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Gerhards L, Werr M, Hübner O, Solov'yov IA, Himmel HJ. Peculiar Differences between Two Copper Complexes Containing Similar Redox-Active Ligands: Density Functional and Multiconfigurational Calculations. Inorg Chem 2024; 63:961-975. [PMID: 38157840 DOI: 10.1021/acs.inorgchem.3c02949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Transition metal complexes featuring redox-active ligands often exhibit multiple redox states, influenced by the interplay between the metal center and the ligand. This study delves into the electronic structures of two mononuclear complexes of copper with two similar redox-active urea azine ligands. The ligands differ by the replacement of an NCH3 moiety by an S atom in the ligand backbone. Experimental analysis yields pronounced electronic structural disparities between these complexes, observable in both the solution and solid phases. Conventional quantum chemical methods, such as density functional theory using different functionals (B3LYP, TPSSh, and CAM-B3LYP), remain inadequate to rationalize the observed spectroscopic anomalies. However, a multiconfigurational approach elucidates the disparate behaviors of these complexes. Multireference perturbation theory, based on complete active space self-consistent field computations, identifies Cu(I) in the case of the complex with the NCH3 containing ligands and a state with substantial Cu(II) contributions in the case of the complex with the S atom containing ligands. In contrast, DFT indicates Cu(I) in both scenarios.
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Affiliation(s)
- Luca Gerhards
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Street 9-11, Oldenburg 26129, Germany
| | - Marco Werr
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
| | - Olaf Hübner
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Street 9-11, Oldenburg 26129, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg 26111, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von OssietzkyUniversität Oldenburg, Institut Für Physik, Ammerländer Heerstreet 114-118, Oldenburg 26129, Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
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Khan FF, Bera SK, Dey S, Lahiri GK. Redox activity as a tool for bond activations and functionalizations. INORGANIC CHEMISTRY IN INDIA 2023. [DOI: 10.1016/bs.adioch.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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3
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Redox-active ligands for chemical, electrochemical, and photochemical molecular conversions. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Singh K, Kundu A, Adhikari D. Ligand-Based Redox: Catalytic Applications and Mechanistic Aspects. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kirti Singh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Manauli 140306, India
| | - Abhishek Kundu
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Manauli 140306, India
| | - Debashis Adhikari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Manauli 140306, India
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5
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Dhara S, Dey S, Panda S, Lahiri GK. On the Question of S-S Bond Cleavage of 2,2'-Dithiodipyridine on Selective Ru and Os Platforms. MLCT or Hydride or Solvent Mediated Event. Inorg Chem 2022; 61:14297-14312. [PMID: 36044731 DOI: 10.1021/acs.inorgchem.2c01866] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article deals with the S-S bond scission of the model substrate 2,2'-dithiodipyridine (DTDP) in the presence of a selective set of metal precursors: RuII(acac)2, [RuIICl2(PPh3)3], [RuIIHCl(CO)(PPh3)3], [RuII(H)2(CO)(PPh3)3], [RuII(bpy)2Cl2], [RuII(pap)2Cl2], [OsII(bpy)2Cl2], and [OsII(pap)2Cl2] (acac, acetylacetonate; bpy, 2,2'-bipyridine; pap, 2-phenylazopyridine). This led to the eventual formation of the corresponding mononuclear complexes containing the cleaved pyridine-2-thiolate unit in 1-4/[5]ClO4-[8]ClO4. The formation of the complexes was ascertained by their single-crystal X-ray structures, which also established sterically constrained four-membered chelate (average N1-M-S1 angle of 67.89°) originated from the in situ-generated pyridine-2-thiolate unit. Ruthenium(III)-derived one-electron paramagnetic complexes 1-2 (S = 1/2, magnetic moment/B.M. = 1.82 (1)/1.81(2)) exhibited metal-based anisotropic electron paramagnetic resonance (EPR) (Δg: 1/2 = 0.64/0.93, ⟨g⟩: 1/2 = 2.173/2.189) and a broad 1H nuclear magnetic resonance (NMR) signature due to the contact shift effect. The spectroelectrochemical and electronic structural aspects of the complexes were analyzed experimentally in combination with theoretical calculations of density functional theory (DFT and TD-DFT). The unperturbed feature of DTDP even in refluxing ethanol over a period of 10 h can be attributed to the active participation of the metal fragments in facilitating S-S bond cleavage in 1-4/[5]ClO4-[8]ClO4. It also revealed the following three probable pathways toward S-S bond cleavage of DTDP as a function of metal precursors: (i) the metal-to-ligand charge-transfer (MLCT) (RuII → σ* of DTDP)-driven metal oxidation (RuII → RuIII) process in the case of relatively electron-rich metal fragments {RuII(acac)2} or RuIICl2 in 1 or 2, respectively; (ii) metal hydride-assisted formation of 3 or 4 with the concomitant generation of H2; and (iii) S-S bond reduction with the simultaneous oxidation of the solvent benzyl alcohol to benzaldehyde.
