2025]
Abstract
Transition metal catalysis is an indispensable tool for organic synthesis that has been harnessed, modulated, and perfected for many decades by careful selection of metal centers and ligands, giving rise to synthetic methods with unparalleled efficiency and chemoselectivity. Recent developments have demonstrated how light irradiation can also be recruited as a powerful tool to dramatically alter the outcome of catalytic reactions, providing access to innovative pathways with remarkable synthetic potential. In this context, the adoption of photochemical conditions as a mainstream strategy to drive organic reactions has unveiled exciting opportunities to exploit the rich excited-state framework of transition metals for catalytic applications. This Perspective examines advances in the application of transition metal complexes as standalone photocatalysts, exploiting the innate reactivity of their excited states beyond their common use as photoredox catalysts. An account of relevant examples is dissected to provide a discussion on the electronic reorganization, the orbitals involved, and the associated reactivity of different types of excited states. This analysis aims to provide practitioners with fundamental principles and guiding strategies to understand, design, and apply light-activation strategies to homogeneous transition metal catalysis for organic synthesis.
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Affiliation(s)
- Fabio Juliá
- Facultad de Química,
Centro de Investigación Multidisciplinar Pleiades-Vitalis, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
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12
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Tong X, Ren L, Wang Y, Zhang D, Li J, Xia C. Visible-Light-Induced Tandem Nickel-Catalyzed Heck Cyclization/Self-Promoted [2+2] Intermolecular Cycloaddition. Org Lett 2025; 27:2775-2781. [PMID: 40071539 DOI: 10.1021/acs.orglett.5c00611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2025]
Abstract
Visible-light-induced transition metal (TM) catalysis has emerged as a new paradigm to discover unprecedented transformations. The reported nickel species as TM photocatalysts are mainly involved in the homolysis of Ni(II) complex or alkyl halide activation. Herein, we describe that the photoexcited nickel species could facilitate Heck cyclization by accelerating the anti-β-hydride elimination. Meanwhile, a tandem visible-light-induced substrate self-promoted intermolecular [2+2] photocycloaddition without the assistance of additional photocatalysts was discovered.
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Affiliation(s)
- Xiaogang Tong
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development of Natural Products, School of Pharmacy, Yunnan University, Kunming 650500, China
| | - Linlin Ren
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development of Natural Products, School of Pharmacy, Yunnan University, Kunming 650500, China
| | - Yonggong Wang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development of Natural Products, School of Pharmacy, Yunnan University, Kunming 650500, China
| | - Derun Zhang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development of Natural Products, School of Pharmacy, Yunnan University, Kunming 650500, China
- Southwest United Graduate School, Kunming 650092, China
| | - Jianwei Li
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development of Natural Products, School of Pharmacy, Yunnan University, Kunming 650500, China
| | - Chengfeng Xia
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development of Natural Products, School of Pharmacy, Yunnan University, Kunming 650500, China
- Southwest United Graduate School, Kunming 650092, China
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13
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Thillman A, Kill EC, Erickson AN, Wang D. Visible-Light-Driven Catalytic Dehalogenation of Trichloroacetic Acid and α-Halocarbonyl Compounds: Multiple Roles of Copper. ACS Catal 2025; 15:3873-3881. [PMID: 40078408 PMCID: PMC11894595 DOI: 10.1021/acscatal.4c07845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2024] [Revised: 01/16/2025] [Accepted: 01/21/2025] [Indexed: 03/14/2025]
Abstract
Herein, we report the reaction development and mechanistic studies of visible-light-driven Cu-catalyzed dechlorination of trichloroacetic acid for the highly selective formation of monochloroacetic acid. Visible-light-driven transition metal catalysis via an inner-sphere pathway features the dual roles of transition metal species in photoexcitation and substrate activation steps, and a detailed mechanistic understanding of their roles is crucial for the further development of light-driven catalysis. This catalytic method, which features environmentally desired ascorbic acid as the hydrogen atom source and water/ethanol as the solvent, can be further applied to the dehalogenation of a variety of halocarboxylic acids and amides. Spectroscopic, X-ray crystallographic, and kinetic studies have revealed the detailed mechanism of the roles of copper in photoexcitation, thermal activation of the first C-Cl bond, and excited-state activation of the second C-Cl bond via excited-state chlorine atom transfer.
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Affiliation(s)
- Abigail
J. Thillman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Erin C. Kill
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Alexander N. Erickson
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Dian Wang
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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14
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Lim H, Yang X, Larsen CB, Ledbetter K, Zoric MR, Raj SL, Kumar G, Powers-Riggs N, Hoffmann MC, Chollet M, Gee LB, van Driel TB, Alonso-Mori R, Kabanova V, Kahraman A, Johnson PJM, Cirelli C, Bacellar C, Gaffney KJ, Li X, Cordones AA. Excited State Covalency, Dynamics, and Photochemistry of Square Planar Ni-Thiolate Complexes Revealed by Ultrafast X-ray Absorption. J Am Chem Soc 2025; 147:7496-7506. [PMID: 39993950 DOI: 10.1021/jacs.4c16212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2025]
Abstract
Highly covalent Ni bis(dithiolene) and related complexes provide an ideal platform for investigating the effects of metal-ligand orbital hybridization on excited state character and dynamics. In particular, we focus on the ligand field excited states that dominate the photophysics of first-row transition metal complexes. We investigate if they can be significantly delocalized off the metal center, possibly yielding photochemical reactivity more similar to charge transfer excited states than metal-centered ligand field excited states. Here, [Ni(mpo)2] (mpo = 2-mercaptopyridine-N-oxide) provides a representative example for the larger chemical class and is an active electro- and photocatalyst for proton reduction. A detailed characterization of the excited state electronic structure, dynamics, and photochemistry of [Ni(mpo)2] is presented based on ultrafast transient X-ray absorption spectroscopy at the Ni and S 1s core absorption K-edges. By comparing the ultrafast Ni K-edge absorption to ab initio calculations, we identify an excited state relaxation mechanism where an initial ligand-to-metal charge transfer excitation results in both excited state electron transfer (generating a catalytically relevant reduced photoproduct [Ni(mpo)2]-) and relaxation to a pseudotetrahedral triplet ligand field excited state. From the ultrafast S K-edge absorption, the ligand field excited state is found to be highly delocalized onto the thiolate ligands, and a tetrahedral structural distortion is shown to substantially influence the degree of delocalization. The results identify a significant structural coordinate to target when aiming to control the excited state covalency in square planar complexes.
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Affiliation(s)
- Hyeongtaek Lim
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Xinzheng Yang
- University of Washington, Seattle, Washington 98195, United States
| | - Christopher B Larsen
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Kathryn Ledbetter
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Marija R Zoric
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Sumana L Raj
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Gaurav Kumar
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Natalia Powers-Riggs
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Matthias C Hoffmann
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Matthieu Chollet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Leland B Gee
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Tim B van Driel
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Roberto Alonso-Mori
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | | | | | | | | | | | - Kelly J Gaffney
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Xiaosong Li
- University of Washington, Seattle, Washington 98195, United States
| | - Amy A Cordones
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
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15
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Fortier L, Lefebvre C, Hoffmann N. Red light excitation: illuminating photocatalysis in a new spectrum. Beilstein J Org Chem 2025; 21:296-326. [PMID: 39931681 PMCID: PMC11809576 DOI: 10.3762/bjoc.21.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2024] [Accepted: 01/31/2025] [Indexed: 02/13/2025] Open
Abstract
Red-light-activated photocatalysis has become a powerful approach for achieving sustainable chemical transformations, combining high efficiency with energy-saving, mild conditions. By harnessing the deeper penetration and selectivity of red and near-infrared light, this method minimizes the side reactions typical of higher-energy sources, making it particularly suited for large-scale applications. Recent advances highlight the unique advantages of both metal-based and metal-free catalysts under red-light irradiation, broadening the range of possible reactions, from selective oxidations to complex polymerizations. In biological contexts, red-light photocatalysis enables innovative applications in phototherapy and controlled drug release, exploiting its tissue penetration and low cytotoxicity. Together, these developments underscore the versatility and impact of red-light photocatalysis, positioning it as a cornerstone of green organic chemistry with significant potential in synthetic and biomedical fields.
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Affiliation(s)
- Lucas Fortier
- Unité de Catalyse et de Chimie du Solide (UCCS), University of Lille, CNRS, University of Artois UMR 8181, Avenue Mendeleiev, 59655 Villeneuve d’Ascq CEDEX, France
| | - Corentin Lefebvre
- Laboratory of Glycochemistry and Agroressources of Amiens (LG2A), University of Picardie Jules Verne UR 7378, 10 rue Baudelocque, 80000 Amiens, France
| | - Norbert Hoffmann
- Institute of Physics and Chemistry of Materials of Strasbourg (IPCMS), University of Strasbourg UMR 7504, 23 rue du Loess, BP 43, 67034 Strasbourg CEDEX 2, France
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16
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Rodriguez-Lugo RE, Sander J, Dietzmann S, Rittner T, Rückel J, Landaeta VR, Park J, Nuernberger P, Baik MH, Wolf R. Mechanistic insights into the visible-light-driven O-arylation of carboxylic acids catalyzed by xanthine-based nickel complexes. Chem Sci 2025; 16:2751-2762. [PMID: 39810999 PMCID: PMC11726235 DOI: 10.1039/d4sc04257c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Accepted: 12/25/2024] [Indexed: 01/16/2025] Open
Abstract
We present a photocatalytic protocol for the O-arylation of carboxylic acids using nickel complexes bearing C8-pyridyl xanthines. Our studies suggest that the underlying mechanism operates independently of external photosensitizers. Stoichiometric experiments and crystallographic studies characterize the catalytically relevant Ni complexes. Spectroscopic and computational investigations propose a thermally controlled Ni(i)/Ni(iii) cycle followed by a photochemical regeneration of Ni(i) species. Furthermore, the pathways leading to the hydrodehalogenation of aryl halides, the comproportionation of Ni(i) and Ni(iii) species, the dimerization of Ni(i) intermediates and the influence of the counter ion on the cross-coupling reaction are unveiled. These investigations offer a comprehensive mechanistic understanding of the photocatalytic cross-coupling reaction catalyzed by a single Ni species and highlight key aspects of nickel-catalyzed metallaphotoredox reactions.
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Affiliation(s)
| | - Joan Sander
- University of Regensburg, Institute of Inorganic Chemistry 93040 Regensburg Germany
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
| | - Simon Dietzmann
- University of Regensburg, Institute of Inorganic Chemistry 93040 Regensburg Germany
| | - Thomas Rittner
- University of Regensburg, Institute of Physical and Theoretical Chemistry 93040 Regensburg Germany
| | - Jannes Rückel
- University of Regensburg, Institute of Inorganic Chemistry 93040 Regensburg Germany
| | - Vanessa R Landaeta
- University of Regensburg, Institute of Inorganic Chemistry 93040 Regensburg Germany
| | - Jiyong Park
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 43141 Republic of Korea
| | - Patrick Nuernberger
- University of Regensburg, Institute of Physical and Theoretical Chemistry 93040 Regensburg Germany
| | - Mu-Hyun Baik
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) Daejeon 34141 Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 43141 Republic of Korea
| | - Robert Wolf
- University of Regensburg, Institute of Inorganic Chemistry 93040 Regensburg Germany
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17
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Teixeira R, Waldron Clarke TH, Love A, Sun XZ, Kayal S, George MW. Scale-Up of Continuous Metallaphotoredox Catalyzed C-O Coupling to a 10 kg-Scale Using Small Footprint Photochemical Taylor Vortex Flow Reactors. Org Process Res Dev 2025; 29:34-47. [PMID: 39839539 PMCID: PMC11744928 DOI: 10.1021/acs.oprd.4c00262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 11/08/2024] [Accepted: 11/19/2024] [Indexed: 01/23/2025]
Abstract
We report the development and optimization of a scalable flow process for metallaphotoredox (Ir/Ni) C-O coupling, a mild and efficient approach for forming alkyl-aryl ethers, a common motif in medicinal and process chemistry settings. Time-resolved infrared spectroscopy (TRIR) highlighted the amine as the major quencher of the photocatalyst triplet excited state, along with the formation of an Ir(II) species that, in the presence of the Ni cocatalyst, has its lifetime shortened, suggesting reductive quenching of Ir(III)*, followed by reoxidation facilitated by the Ni cocatalyst. TRIR and batch reaction screening was used to develop conditions transferrable to flow, and many processing benefits of performing the reaction in flow were then demonstrated using a simple to construct/operate, small-footprint FEP coil flow reactor, including short (<10 min) space times and reduced catalyst loadings (down to 0.1 mol % Ir, 1 mol % Ni) while retaining good yield/conversion. Scalability was demonstrated by increasing the length or diameter of the FEP coil flow reactor tubing, however, due to suspected mass transfer/mixing limitations, the yield decreased upon scale-up in some cases. Therefore, we applied a modified version of our previously reported photochemical Taylor Vortex Flow Reactor (PhotoVortex), where Taylor vortices and a short-irradiated path length allow photochemical reactions to be performed efficiently via excellent mixing. In a small PhotoVortex (8 mL irradiated volume), we have demonstrated projected productivities around 1 kg day-1 and >10 kg day-1 in a large PhotoVortex (185 mL irradiated volume) with good product yields (>90%) and low catalyst loadings (0.1 to 0.5 mol % of [Ir{dF(CF3)ppy}2dtbbpy]PF6), enabled by excellent mixing ensuring sufficient mass transfer between short-lived photoexcited and other transient species.
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Affiliation(s)
| | | | - Ashley Love
- School of Chemistry, The University
of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Xue-Zhong Sun
- School of Chemistry, The University
of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Surajit Kayal
- School of Chemistry, The University
of Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Michael W. George
- School of Chemistry, The University
of Nottingham, University Park, Nottingham NG7 2RD, U.K.
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18
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Gao M, To W, Tong GSM, Du L, Low K, Tang Z, Lu W, Che C. Dinuclear Cyclometalated Pincer Nickel(II) Complexes with Metal-Metal-to-Ligand Charge Transfer Excited States and Near-Infrared Emission. Angew Chem Int Ed Engl 2025; 64:e202414411. [PMID: 39320051 PMCID: PMC11720376 DOI: 10.1002/anie.202414411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2024] [Revised: 09/04/2024] [Accepted: 09/25/2024] [Indexed: 09/26/2024]
Abstract
Facile non-radiative decay of low-lying metal-centered (MC) dd excited states has been well documented to pose a significant obstacle to the development of phosphorescent NiII complexes due to substantial structural distortions between the dd excited state and the ground state. Herein, we prepared a series of dinuclear Ni2 II,II complexes by using strong σ-donating carbene-phenyl-carbene (CNHC Cphenyl CNHC) pincer ligands, and prepared their dinuclear Pt2 II,II and Pd2 II,II analogues. Dinuclear Ni2 II,II complexes bridged by formamidinate/α-carbolinato ligand exhibit short Ni-Ni distances of 2.947-3.054 Å and singlet metal-metal-to-ligand charge transfer (1MMLCT) transitions at 500-550 nm. Their 1MMLCT absorption energies are red-shifted relative to the Pt2 II,II and Pd2 II,II analogues at ~450 nm and ≤420 nm respectively. One-electron oxidation of these Ni2 II,II complexes produces valence-trapped dinuclear Ni2 II,III species, which are characterized by EPR spectroscopy. Upon photoexcitation, these Ni2 II,II complexes display phosphorescence (τ=2.6-8.6 μs) in the NIR (800-1400 nm) spectral region in 2-MeTHF and in the solid state at 77 K, which is insensitive to π-conjugation of the coordinated [CNHC Cphenyl CNHC] ligand. Combined with DFT calculations, the NIR emission is assigned to originate from the 3dd excited state. Studies have found that the dinuclear Ni2 II,II complex can sensitize the formation of singlet oxygen and catalyze the oxidation of cyclo-dienes under light irradiation.
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Affiliation(s)
- Mengyue Gao
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
| | - Wai‐Pong To
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
| | - Glenna So Ming Tong
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
| | - Lili Du
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
| | - Kam‐Hung Low
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
| | - Zhou Tang
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
- Laboratory for Synthetic Chemistry and Chemical Biology LimitedUnits 1503-1511, 15/F, Building 17W, Hong Kong Science Park, New TerritoriesHong KongP. R. China
| | - Wei Lu
- Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong518055P. R. China
| | - Chi‐Ming Che
- Department of ChemistryState Key Laboratory of Synthetic ChemistryCAS-HKU Joint Laboratory on New MaterialsThe University of Hong KongPokfulam RoadHong KongP. R. China
- HKU Shenzhen Institute of Research and InnovationShenzhenGuangdong518057P. R. China
- Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong518055P. R. China
- Laboratory for Synthetic Chemistry and Chemical Biology LimitedUnits 1503-1511, 15/F, Building 17W, Hong Kong Science Park, New TerritoriesHong KongP. R. China
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19
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Abstract
With the advent of photoredox catalysis, new synthetic paradigms have been established with many novel transformations being achieved. Nevertheless, modern photoredox chemistry has several drawbacks, namely, deficiencies in reaction efficiency and scalability. Furthermore, wavelengths of light in excess of the energy required for a chemical reaction are often used. In this Review, we document recent developments of low-energy light-absorbing catalysts and their cognate photochemical methods, advantageously mitigating off-cycle photochemical reactivity of excited-state species in the reaction mixture and improving batch scalability of photochemical reactions. Finally, developments in red-light photoredox catalysis are leading the next-generation applications to polymer science and biochemistry-chemical biology, enabling catalytic reactions within media composites - including mammalian tissue - that are historically recalcitrant with blue-light photoredox catalysis.
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Affiliation(s)
- David C Cabanero
- Department of Chemistry, Columbia University, New York, NY, USA.
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, NY, USA.