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Affiliation(s)
- Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Baeza Cinco MÁ, Wu G, Telser J, Hayton TW. Structural and Spectroscopic Characterization of a Zinc-Bound N-Oxyphthalimide Radical. Inorg Chem 2022; 61:13250-13255. [PMID: 35972238 DOI: 10.1021/acs.inorgchem.2c01765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Thermolysis of a 1:1:1 mixture of MeLH (MeL = {(2,6-iPr2C6H3)NC(Me)}2CH), N-hydroxyphthalimide (HOPth), and diethylzinc in toluene at 77 °C provided [MeLZn(OPth)] (1) in good yield after workup. The subsequent reduction of 1 with 1.3 equiv of KC8 and 1 equiv of 2.2.2-cryptand, in tetrahydrofuran, provided [K(2.2.2-cryptand)][MeLZn(OPth)] (2) in 74% yield after workup. Characterization of 2 via X-ray crystallography and electron paramagnetic resonance spectroscopy reveals the presence of an S = 1/2 radical on the N-oxyphthalimide ligand. Importantly, these data represent the first structural and spectroscopic confirmation of the redox activity of a metal-bound N-oxyphthalimide fragment, expanding the range of structurally characterized redox-active ligands.
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Affiliation(s)
- Miguel Á Baeza Cinco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, 430 South Michigan Avenue. Chicago, Illinois 60605-1394, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93016, United States
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Biswas M, Dey S, Das A, Kanti Paine T, Panda S, Kumar Lahiri G. Dioxygen Activation by Redox-Active Bis(aldimine) Ligand Bridged Diruthenium Complex Possessing Singlet Ground State. Chemistry 2022; 28:e202202088. [PMID: 35947006 DOI: 10.1002/chem.202202088] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Indexed: 01/08/2023]
Abstract
The unexplored 'actor' behavior of redox-active bis(aldimine) congener, p-phenylene-bis(picoline)aldimine (L1), towards dioxygen activation and subsequent functionalization of its backbone was demonstrated on coordination with {Ru(acac)2 } (acac= acetylacetonate). Reaction under aerobic condition led to the one-pot generation of dinuclear complexes with unperturbed L1, imino-carboxamido (L2- ), and bis(carboxamido) (L32- )-bridged isovalent {RuII (μ-L1)RuII }, 1/ {RuIII (μ-L32- )RuIII }, 3 and mixed-valent {RuII (μ-L2- )RuIII }, 2. Authentication of the complexes along with the redox non-innocence behavior of their bridge have been validated through structure, spectroelectrochemistry and DFT calculations. Kinetic and isotope labelling experiments together with DFT analyzed transition states justified the consideration of redox shuttling at metal/L1 interface for 3 O2 activation despite of the closed shell configuration of 1 (S=0) to give carboxamido derived 2/3.