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20
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McManus BD, Hung LC, Taylor OR, Nguyen PQ, Cedeño AL, Arriola K, Bradley RD, Saucedo PJ, Hannan RJ, Luna YA, Farias P, Bahamonde A. Mechanistic Interrogation of Photochemical Nickel-Catalyzed Tetrahydrofuran Arylation Leveraging Enantioinduction Data. J Am Chem Soc 2024; 146:32135-32146. [PMID: 39528417 DOI: 10.1021/jacs.4c13485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2024]
Abstract
This manuscript details the development of an asymmetric variant for the Ni-photoredox α-arylation of tetrahydrofuran (THF), which was originally reported in a racemic fashion by Doyle and Molander. Leveraging the enantioselectivity data that we obtained, a complex mechanistic scenario different from those originally proposed is uncovered. Specifically, an unexpected dependence of the product enantiomeric ratio was observed on both the halide identity (aryl chloride vs bromide substrates) and the Ni source. Stoichiometric experiments and time course analyses of the evolution of product enantioselectivity with time revealed a different initial behavior for reactions carried out with Ni(II) and Ni(0) precatalysts that later converge into a common mechanism. For studying the predominant pathway, this paper describes a rare example of the syntheses of chiral bisoxazoline Ni(II) aryl halide complexes, which proved essential for probing enantioselectivity via stochiometric experiments. These experiments identify the Ni(II) aryl halide complex as the primary species involved in the key THF radical trapping event. A multivariate linear regression model is presented that further validates the dominant mechanism and delineates structure-selectivity relationships between ligand properties and enantioselectivity. EPR analysis of Ni(0)/aryl halide mixtures highlights the fast access to a variety of Ni complexes in 0, +1, and +2 oxidation states that are proposed to be responsible for the initial divergence in mechanism observed when using Ni(0) precatalysts. More broadly, beyond advancing the mechanistic understanding of this THF arylation protocol, this work underscores the potential of leveraging enantioselectivity data to unravel intricate mechanistic manifolds within Ni-photoredox catalysis.
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Affiliation(s)
- Brennan D McManus
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Lang Cheng Hung
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Olivia R Taylor
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Paul Q Nguyen
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Alfredo L Cedeño
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Kyle Arriola
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Robert D Bradley
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Paul J Saucedo
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Robert J Hannan
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Yvette A Luna
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Phillip Farias
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Ana Bahamonde
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
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21
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Sarkar A, Pal AK, Kumar A, Dasgupta S, Kandoth N, Datta A, Datta A, Sen Gupta S. Ancillary Ligand-Promoted Charge Transfer in Bis-indole Pyridine Ligand-Based Nickel Complexes. Inorg Chem 2024; 63:20737-20748. [PMID: 39415415 DOI: 10.1021/acs.inorgchem.4c03419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2024]
Abstract
There is growing demand for the utilization of first-row transition metal complexes in light-driven processes instead of their conventional noble metal counterparts due to the greater sustainability of first-row transition metal complexes. However, their major drawback is the ultrafast lifetime of the electronic excited states of these first-row transition metal complexes, particularly those of d8 square-planar systems such as Ni(II) complexes, wherein low-lying metal-centered (MC) states provide the deactivation pathway. To increase the excited-state lifetime and broaden their applications, it is important to develop sterically bulky, strong field ligands with low-lying π* orbitals and a highly σ-donating nature to augment the energy of MC states. The current strategy relies on synthetically carbene-based ligands, which are substitutionally cumbersome and act as σ-donors only. In this work, we introduce a bis-indole pyridine (H2BIP) ligand framework, whose dianionic congener (BIP) demonstrates the ability to form stronger covalent bonds with a Ni(II) center compared to neutral donors like carbene and its effect on the complex to produce a less distorted excited-state structure. When conjoined with ancillary ligands such as pyridine or lutidine, the BIP ligand orchestrates the formation of low-energy 3CT states, which decay in ∼40 ps.
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Affiliation(s)
- Aniruddha Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Arun K Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Ankit Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Souradip Dasgupta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Noufal Kandoth
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Ayan Datta
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
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22
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Kumar S, Dutta S, Cavallo L, Maity B. A Comprehensive Multireference Study of Excited-State Ni-Br Bond Homolysis in (dtbbpy)Ni II(aryl)(Br). Inorg Chem 2024; 63:20361-20371. [PMID: 39417647 DOI: 10.1021/acs.inorgchem.4c02572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
The mechanism of visible light-driven Ni-C(aryl) bond homolysis in (2,2'-bipyridine)NiII(aryl)(halide) complexes, which play a crucial role in metallaphotoredox catalysis for cross-coupling reactions, has been well studied. Differently, the theoretical understanding of Ni-halide bond homolysis remains limited. In this study, we introduce a novel electronic structural framework to elucidate the mechanisms underlying photoinduced Ni-Br bond rupture in the (dtbbpy)NiII(aryl)(Br) complex. Using multireference ab initio calculations, we characterized the excited state potential energy surfaces corresponding to metal-to-ligand charge transfer (MLCT) and ligand-to-metal charge transfer (LMCT). Our calculations reveal that the Ni-Br dissociation, triggered by an external photocatalyst, begins with the promotion of Ni(II) to a 1MLCT excited state. This state undergoes intersystem crossing with repulsive triplet surfaces corresponding to the 3MLCT and Br-to-Ni 3LMCT states, resulting in Ni-Br bond breaking via the Dexter energy transfer mechanism. In the absence of a photocatalyst, the photoexcited Ni(II) favors Ni-C(aryl) homolysis, whereas the presence of a photocatalyst promotes Ni-Br dissociation. The Ni(III) species, resulting from the oxidation of Ni(II) by the photocatalyst, was found to be unproductive toward Ni-Br or Ni-C(aryl) activation.
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Affiliation(s)
- Sanchit Kumar
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Sayan Dutta
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Luigi Cavallo
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Bholanath Maity
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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23
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Garcia-Orrit S, Vega-Mayoral V, Chen Q, Serra G, Guizzardi M, Romano V, Dal Conte S, Cerullo G, Di Mario L, Kot M, Loi MA, Narita A, Müllen K, Tommasini M, Cabanillas-González J. Visualizing Thermally Activated Conical Intersections Governing Non-Radiative Triplet Decay in a Ni(II) Porphyrin-Nanographene Conjugate with Variable Temperature Transient Absorption Spectroscopy. J Phys Chem Lett 2024; 15:10366-10374. [PMID: 39374120 DOI: 10.1021/acs.jpclett.4c02712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Abstract
Metalloporphyrins based on open-shell transition metals, such as Ni(II), exhibit typically fast excited-state relaxation. In this work, we shed light into the nonradiative relaxation mechanism in a nanographene-Ni(II) porphyrin conjugate. Variable temperature transient absorption and global fit analysis are combined to produce a picture of the relaxation pathways. At room temperature, photoexcitation of the lowest π-π* transition is followed by vibrational cooling in 1.6 ps, setting a short 20 ps temporal window wherein a small fraction of relaxed singlets radiatively decay to the ground state before intersystem crossing proceeds. Following intersystem crossing, triplets relax rapidly to the ground state (S0) in a few tens of picoseconds. By performing measurements at low temperature, we provide evidence for a competition between two terminal relaxation pathways from the lowest (metal-centered) triplet to the ground state: a slow ground state relaxation process proceeding in time scales beyond 1.6 ns and a faster pathway dictated by a sloped conical intersection, which is thermally accessible at room temperature from the triplet state. The overall triplet decay at a given temperature is dictated by the interplay of these two contributions. This observation bears significance in understanding the underlying fast relaxation processes in Ni-based molecules and related transition metal complexes, opening avenues for potential applications for energy harvesting and optoelectronics.
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Affiliation(s)
- Saül Garcia-Orrit
- Madrid Institute for Advanced Studies, IMDEA Nanociencia, c/Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Víctor Vega-Mayoral
- Madrid Institute for Advanced Studies, IMDEA Nanociencia, c/Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Qiang Chen
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Gianluca Serra
- Dipartimento di Chimica, Materiali ed Ingegneria Chimica "G.Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)
| | - Michele Guizzardi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy
| | - Valentino Romano
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy
| | - Stefano Dal Conte
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy
| | - Lorenzo Di Mario
- Photophysics and OptoElectronics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 3, 9747 AG, Groningen, The Netherlands
| | - Mordechai Kot
- Photophysics and OptoElectronics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 3, 9747 AG, Groningen, The Netherlands
| | - Maria Antonietta Loi
- Photophysics and OptoElectronics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 3, 9747 AG, Groningen, The Netherlands
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Institute for Physical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Matteo Tommasini
- Dipartimento di Chimica, Materiali ed Ingegneria Chimica "G.Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)
| | - Juan Cabanillas-González
- Madrid Institute for Advanced Studies, IMDEA Nanociencia, c/Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
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24
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Oliva M, Pillitteri S, Schörgenhumer J, Saito R, Van der Eycken EV, Sharma UK. Bromine radical release from a nickel-complex facilitates the activation of alkyl boronic acids: a boron selective Suzuki-Miyaura cross coupling. Chem Sci 2024:d4sc04196h. [PMID: 39371457 PMCID: PMC11450759 DOI: 10.1039/d4sc04196h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Accepted: 09/19/2024] [Indexed: 10/08/2024] Open
Abstract
In this study, without utilizing any exogenous activator or strong oxidants, we successfully employed inactivated and easily accessible alkyl boronic acids (BAs) as coupling partners in a photocatalyzed Suzuki-Miyaura reaction under batch and continuous-flow conditions. Detailed mechanistic studies suggest a unique BA activation pathway, via a plausible radical transfer event between a bromine radical (formed in situ via a photo-induced homolysis of the Ni-Br bond) and the empty p-orbital on the boron atom. Subsequently, the necessity to tune the BA oxidation potential by means of hydrogen-bonding interaction with solvents or Lewis acid-base type interactions is replaced by a novel halogen radical transfer (XRT) mechanism. The mechanistic hypothesis has been supported by both control experiments and DFT calculations.