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Affiliation(s)
- Mitrali Biswas
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Abhishek Das
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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Dinda S, Pramanik S, Basu J, Patra SC, Pramanik K, Ganguly S. Azo-oximate metal-carbonyl to metallocarboxylic acid via the intermediate Ir(III) radical congener: quest for co-ligand driven stability of open- and closed-shell complexes. Dalton Trans 2022; 51:10121-10135. [PMID: 35731229 DOI: 10.1039/d2dt00345g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The redox non-innocent behavior of the diaryl-azo-oxime ligand LNOH1 has been accentuated via the synthesis of metastable anion radical complexes of type trans-[Ir(LNO˙-)Cl(CO)(PPh3)2] 2 (CO is trans to azo group of the ligand) by the oxidative coordination reaction of 1 with Vaska's complex. The stereochemical role of co-ligands vis-à-vis the interplay of π-bonding has been found to be decisive in controlling the aptitude of the coordinated redox non-innocent ligand to accept or reject an electron. This has been clarified via the isolation of quite a few complexes as well as the failure to synthesize some others. The oxidized analogues of type trans-[Ir(LNO-)Cl(CO)(PPh3)2]+2+ (CO and azo group of the ligand are trans) as well as its cis isomer cis-[Ir(LNO-)Cl(CO)(PPh3)2]+3+ (CO and azo group of the ligand are cis) have been structurally characterized but the radical anion congener of the latter could not be synthesized. Furthermore, the closed shell complexes [Ir(LNO-)Cl2(PPh3)2] 4 and [Ir(LNO-)2Cl(PPh3)] 5 have been well characterized by diffraction as well as spectral techniques but their corresponding azo anion radical complexes could not be isolated and this is attributed to the trans influence of ancillary ligands. The anion radical complexes trans-[Ir(LNO˙-)Cl(CO)(PPh3)2] 2 may be rapidly transformed to the metallocarboxylic acids trans-[Ir(LNO-)Cl(CO2H)(PPh3)2] 6via a proton-coupled electron transfer (PCET) process, thereby demonstrating the role of odd electron over the coordinated ligand framework to trigger metal-mediated carbonyl to carboxylic acid functionalization. Complexes 6 are further stabilized via intramolecular -CO2H⋯ON- (carboxylic acid⋯oximato) H-bonding. The optoelectronic properties as well as the origin of transitions in the complexes were analyzed by TD-DFT and theoretical analysis, which further disclose that the odd electron in trans-[Ir(LNO˙-)Cl(CO)(PPh3)2] 2 is primarily azo-oxime centric with very low contribution from the iridium center.
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Affiliation(s)
- Soumitra Dinda
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | - Shuvam Pramanik
- Department of Chemistry, Jadavpur University, Kolkata 700032, India
| | - Jaydeep Basu
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | | | | | - Sanjib Ganguly
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
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Mukhopadhyay N, Sengupta A, Vijay AK, Lloret F, Mukherjee R. Ni(II) complexes of a new tetradentate NN'N''O picolinoyl-1,2-phenylenediamide-phenolate redox-active ligand at different redox levels. Dalton Trans 2022; 51:9017-9029. [PMID: 35638812 DOI: 10.1039/d2dt01043g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Three square planar nickel(II) complexes of a new asymmetric tetradentate redox-active ligand H3L2 in its deprotonated form, at three redox levels, open-shell semiquinonate(1-) π radical, quinone(0) and closed-shell dianion of its 2-aminophenolate part, have been synthesized. The coordinated ligand provides N (pyridine) and N' and N'' (carboxamide and 1,2-phenylenediamide, respectively) and O (phenolate) donor sites. Cyclic voltammetry on the parent complex [Ni(L2)] 1 in CH2Cl2 established a three-membered electron-transfer series (oxidative response at E1/2 = 0.57 V and reductive response at -0.32 V vs. SCE) consisting of neutral, monocationic and monoanionic [Ni(L2)]z (z = 0, 1+ and 1-). Oxidation of 1 with AgSbF6 affords [Ni(L2)](SbF6) (2) and reduction of 1 with cobaltocene yields [Co(η5-C5H5)2][Ni(L2)] (3). The molecular structures of 1·CH3CN, 2·0.5CH2Cl2 and 3·C6H6 have been determined by X-ray crystallography at 100 K. Characterization by 1H NMR, X-band EPR (gav = 2.006 (solid); 2.008 (CH2Cl2-C6H5CH3 glass); 80 K) and UV-VIS-NIR spectral properties established that 1, 2 and 3 have [NiII{(L2)˙2-}], [NiII{(L2)-}]+/1+ and [NiII{(L2)3-}]-/1- electronic states, respectively. Thus, the redox processes are ligand-centred. While 1 possesses paramagnetic St (total spin) = 1/2, 2 and 3 possess diamagnetic ground-state St = 0. Interestingly, the variable-temperature (2-300 K) magnetic measurement reveals that 1 with the St = 1/2 ground state attains the antiferromagnetic St = 0 state at a very low temperature, due to weak noncovalent interactions via π-π stacking. Density functional theory (DFT) electronic structural calculations at the B3LYP level of theory rationalized the experimental results. In the UV-VIS-NIR spectra, broad absorptions are recorded for 1 and 2 in the range of 800-1600 nm; however, such an absorption is absent for 3. Time-dependent (TD)-DFT calculations provide a very good fit with the experimental spectra and allow us to identify the observed electronic transitions.