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Affiliation(s)
- Monica Oliva
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
| | - Serena Pillitteri
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
| | - Johannes Schörgenhumer
- Department of Chemistry, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Riku Saito
- Department of Chemistry and Centre for Sustainable Chemistry, Ghent University Krijgslaan 281 (S3) 9000 Ghent Belgium
| | - Erik V Van der Eycken
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
- Peoples' Friendship University of Russia (RUDN University) Miklukho-Maklaya Street 6 117198 Moscow Russia
| | - Upendra K Sharma
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard St. Louis MO 63121 USA
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25
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Barth AT, Pyrch AJ, McCormick CT, Danilov EO, Castellano FN. Excited State Bond Homolysis of Vanadium(V) Photocatalysts for Alkoxy Radical Generation. J Phys Chem A 2024; 128:7609-7619. [PMID: 39213596 DOI: 10.1021/acs.jpca.4c04250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Advancements in photocatalysis have transformed synthetic organic chemistry, using light as a powerful tool to drive selective chemical transformations. Recent approaches have focused on metal-halide ligand-to-metal charge transfer (LMCT) photoactivated bond homolysis reactions leveraged by earth-abundant elements to generate valuable synthons for radical-mediated cross-coupling reactions. Of recent utility, oxovanadium(V) LMCT photocatalysts exhibit selective alkoxy radical generation from aliphatic alcohols upon blue light (UVA) irradiation under mild conditions. The selective photochemical liberation of alkoxy radicals is valuable for applying late-stage fragmentation approaches in organic synthesis and depolymerization strategies for nonbiodegradable polymers. Steady-state and time-resolved spectroscopy were used to assign the electronic structure of three well-defined V(V) photocatalysts in their ground and excited states. We assign the excited state for this transformation at earth-abundant vanadium(V), interrogating the electronic structure using static UV-visible absorption, ultrafast transient absorption, and electron paramagnetic resonance spectroscopy coupled to computational approaches. These findings afford assignments of the short-lived excited state intermediates that dictate selective homolytic bond cleavage in metal alkoxides, illustrating the valuable insight gleaned from fundamental investigations of the molecular photochemistry responsible for light-escalated chemical transformations.
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Affiliation(s)
- Alexandra T Barth
- North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Austin J Pyrch
- North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Conor T McCormick
- North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Evgeny O Danilov
- North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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26
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Jung H, Choi J, Kim D, Lee JH, Ihee H, Kim D, Chang S. Photoinduced Group Transposition via Iridium-Nitrenoid Leading to Amidative Inner-Sphere Aryl Migration. Angew Chem Int Ed Engl 2024; 63:e202408123. [PMID: 38871650 DOI: 10.1002/anie.202408123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 06/15/2024]
Abstract
We herein report a fundamental mechanistic investigation into photochemical metal-nitrenoid generation and inner-sphere transposition reactivity using organometallic photoprecursors. By designing Cp*Ir(hydroxamate)(Ar) complexes, we induced photo-initiated ligand activation, allowing us to explore the amidative σ(Ir-aryl) migration reactivity. A combination of experimental mechanistic studies, femtosecond transient absorption spectroscopy, and density functional theory (DFT) calculations revealed that the metal-to-ligand charge transfer enables the σ(N-O) cleavage, followed by Ir-acylnitrenoid generation. The final inner-sphere σ(Ir-aryl) group migration results in a net amidative group transposition.
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Affiliation(s)
- Hoimin Jung
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jungkweon Choi
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Daniel Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jeong Hoon Lee
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hyotcherl Ihee
- Center for Advanced Reaction Dynamics, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Sukbok Chang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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27
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Dinh LP, Starbuck HF, Hamby TB, LaLama MJ, He CQ, Kalyani D, Sevov CS. Persistent organonickel complexes as general platforms for Csp 2-Csp 3 coupling reactions. Nat Chem 2024; 16:1515-1522. [PMID: 38684816 PMCID: PMC11374490 DOI: 10.1038/s41557-024-01528-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 04/03/2024] [Indexed: 05/02/2024]
Abstract
The importance of constructing Csp2-Csp3 bonds has motivated the development of electrochemical, photochemical and thermal activation methods to reductively couple abundant aryl and alkyl electrophiles. However, these methodologies are limited to couplings of very specific substrate classes and require specialized sets of catalysts and reaction set-ups. Here we show a consolidation of these myriad strategies into a single set of conditions that enable reliable alkyl-aryl couplings, including those that were previously unknown. These reactions rely on the discovery of unusually persistent organonickel complexes that serve as stoichiometric platforms for C(sp2)-C(sp3) coupling. Aryl, heteroaryl or vinyl complexes of Ni can be inexpensively prepared on a multigram scale by mild electroreduction from the corresponding C(sp2) electrophile. Organonickel complexes can be isolated and stored or telescoped directly to reliably diversify drug-like molecules. Finally, the procedure was miniaturized to micromole scales by integrating soluble battery chemistries as redox initiators, enabling a high-throughput exploration of substrate diversity.
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Affiliation(s)
- Long P Dinh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Hunter F Starbuck
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Taylor B Hamby
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Matthew J LaLama
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Cyndi Q He
- Modelling & Informatics, Merck & Co., Inc., Rahway, NJ, USA
| | | | - Christo S Sevov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.
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28
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Beil SB, Bonnet S, Casadevall C, Detz RJ, Eisenreich F, Glover SD, Kerzig C, Næsborg L, Pullen S, Storch G, Wei N, Zeymer C. Challenges and Future Perspectives in Photocatalysis: Conclusions from an Interdisciplinary Workshop. JACS AU 2024; 4:2746-2766. [PMID: 39211583 PMCID: PMC11350580 DOI: 10.1021/jacsau.4c00527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 07/25/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024]
Abstract
Photocatalysis is a versatile and rapidly developing field with applications spanning artificial photosynthesis, photo-biocatalysis, photoredox catalysis in solution or supramolecular structures, utilization of abundant metals and organocatalysts, sustainable synthesis, and plastic degradation. In this Perspective, we summarize conclusions from an interdisciplinary workshop of young principal investigators held at the Lorentz Center in Leiden in March 2023. We explore how diverse fields within photocatalysis can benefit from one another. We delve into the intricate interplay between these subdisciplines, by highlighting the unique challenges and opportunities presented by each field and how a multidisciplinary approach can drive innovation and lead to sustainable solutions for the future. Advanced collaboration and knowledge exchange across these domains can further enhance the potential of photocatalysis. Artificial photosynthesis has become a promising technology for solar fuel generation, for instance, via water splitting or CO2 reduction, while photocatalysis has revolutionized the way we think about assembling molecular building blocks. Merging such powerful disciplines may give rise to efficient and sustainable protocols across different technologies. While photocatalysis has matured and can be applied in industrial processes, a deeper understanding of complex mechanisms is of great importance to improve reaction quantum yields and to sustain continuous development. Photocatalysis is in the perfect position to play an important role in the synthesis, deconstruction, and reuse of molecules and materials impacting a sustainable future. To exploit the full potential of photocatalysis, a fundamental understanding of underlying processes within different subfields is necessary to close the cycle of use and reuse most efficiently. Following the initial interactions at the Lorentz Center Workshop in 2023, we aim to stimulate discussions and interdisciplinary approaches to tackle these challenges in diverse future teams.
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Affiliation(s)
- Sebastian B. Beil
- Stratingh
Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
- Max Planck
Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mulheim an der Ruhr, Germany
| | - Sylvestre Bonnet
- Leiden Institute
of Chemistry, Leiden University, Gorlaeus
Laboratories, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Carla Casadevall
- Department
of Physical and Inorganic Chemistry, University
Rovira i Virgili (URV), C/Marcel.lí Domingo, 1, 43007 Tarragona, Spain
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute
of Science and Technology, Avinguda dels Països Catalans, 16, 43007 Tarragona, Spain
| | - Remko J. Detz
- Energy Transition
Studies (ETS), Netherlands Organization
for Applied Scientific Research (TNO), Radarweg 60, 1043
NT Amsterdam, The
Netherlands
| | - Fabian Eisenreich
- Department
of Chemical Engineering and Chemistry & Institute for Complex
Molecular Systems, Eindhoven University
of Technology, 5600 MB Eindhoven, The Netherlands
| | - Starla D. Glover
- Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Christoph Kerzig
- Department
of Chemistry, Johannes Gutenberg University
Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Line Næsborg
- Department
of Organic Chemistry, University of Münster, Correnstr. 40, 48149 Münster, Germany
| | - Sonja Pullen
- Homogeneous
and Supramolecular Catalysis, Van ’t Hoff Institute for Molecular
Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Golo Storch
- Technical
University of Munich (TUM), Lichtenbergstr. 4, 85747 Garching, Germany
| | - Ning Wei
- Stratingh
Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
- Max Planck
Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mulheim an der Ruhr, Germany
| | - Cathleen Zeymer
- Center for
Functional Protein Assemblies & Department of Bioscience, TUM
School of Natural Sciences, Technical University
of Munich, 85748 Garching, Germany
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29
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Treacy SM, Rovis T. Photoinduced Ligand-to-Metal Charge Transfer in Base-Metal Catalysis. SYNTHESIS-STUTTGART 2024; 56:1967-1978. [PMID: 38962497 PMCID: PMC11218547 DOI: 10.1055/s-0042-1751518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The absorption of light by photosensitizers has been shown to offer novel reactive pathways through electronic excited state intermediates, complementing ground state mechanisms. Such strategies have been applied in both photocatalysis and photoredox catalysis, driven by generating reactive intermediates from their long-lived excited states. One developing area is photoinduced ligand-to-metal charge transfer (LMCT) catalysis, in which coordination of a ligand to a metal center and subsequent excitation with light results in the formation of a reactive radical and a reduced metal center. This mini review concerns the foundations and recent developments in ligand-to-metal charge transfer in transition metal catalysis focusing on the organic transformations made possible through this mechanism.
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Affiliation(s)
- S M Treacy
- Columbia University, Department of Chemistry, 3000 Broadway, Havemeyer Hall, New York, NY 10027, USA
| | - T Rovis
- Columbia University, Department of Chemistry, 3000 Broadway, Havemeyer Hall, New York, NY 10027, USA
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30
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Goodwin MJ, Dickenson JC, Ripak A, Deetz AM, McCarthy JS, Meyer GJ, Troian-Gautier L. Factors that Impact Photochemical Cage Escape Yields. Chem Rev 2024; 124:7379-7464. [PMID: 38743869 DOI: 10.1021/acs.chemrev.3c00930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The utilization of visible light to mediate chemical reactions in fluid solutions has applications that range from solar fuel production to medicine and organic synthesis. These reactions are typically initiated by electron transfer between a photoexcited dye molecule (a photosensitizer) and a redox-active quencher to yield radical pairs that are intimately associated within a solvent cage. Many of these radicals undergo rapid thermodynamically favored "geminate" recombination and do not diffuse out of the solvent cage that surrounds them. Those that do escape the cage are useful reagents that may undergo subsequent reactions important to the above-mentioned applications. The cage escape process and the factors that determine the yields remain poorly understood despite decades of research motivated by their practical and fundamental importance. Herein, state-of-the-art research on light-induced electron transfer and cage escape that has appeared since the seminal 1972 review by J. P. Lorand entitled "The Cage Effect" is reviewed. This review also provides some background for those new to the field and discusses the cage escape process of both homolytic bond photodissociation and bimolecular light induced electron transfer reactions. The review concludes with some key goals and directions for future research that promise to elevate this very vibrant field to even greater heights.
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Affiliation(s)
- Matthew J Goodwin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - John C Dickenson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Alexia Ripak
- Université catholique de Louvain (UCLouvain), Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, bte L4.01.02, 1348 Louvain-la-Neuve, Belgium
| | - Alexander M Deetz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jackson S McCarthy
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ludovic Troian-Gautier
- Université catholique de Louvain (UCLouvain), Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, bte L4.01.02, 1348 Louvain-la-Neuve, Belgium
- Wel Research Institute, Avenue Pasteur 6, 1300 Wavre, Belgium
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31
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Iwai T, Abe S, Takizawa SY, Masai H, Terao J. Insulated π-conjugated 2,2'-bipyridine transition-metal complexes: enhanced photoproperties in luminescence and catalysis. Chem Sci 2024; 15:8873-8879. [PMID: 38873064 PMCID: PMC11168077 DOI: 10.1039/d4sc01046a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 05/03/2024] [Indexed: 06/15/2024] Open
Abstract
2,2'-Bipyridine has been identified as a privileged ligand scaffold for photofunctional transition metal complexes. We herein report on the synthesis and photoproperties of an insulated π-conjugated 2,2'-bipyridine with a linked rotaxane structure consisting of permethylated α-cyclodextrin (PM α-CD) and oligo(p-phenylene ethynylene). The insulated π-conjugated 2,2'-bipyridine exhibited enhanced ligand performance in the solid-state emitting biscyclometalated Ir complexes and visible-light-driven Ni catalysts owing to π-extension and remote steric effects based on the linked rotaxane structure.
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Affiliation(s)
- Tomohiro Iwai
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1, Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Shinsuke Abe
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1, Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Shin-Ya Takizawa
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1, Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Hiroshi Masai
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1, Komaba, Meguro-ku Tokyo 153-8902 Japan
- PRESTO, Japan Science and Technology Agency 4-1-8 Honcho 332-0012 Kawaguchi Saitama Japan
| | - Jun Terao
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1, Komaba, Meguro-ku Tokyo 153-8902 Japan
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32
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Cagan D, Bím D, Kazmierczak NP, Hadt RG. Mechanisms of Photoredox Catalysis Featuring Nickel-Bipyridine Complexes. ACS Catal 2024; 14:9055-9076. [PMID: 38868098 PMCID: PMC11165457 DOI: 10.1021/acscatal.4c02036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/07/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024]
Abstract
Metallaphotoredox catalysis can unlock useful pathways for transforming organic reactants into desirable products, largely due to the conversion of photon energy into chemical potential to drive redox and bond transformation processes. Despite the importance of these processes for cross-coupling reactions and other transformations, their mechanistic details are only superficially understood. In this review, we have provided a detailed summary of various photoredox mechanisms that have been proposed to date for Ni-bipyridine (bpy) complexes, focusing separately on photosensitized and direct excitation reaction processes. By highlighting multiple bond transformation pathways and key findings, we depict how photoredox reaction mechanisms, which ultimately define substrate scope, are themselves defined by the ground- and excited-state geometric and electronic structures of key Ni-based intermediates. We further identify knowledge gaps to motivate future mechanistic studies and the development of synergistic research approaches spanning the physical, organic, and inorganic chemistry communities.
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Affiliation(s)
- David
A. Cagan
- Division
of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory
of Chemical Physics, California Institute
of Technology, Pasadena, California 91125, United States
| | - Daniel Bím
- Institute
of Organic Chemistry and Biochemistry, The
Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Nathanael P. Kazmierczak
- Division
of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory
of Chemical Physics, California Institute
of Technology, Pasadena, California 91125, United States
| | - Ryan G. Hadt
- Division
of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory
of Chemical Physics, California Institute
of Technology, Pasadena, California 91125, United States
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33
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Cusumano AQ, Chaffin BC, Doyle AG. Mechanism of Ni-Catalyzed Photochemical Halogen Atom-Mediated C(sp 3)-H Arylation. J Am Chem Soc 2024; 146:15331-15344. [PMID: 38778454 PMCID: PMC11246173 DOI: 10.1021/jacs.4c03099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Within the context of Ni photoredox catalysis, halogen atom photoelimination from Ni has emerged as a fruitful strategy for enabling hydrogen atom transfer (HAT)-mediated C(sp3)-H functionalization. Despite the numerous synthetic transformations invoking this paradigm, a unified mechanistic hypothesis that is consistent with experimental findings on the catalytic systems and accounts for halogen radical formation and facile C(sp2)-C(sp3) bond formation remains elusive. We employ kinetic analysis, organometallic synthesis, and computational investigations to decipher the mechanism of a prototypical Ni-catalyzed photochemical C(sp3)-H arylation reaction. Our findings revise the previous mechanistic proposals, first by examining the relevance of SET and EnT processes from Ni intermediates relevant to the HAT-based arylation reaction. Our investigation highlights the ability for blue light to promote efficient Ni-C(sp2) bond homolysis from cationic NiIII and C(sp2)-C(sp3) reductive elimination from bipyridine NiII complexes. However interesting, the rates and selectivities of these processes do not account for the productive catalytic pathway. Instead, our studies support a mechanism that involves halogen atom evolution from in situ generated NiII dihalide intermediates, radical capture by a NiII(aryl)(halide) resting state, and key C-C bond formation from NiIII. Oxidative addition to NiI, as opposed to Ni0, and rapid NiIII/NiI comproportionation play key roles in this process. The findings presented herein offer fundamental insight into the reactivity of Ni in the broader context of catalysis.
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Affiliation(s)
- Alexander Q Cusumano
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Braden C Chaffin
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Abigail G Doyle
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
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34
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Sutcliffe E, Cagan DA, Hadt RG. Ultrafast Photophysics of Ni(I)-Bipyridine Halide Complexes: Spanning the Marcus Normal and Inverted Regimes. J Am Chem Soc 2024; 146:15506-15514. [PMID: 38776490 PMCID: PMC11157544 DOI: 10.1021/jacs.4c04091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Owing to their light-harvesting properties, nickel-bipyridine (bpy) complexes have found wide use in metallaphotoredox cross-coupling reactions. Key to these transformations are Ni(I)-bpy halide intermediates that absorb a significant fraction of light at relevant cross-coupling reaction irradiation wavelengths. Herein, we report ultrafast transient absorption (TA) spectroscopy on a library of eight Ni(I)-bpy halide complexes, the first such characterization of any Ni(I) species. The TA data reveal the formation and decay of Ni(I)-to-bpy metal-to-ligand charge transfer (MLCT) excited states (10-30 ps) whose relaxation dynamics are well described by vibronic Marcus theory, spanning the normal and inverted regions as a result of simple changes to the bpy substituents. While these lifetimes are relatively long for MLCT excited states in first-row transition metal complexes, their duration precludes excited-state bimolecular reactivity in photoredox reactions. We also present a one-step method to generate an isolable, solid-state Ni(I)-bpy halide species, which decouples light-initiated reactivity from dark, thermal cycles in catalysis.