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Affiliation(s)
- Narottam Mukhopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741 246, India
| | - Arunava Sengupta
- Department of Chemistry, Techno India University, West Bengal, Kolkata 700091, India
| | - Aswin Kottapurath Vijay
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741 246, India
| | - Francesc Lloret
- Departament de Química Inorgànica/Instituto de Ciencia Molecular (ICMOL), Universitat de València, Polígono de la Coma, s/n, 46980 Paterna, València, Spain
| | - Rabindranath Mukherjee
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India.
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Chapovetsky A, Kennedy RM, Witzke R, Wegener EC, Dogan F, Patel P, Ferrandon M, Niklas J, Poluektov OG, Rui N, Senanayake SD, Rodriguez JA, Zaluzec NJ, Yu L, Wen J, Johnson C, Jenks CJ, Kropf AJ, Liu C, Delferro M, Kaphan DM. Lithium-Ion Battery Materials as Tunable, “Redox Non-Innocent” Catalyst Supports. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alon Chapovetsky
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Robert M. Kennedy
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ryan Witzke
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Evan C. Wegener
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Fulya Dogan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Prajay Patel
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Magali Ferrandon
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jens Niklas
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Oleg G. Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ning Rui
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Sanjaya D. Senanayake
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - José A. Rodriguez
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Nestor J. Zaluzec
- Photon Sciences Directorate, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Lei Yu
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jianguo Wen
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Christopher Johnson
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Cynthia J. Jenks
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - A. Jeremy Kropf
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Cong Liu
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Massimiliano Delferro
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David M. Kaphan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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Pashanova KI, Poddel'sky AI, Piskunov AV. Complexes of “late” transition metals of the 3d row based on functionalized o-iminobenzoquinone type ligands: Interrelation of molecular and electronic structure, magnetic behaviour. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214399] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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12
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Ali A, Bhowmik S, Barman SK, Mukhopadhyay N, Glüer Nee Schiewer CE, Lloret F, Meyer F, Mukherjee R. Iron(III) Complexes of a Hexadentate Thioether-Appended 2-Aminophenol Ligand: Redox-Driven Spin State Switchover. Inorg Chem 2022; 61:5292-5308. [PMID: 35312298 DOI: 10.1021/acs.inorgchem.1c03992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A green complex [Fe(L3)] (1), supported by the deprotonated form of a hexadentate noninnocent redox-active thioether-appended 2-aminophenolate ligand (H4L3 = N,N'-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2'-diamino(diphenyldithio)ethane), has been synthesized and structurally characterized at 100(2) K and 298(2) K. In CH2Cl2, 1 displays two oxidative and a reductive one-electron redox processes at E1/2 values of -0.52 and 0.20 V, and -0.85 V versus the Fc+/Fc redox couple, respectively. The one-electron oxidized 1+ and one-electron reduced 1- forms, isolated as a blackish-blue solid 1(PF6)·CH2Cl2 (2) and a gray solid [Co(η5-C5H5)2]1·DMF (3), have been structurally characterized at 100(2) K. Structural parameters at 100 K of the ligand backbone and metrical oxidation state values unambiguously establish the electronic states as [FeIII{(LAPO,N)2-}{(LISQO,N)•-}{(LS,S)0}] (1) (two tridentate halves are electronically asymmetric-ligand mixed-valency), [FeIII{(LISQO,N)•-}{(LISQO,N)•-}{(LS,S)0}]+ (1+), and [FeIII{(LAPO,N)2-}{(LAPO,N)2-}{(LS,S)0}]- (1-) [dianionic 