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Affiliation(s)
| | | | - Ryan G. Hadt
- Division of Chemistry and
Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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35
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Trippmacher S, Demeshko S, Prescimone A, Meyer F, Wenger OS, Wang C. Ferromagnetically Coupled Chromium(III) Dimer Shows Luminescence and Sensitizes Photon Upconversion. Chemistry 2024; 30:e202400856. [PMID: 38523568 DOI: 10.1002/chem.202400856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/23/2024] [Accepted: 03/25/2024] [Indexed: 03/26/2024]
Abstract
There has been much progress on mononuclear chromium(III) complexes featuring luminescence and photoredox activity, but dinuclear chromium(III) complexes have remained underexplored in these contexts until now. We identified a tridentate chelate ligand able to accommodate both meridional and facial coordination of chromium(III), to either access a mono- or a dinuclear chromium(III) complex depending on reaction conditions. This chelate ligand causes tetragonally distorted primary coordination spheres around chromium(III) in both complexes, entailing comparatively short excited-state lifetimes in the range of 400 to 800 ns in solution at room temperature and making photoluminescence essentially oxygen insensitive. The two chromium(III) ions in the dimer experience ferromagnetic exchange interactions that result in a high spin (S=3) ground state with a coupling constant of +9.3 cm-1. Photoinduced energy transfer from the luminescent ferromagnetically coupled dimer to an anthracene derivative results in sensitized triplet-triplet annihilation upconversion. Based on these proof-of-principle studies, dinuclear chromium(III) complexes seem attractive for the development of fundamentally new types of photophysics and photochemistry enabled by magnetic exchange interactions.
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Affiliation(s)
- Simon Trippmacher
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Alessandro Prescimone
- Department of Chemistry, BPR 1096, University of Basel, Mattenstrasse 24a, 4058, Basel, Switzerland
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Cui Wang
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Department of Biology and Chemistry, Osnabrück University, Barbarastraße 7, 49076, Osnabrück, Germany
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36
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Wallick R, Chakrabarti S, Burke JH, Gnewkow R, Chae JB, Rossi TC, Mantouvalou I, Kanngießer B, Fondell M, Eckert S, Dykstra C, Smith LE, Vura-Weis J, Mirica LM, van der Veen RM. Excited-State Identification of a Nickel-Bipyridine Photocatalyst by Time-Resolved X-ray Absorption Spectroscopy. J Phys Chem Lett 2024; 15:4976-4982. [PMID: 38691639 PMCID: PMC11089568 DOI: 10.1021/acs.jpclett.4c00226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/18/2024] [Accepted: 04/16/2024] [Indexed: 05/03/2024]
Abstract
Photoassisted catalysis using Ni complexes is an emerging field for cross-coupling reactions in organic synthesis. However, the mechanism by which light enables and enhances the reactivity of these complexes often remains elusive. Although optical techniques have been widely used to study the ground and excited states of photocatalysts, they lack the specificity to interrogate the electronic and structural changes at specific atoms. Herein, we report metal-specific studies using transient Ni L- and K-edge X-ray absorption spectroscopy of a prototypical Ni photocatalyst, (dtbbpy)Ni(o-tol)Cl (dtb = 4,4'-di-tert-butyl, bpy = bipyridine, o-tol = ortho-tolyl), in solution. We unambiguously confirm via direct experimental evidence that the long-lived (∼5 ns) excited state is a tetrahedral metal-centered triplet state. These results demonstrate the power of ultrafast X-ray spectroscopies to unambiguously elucidate the nature of excited states in important transition-metal-based photocatalytic systems.
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Affiliation(s)
- Rachel
F. Wallick
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Sagnik Chakrabarti
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - John H. Burke
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Richard Gnewkow
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
- Institute
of Optics and Atomic Physics, Technische
Universität Berlin, Berlin 10623, Germany
| | - Ju Byeong Chae
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Thomas C. Rossi
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
| | - Ioanna Mantouvalou
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
- Institute
of Optics and Atomic Physics, Technische
Universität Berlin, Berlin 10623, Germany
| | - Birgit Kanngießer
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
- Institute
of Optics and Atomic Physics, Technische
Universität Berlin, Berlin 10623, Germany
| | - Mattis Fondell
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
| | - Sebastian Eckert
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
| | - Conner Dykstra
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Laura E. Smith
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Josh Vura-Weis
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Liviu M. Mirica
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
| | - Renske M. van der Veen
- Department
of Chemistry, University of Illinois at
Urbana—Champaign, Urbana, Illinois 61801, United States
- Department
of Atomic-Scale Dynamics in Light-Energy Conversion, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 14109, Germany
- Institute
of Optics and Atomic Physics, Technische
Universität Berlin, Berlin 10623, Germany
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Wellauer J, Ziereisen F, Sinha N, Prescimone A, Velić A, Meyer F, Wenger OS. Iron(III) Carbene Complexes with Tunable Excited State Energies for Photoredox and Upconversion. J Am Chem Soc 2024; 146. [PMID: 38598280 PMCID: PMC11046485 DOI: 10.1021/jacs.4c00605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/11/2024]
Abstract
Substituting precious elements in luminophores and photocatalysts by abundant first-row transition metals remains a significant challenge, and iron continues to be particularly attractive owing to its high natural abundance and low cost. Most iron complexes known to date face severe limitations due to undesirably efficient deactivation of luminescent and photoredox-active excited states. Two new iron(III) complexes with structurally simple chelate ligands enable straightforward tuning of ground and excited state properties, contrasting recent examples, in which chemical modification had a minor impact. Crude samples feature two luminescence bands strongly reminiscent of a recent iron(III) complex, in which this observation was attributed to dual luminescence, but in our case, there is clear-cut evidence that the higher-energy luminescence stems from an impurity and only the red photoluminescence from a doublet ligand-to-metal charge transfer (2LMCT) excited state is genuine. Photoinduced oxidative and reductive electron transfer reactions with methyl viologen and 10-methylphenothiazine occur with nearly diffusion-limited kinetics. Photocatalytic reactions not previously reported for this compound class, in particular the C-H arylation of diazonium salts and the aerobic hydroxylation of boronic acids, were achieved with low-energy red light excitation. Doublet-triplet energy transfer (DTET) from the luminescent 2LMCT state to an anthracene annihilator permits the proof of principle for triplet-triplet annihilation upconversion based on a molecular iron photosensitizer. These findings are relevant for the development of iron complexes featuring photophysical and photochemical properties competitive with noble-metal-based compounds.
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Affiliation(s)
- Joël Wellauer
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Fabienne Ziereisen
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Narayan Sinha
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Ajdin Velić
- University
of Göttingen, Institute of Inorganic Chemistry, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Franc Meyer
- University
of Göttingen, Institute of Inorganic Chemistry, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Oliver S. Wenger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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38
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Mills LR, Simmons EM, Lee H, Nester E, Kim J, Wisniewski SR, Pecoraro MV, Chirik PJ. (Phenoxyimine)nickel-Catalyzed C(sp 2)-C(sp 3) Suzuki-Miyaura Cross-Coupling: Evidence for a Recovering Radical Chain Mechanism. J Am Chem Soc 2024; 146:10124-10141. [PMID: 38557045 DOI: 10.1021/jacs.4c01474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Phenoxyimine (FI)-nickel(II)(2-tolyl)(DMAP) compounds were synthesized and evaluated as precatalysts for the C(sp2)-C(sp3) Suzuki-Miyaura cross coupling of (hetero)arylboronic acids with alkyl bromides. With 5 mol % of the optimal (MeOMeFI)Ni(Aryl)(DMAP) precatalyst, the scope of the cross-coupling reaction was established and included a variety of (hetero)arylboronic acids and alkyl bromides (>50 examples, 33-97% yield). A β-hydride elimination-reductive elimination sequence from reaction with potassium isopropoxide base, yielding a potassium (FI)nickel(0)ate, was identified as a catalyst activation pathway that is responsible for halogen atom abstraction from the alkyl bromide. A combination of NMR and EPR spectroscopies identified (FI)nickel(II)-aryl complexes as the resting state during catalysis with no evidence for long-lived organic radical or odd-electron nickel intermediates. These data establish that the radical chain is short-lived and undergoes facile termination and also support a "recovering radical chain" process whereby the (FI)nickel(II)-aryl compound continually (re)initiates the radical chain. Kinetic studies established that the rate of C(sp2)-C(sp3) product formation was proportional to the concentration of the (FI)nickel(II)-aryl resting state that captures the alkyl radical for chain propagation. The proposed mechanism involves two key and concurrently operating catalytic cycles; the first involving a nickel(I/II/III) radical propagation cycle consisting of radical capture at (FI)nickel(II)-aryl, C(sp2)-C(sp3) reductive elimination, bromine atom abstraction from C(sp3)-Br, and transmetalation; and the second involving an off-cycle catalyst recovery process by slow (FI)nickel(II)-aryl → (FI)nickel(0)ate conversion for nickel(I) regeneration.
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Affiliation(s)
- L Reginald Mills
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Eric M Simmons
- Chemical Process Development, Bristol Myers Squibb Company, New Brunswick, New Jersey 08903, United States
| | - Heejun Lee
- Chemical Process Development, Bristol Myers Squibb Company, New Brunswick, New Jersey 08903, United States
| | - Eva Nester
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Junho Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Steven R Wisniewski
- Chemical Process Development, Bristol Myers Squibb Company, New Brunswick, New Jersey 08903, United States
| | - Matthew V Pecoraro
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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39
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Bím D, Luedecke KM, Cagan DA, Hadt RG. Light Activation and Photophysics of a Structurally Constrained Nickel(II)-Bipyridine Aryl Halide Complex. Inorg Chem 2024; 63:4120-4131. [PMID: 38376134 PMCID: PMC11000520 DOI: 10.1021/acs.inorgchem.3c03822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Transition-metal photoredox catalysis has transformed organic synthesis by harnessing light to construct complex molecules. Nickel(II)-bipyridine (bpy) aryl halide complexes are a significant class of cross-coupling catalysts that can be activated via direct light excitation. This study investigates the effects of molecular structure on the photophysics of these catalysts by considering an underexplored, structurally constrained Ni(II)-bpy aryl halide complex in which the aryl and bpy ligands are covalently tethered alongside traditional unconstrained complexes. Intriguingly, the tethered complex is photochemically stable but features a reversible Ni(II)-C(aryl) ⇄ [Ni(I)···C(aryl)•] equilibrium upon direct photoexcitation. When an electrophile is introduced during photoirradiation, we demonstrate a preference for photodissociation over recombination, rendering the parent Ni(II) complex a stable source of a reactive Ni(I) intermediate. Here, we characterize the reversible photochemical behavior of the tethered complex by kinetic analyses, quantum chemical calculations, and ultrafast transient absorption spectroscopy. Comparison to the previously characterized Ni(II)-bpy aryl halide complex indicates that the structural constraints considered here dramatically influence the excited state relaxation pathway and provide insight into the characteristics of excited-state Ni(II)-C bond homolysis and aryl radical reassociation dynamics. This study enriches the understanding of molecular structure effects in photoredox catalysis and offers new possibilities for designing customized photoactive catalysts for precise organic synthesis.
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Affiliation(s)
- Daniel Bím
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Kaitlin M Luedecke
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - David A Cagan
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Ryan G Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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40
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Karpova L, Daniel M, Kancherla R, Muralirajan K, Maity B, Rueping M. Excited-State Nickel-Catalyzed Amination of Aryl Bromides: Synthesis of Diphenylamines and Primary Anilines. Org Lett 2024; 26:1657-1661. [PMID: 38381879 DOI: 10.1021/acs.orglett.4c00147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Excited-state nickel-catalyzed C-N cross-coupling of aryl bromides with sodium azide enables the synthesis of diarylamines and primary anilines under mild reaction conditions. The oxidative addition of electron-rich aryl bromides with low-valent Ni under the photochemical conditions is endothermic. Herein, we demonstrate a light-mediated nickel-catalyzed reaction of electronically rich aryl bromides that yields diarylamines, while the reaction with electron-deficient aryl bromides gives access to anilines at room temperature.
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Affiliation(s)
- Lidia Karpova
- Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Matěj Daniel
- Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Rajesh Kancherla
- Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Krishnamoorthy Muralirajan
- Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Bholanath Maity
- Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Magnus Rueping
- Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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41
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Gao J, He XC, Liu YL, Yao PP, Guan JP, Chen K, Xiang HY, Yang H. Photoredox/Nickel Dual Catalysis-Enabled Aryl Formylation with 2,2-Dimethoxy- N, N-dimethylethan-1-amine as CO Source. Org Lett 2024; 26:1478-1482. [PMID: 38334422 DOI: 10.1021/acs.orglett.4c00139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Herein, a dual photoredox/nickel catalyzed formylation of aryl bromide with commercially available 2,2-dimethoxy-N,N-dimethylethan-1-amine as an effective CO source has been successfully achieved, delivering a series of aromatic aldehydes in moderate to good yields. Compared with the traditional reductive carbonylation process, this newly designed synthetic protocol provides a straightforward toolbox to access aromatic aldehydes, obviating the use of carbon monoxide and stoichiometric reductants. Finally, the utility of this direct formylation reaction was demonstrated in the pharmaceutical analogue synthesis.
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Affiliation(s)
- Jie Gao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Xian-Chen He
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Yan-Ling Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Pin-Pin Yao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Jian-Ping Guan
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Kai Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Hao-Yue Xiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, Henan P. R. China
| | - Hua Yang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
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42
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Yan Y, Wang P, Wang Y, Dong J, Li G, Wang C, Xue D. Light-Triggered, Ni-Catalyzed Cyanation of Aryl Triflates with 1,4-Dicyanobenzene as the CN Source. Org Lett 2024; 26:1370-1375. [PMID: 38358108 DOI: 10.1021/acs.orglett.3c04294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
A light-triggered, Ni-catalyzed cyanation of aryl triflates was herein reported, which provides a benign photochemical synthesis of aryl nitriles using 1,4-dicyanobenzene as the CN source instead of HCN or a metallic CN source. This mild method uses a readily available bisphosphine ligand and a soluble organosilicon reagent as the reductant and is carried out under purple light without an external photocatalyst. This cyanation was effective for aryl triflates derived from phenols and bisphenols as well as lignin-derived phenolic compounds, demonstrating its potential utility for the synthesis of aryl nitriles from biomass.
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Affiliation(s)
- Yonggang Yan
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Pengpeng Wang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Yuying Wang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Jianyang Dong
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Gang Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Chao Wang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Dong Xue
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
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43
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Dutta S, Erchinger JE, Strieth-Kalthoff F, Kleinmans R, Glorius F. Energy transfer photocatalysis: exciting modes of reactivity. Chem Soc Rev 2024; 53:1068-1089. [PMID: 38168974 DOI: 10.1039/d3cs00190c] [Citation(s) in RCA: 89] [Impact Index Per Article: 89.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Excited (triplet) states offer a myriad of attractive synthetic pathways, including cycloadditions, selective homolytic bond cleavages and strain-release chemistry, isomerizations, deracemizations, or the fusion with metal catalysis. Recent years have seen enormous advantages in enabling these reactivity modes through visible-light-mediated triplet-triplet energy transfer catalysis (TTEnT). This tutorial review provides an overview of this emerging strategy for synthesizing sought-after organic motifs in a mild, selective, and sustainable manner. Building on the photophysical foundations of energy transfer, this review also discusses catalyst design, as well as the challenges and opportunities of energy transfer catalysis.
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Affiliation(s)
- Subhabrata Dutta
- University of Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149 Münster, Germany.
| | - Johannes E Erchinger
- University of Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149 Münster, Germany.
| | - Felix Strieth-Kalthoff
- University of Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149 Münster, Germany.
| | - Roman Kleinmans
- University of Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149 Münster, Germany.
| | - Frank Glorius
- University of Münster, Organisch-Chemisches Institut, Corrensstraße 36, 48149 Münster, Germany.
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44
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Song G, Song J, Li Q, Nong DZ, Dong J, Li G, Fan J, Wang C, Xiao J, Xue D. Werner Salt as Nickel and Ammonia Source for Photochemical Synthesis of Primary Aryl Amines. Angew Chem Int Ed Engl 2024; 63:e202314355. [PMID: 37914669 DOI: 10.1002/anie.202314355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/03/2023]
Abstract
Cheap, stable and easy-to-handle Werner ammine salts have been known for more than a century; but they have been rarely used in organic synthesis. Herein, we report that the Werner hexammine complex [Ni(NH3 )6 ]Cl2 can be used as both a nitrogen and a catalytic nickel source that allow for the efficient amination of aryl chlorides in the presence of a catalytic amount of bipyridine ligand under the irradiation of 390-395 nm light without the need of any additional catalysts. More than 80 aryl chlorides, including more than 20 drug molecules, were aminated, demonstrating the practicality and generality of this method in synthetic chemistry. A slow NH3 release mechanism is in operation, obviating the problem of catalyst poisoning. Still interestingly, we show that the Werner salt can be easily recovered and reused, solving the problem of difficult recovery of transition metal nickel catalysts. The protocol thus provides an efficient new strategy for the synthesis of primary aryl amines.
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Affiliation(s)
- Geyang Song
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Jiameng Song
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Qi Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Ding-Zhan Nong
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Jianyang Dong
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Gang Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Juan Fan
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Chao Wang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
| | - Jianliang Xiao
- Department of Chemistry, University of Liverpool, L69 7ZD, Liverpool, UK
| | - Dong Xue
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710062, Xi'an, China
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45
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Waddell PM, Tian L, Scavuzzo AR, Venigalla L, Scholes GD, Carrow BP. Visible light-induced palladium-carbon bond weakening in catalytically relevant T-shaped complexes. Chem Sci 2023; 14:14217-14228. [PMID: 38098701 PMCID: PMC10717500 DOI: 10.1039/d3sc02588h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 10/26/2023] [Indexed: 12/17/2023] Open
Abstract
Triggering one-electron redox processes during palladium catalysis holds the potential to unlock new reaction mechanisms and synthetic methods not previously accessible in the typical two-electron reaction manifolds that dominate palladium catalysis. We report that T-shaped organopalladium(ii) complexes coordinated by a bulky monophosphine, a class of organometallic intermediate featured in a range of contemporary catalytic reactions, undergo blue light-promoted bond weakening leading to mild and efficient homolytic cleavage of strong Pd(ii)-C(sp3) bonds under ambient conditions. The origin of light-triggered radical formation in these systems, which lack an obvious ligand-based chromophore (i.e., π-systems), was investigated using a combination of DFT calculations, photoactinometry, and transient absorption spectroscopy. The available data suggest T-shaped organopalladium(ii) complexes manifest unusual blue light-accessible Pd-to-C(sp3) transition. The quantum efficiency and excited state lifetime of this process were unexpectedly superior compared to a prototypical (α-diimine)Pd(ii) complex featuring a low-lying, ligand-centered LUMO (π*). These results suggest coordinatively-unsaturated organopalladium(ii) compounds, catalysts in myriad catalytic processes, have untapped potential for one-electron reactivity under visible light excitation.
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Affiliation(s)
- Peter M Waddell
- Department of Chemistry, Princeton University Princeton NJ 08544 USA
| | - Lei Tian
- Department of Chemistry, Princeton University Princeton NJ 08544 USA
| | | | - Lalu Venigalla
- Department of Chemistry, University of Houston Houston TX 77204 USA
| | - Gregory D Scholes
- Department of Chemistry, Princeton University Princeton NJ 08544 USA
| | - Brad P Carrow
- Department of Chemistry, University of Houston Houston TX 77204 USA
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46
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Yang M, Li H, Borse RA, Lin SX, Yuan D. A Nickel Anchored Covalent Organic Framework as Unimolecular Metallaphotocatalyst for Visible Light Driver C-P Bond Coupling Reaction. Chemistry 2023:e202303556. [PMID: 38092708 DOI: 10.1002/chem.202303556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Indexed: 12/22/2023]
Abstract
The urgent need to develop a sustainable and environmentally friendly method for synthesizing organophosphine compounds is underscored by their extensive applications in organic synthesis, coordination chemistry, medicinal chemistry, and photoelectric materials. Metalated covalent organic frameworks (MCOFs), which seamlessly integrate the inherent photo properties of COF with the catalytic capabilities of metal ions, offer an optimal material for efficient transformation of organics sustainably. In this study, we introduce a simple COF with nickel anchorages (Bpy-COF-NiCl2 ) as a unimolecular metallaphotocatalytic system for effective C-P bond formation. This heterogeneous photocatalyst exhibits superior catalytic performance, achieving yields of up to 95 %, and demonstrates broad substrate tolerance and functional group reactivity. Notably, the metallaphotocatalytic system has demonstrated the capability to process aryl bromides to produce the desired product, a feat not previously reported. Finally, the production and reusability test at the gram scale attests to its superior practicality for designing future organic cross-coupling reactions.
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Affiliation(s)
- Manqiang Yang
- College of Chemistry, Fuzhou University, Fuzhou, 350116, China
- State Key Lab of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
| | - Huijie Li
- College of Chemistry, Fuzhou University, Fuzhou, 350116, China
- State Key Lab of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
| | - Rahul Anil Borse
- State Key Lab of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
| | - Shao-Xia Lin
- College of Chemistry, Fuzhou University, Fuzhou, 350116, China
- State Key Lab of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Daqiang Yuan
- College of Chemistry, Fuzhou University, Fuzhou, 350116, China
- State Key Lab of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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47
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Ogawa T, Wenger OS. Nickel(II) Analogues of Phosphorescent Platinum(II) Complexes with Picosecond Excited-State Decay. Angew Chem Int Ed Engl 2023; 62:e202312851. [PMID: 37732725 DOI: 10.1002/anie.202312851] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/22/2023]
Abstract
Square-planar NiII complexes are interesting as cheaper and more sustainable alternatives to PtII luminophores widely used in lighting and photocatalysis. We investigated the excited-state behavior of two NiII complexes, which are isostructural with two luminescent PtII complexes. The initially excited singlet metal-to-ligand charge transfer (1 MLCT) excited states in the NiII complexes decay to metal-centered (3 MC) excited states within less than 1 picosecond, followed by non-radiative relaxation of the 3 MC states to the electronic ground state within 9-21 ps. This contrasts with the population of an emissive triplet ligand-centered (3 LC) excited state upon excitation of the PtII analogues. Structural distortions of the NiII complexes are responsible for this discrepant behavior and lead to dark 3 MC states far lower in energy than the luminescent 3 LC states of PtII compounds. Our findings suggest that if these structural distortions could be restricted by more rigid coordination environments and stronger ligand fields, the excited-state relaxation in four-coordinate NiII complexes could be decelerated such that luminescent 3 LC or 3 MLCT excited states become accessible. These insights are relevant to make NiII fit for photophysical and photochemical applications that relied on PtII until now.
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Affiliation(s)
- Tomohiro Ogawa
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555, Japan
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
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48
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Mörsdorf JM, Ballmann J. Coordination-Induced Radical Generation: Selective Hydrogen Atom Abstraction via Controlled Ti-C σ-Bond Homolysis. J Am Chem Soc 2023; 145:23452-23460. [PMID: 37861658 DOI: 10.1021/jacs.3c05748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
A method for the generation of transient alkyl radicals via homolytic Ti-C bond cleavage was developed by employing a tailor-made organotitanium half-cage complex. In contrast to established metal-mediated radical initiation protocols via thermal or photochemical M-C σ-bond homolysis, radical formation is triggered solely by coordination of a solvent molecule (thf) to a titanium(IV) center. During the reaction, the nonstabilized alkyl radical is formed along with a persistent titanium(III) metalloradical, thus taming the former transient radical (persistent radical effect). Radical coupling and hydrogen atom abstraction (HAT) reactions have been explored not only experimentally but also computationally and by means of kinetic analysis. Exploiting these findings led to the development of selective HAT transformations, for example, with 9,10-dihydroanthracene. Deuterium labeling studies using selectively deuterated alkyls and 9,10-dihydroanthracene-d4 confirmed a radical pathway, which was underpinned by developing a radical-radical cross-coupling reaction for transferring the alkyl radical to a stable Sn-centered radical. To set the stage for an application in organic synthesis, a 5-endo-trig radical cyclization based on our methodology was established, and a dihydroxylated sesquiterpene was thus prepared in high diastereomeric excess.
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Affiliation(s)
- Jean-Marc Mörsdorf
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, D-69120 Heidelberg, Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, D-69120 Heidelberg, Germany
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49
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Gao J, He XC, Liu YL, Ye ZP, Guan JP, Chen K, Xiang HY, Yang H. Photoredox/Nickel Dual Catalysis-Enabled Cross-Dehydrogenative C-H Amination of Indoles with Unactivated Amine. Org Lett 2023; 25:7716-7720. [PMID: 37842950 DOI: 10.1021/acs.orglett.3c03073] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Herein, a direct cross-dehydrogenative C-H amination of indoles has been successfully achieved, enabled by the merger of photocatalysis with nickel catalysis. This developed process does not require stoichiometric oxidants and prefunctionalization of amine partners, providing a concise platform for C-N bond formation. Moreover, the synthetic practicality of this transformation was well revealed by its high step- and atom-economy, high reaction efficiency, and broad functional group tolerance.
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Affiliation(s)
- Jie Gao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Xian-Chen He
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Yan-Ling Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Zhi-Peng Ye
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Jian-Ping Guan
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Kai Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
| | - Hao-Yue Xiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, Henan, P. R. China
| | - Hua Yang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
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50
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Jaouadi K, Abdellaoui M, Levernier E, Payard PA, Derat E, Le Saux T, Ollivier C, Torelli S, Jullien L, Plasson R, Fensterbank L, Grimaud L. Regime Switch in the Dual-Catalyzed Coupling of Alkyl Silicates with Aryl Bromides. Chemistry 2023; 29:e202301780. [PMID: 37494564 DOI: 10.1002/chem.202301780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 07/28/2023]
Abstract
Metallaphotoredox catalyzed cross-coupling of an arylbromide (Ar-Br) with an alkyl bis(catecholato)silicate (R-Si⊖ ) has been analyzed in depth using a continuum of analytical techniques (EPR, fluorine NMR, electrochemistry, photophysics) and modeling (micro-kinetics and DFT calculations). These studies converged on the impact of four control parameters consisting in the initial concentrations of the iridium photocatalyst ([Ir]0 ), nickel precatalyst ([Ni]0 ) and silicate ([R-Si⊖ ]0 ) as well as light intensity I0 for an efficient reaction between Ar-Br and R-Si⊖ . More precisely, two regimes were found to be possibly at play. The first one relies on an equimolar consumption of Ar-Br with R-Si⊖ smoothly leading to Ar-R, with no side-product from R-Si⊖ and a second one in which R-Si⊖ is simultaneously coupled to Ar-Br and degraded to R-H. This integrative approach could serve as a case study for the investigation of other metallaphotoredox catalysis manifolds of synthetic significance.
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Affiliation(s)
- Khaoula Jaouadi
- LBM, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Mehdi Abdellaoui
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, 75005, Paris, France
| | - Etienne Levernier
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, 75005, Paris, France
| | - Pierre-Adrien Payard
- LBM, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Etienne Derat
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, 75005, Paris, France
| | - Thomas Le Saux
- PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Cyril Ollivier
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, 75005, Paris, France
| | - Stéphane Torelli
- Univ. Grenoble Alpes, CNRS, CEA, IRIG Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, 38054, Grenoble Cedex, France
| | - Ludovic Jullien
- PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Raphaël Plasson
- UMR408 SQPOV Avignon Université/INRAE Campus Jean-Henri Fabre, 301 rue Baruch de Spinoza BP, 21239, 84916, Avignon Cedex 9, France
| | - Louis Fensterbank
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, 75005, Paris, France
| | - Laurence Grimaud
- LBM, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
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