2-amidophenolate(2-) (LAPO,N)2- and monoanionic 2-iminobenzosemiquinonate(1-) π-radical (Srad = 1/2) (LISQ)•- redox level]. Mössbauer spectral data of 1 at 295, 200, and 80 K reveal that it has a major low-spin (ls)-Fe(III) and a minor ls-Fe(II) component (redox isomers), and at 7 K, the major component exists exclusively. Thus, in 1, the occurrence of a thermally driven valence-tautomeric (VT) equilibrium (asymmetric) [FeIII{(LAPO,N)2-}{(LISQO,N)•-}{(LS,S)0}] ⇌ (symmetric) [FeII{(LISQO,N)•-}{(LISQO,N)•-}{(LS,S)0}] (80-295 K) is implicated. Mössbauer spectral parameters unequivocally establish that 1+ is a ls-Fe(III) complex. In contrast, the monoanion 1- contains a high-spin (hs)-Fe(III) center (SFe = 5/2), as is deduced from its Mössbauer and EPR spectra. Complexes 1-3 possess total spin ground states St = 0, 1/2, and 5/2, respectively, based on 1H NMR and EPR spectra, the variable-temperature (2-300 K) magnetic behavior of 2, and the μeff value of 3 at 300 K. Broken-symmetry density functional theory (DFT) calculations at the B3LYP-level of theory reveal that the unpaired electron in 1+/2 is due to the (LISQ)•- redox level [ls-Fe(III) (SFe = 1/2) is strongly antiferromagnetically coupled to one of the (LISQ)•- radicals (Srad = 1/2)], and 1-/3 is a hs-Fe(III) complex, supported by (L3)4- with two-halves in the (LAP)2- redox level. Complex 1 can have either a symmetric or asymmetric electronic state. As per DFT calculation, the former state is stabilized by -3.9 kcal/mol over the latter (DFT usually stabilizes electronically symmetric structure). Time-dependent (TD)-DFT calculations shed light on the origin of observed UV-vis-NIR spectral absorptions for 1-3 and corroborate the results of spectroelectrochemical experiments (300-1100 nm) on 1 (CH2Cl2; 298 K). Variable-temperature (218-298 K; CH2Cl2) absorption spectral (400-1000 nm) studies on 1 justify the presence of VT equilibrium in the solution-state.
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Affiliation(s)
- Akram Ali
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Saumitra Bhowmik
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Suman K Barman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Narottam Mukhopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | | | - Francesc Lloret
- Departament de Quımíca, Inorgànica/Instituto de Ciencia Molecular (ICMOL), Universitat de Valeńcia, Polígono de la Coma, s/n, Paterna, València 46980, Spain
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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Greb L. Valence Tautomerism of p‐Block Element Compounds – An Eligible Phenomenon for Main Group Catalysis? Eur J Inorg Chem 2021; 2022:e202100871. [PMID: 35910784 PMCID: PMC9306562 DOI: 10.1002/ejic.202100871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/12/2021] [Indexed: 01/03/2023]
Abstract
Valence tautomerism has had a remarkable impact on several branches of transition metal chemistry. By switching between different valence tautomeric states, physicochemical properties and reactivities can be triggered reversibly. Is this phenomenon transferrable into the p‐block – or is it already happening there? This Perspective collects observations of p‐block element‐ligand systems that might be assignable to valence tautomerism. Further, it discusses occurrences in p‐block element compounds that exhibit the related effect of redox‐induced electron transfer. As disclosed, the concept of valence tautomerism with p‐block elements is at a very early stage. However, given the substantial disparity in the properties of those elements in different redox states, it might offer a valid extension for future developments in main group catalysis.
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Affiliation(s)
- Lutz Greb
- Anorganische Chemie Freie Universität Berlin Fabeckstr. 34–36 14195 Berlin Germany
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
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14
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Switchover from NiIIN2O2 to NiIIN2O2S2 coordination triggered by the redox behaviour of a non-innocent 2-aminophenolate ligand. J CHEM SCI 2021. [DOI: 10.1007/s12039-021-01961-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Wang P, Saber MR, VanNatta PE, Yap GPA, Popescu CV, Scarborough CC, Kieber-Emmons MT, Dunbar KR, Riordan CG. Molecular and Electronic Structures and Single-Molecule Magnet Behavior of Tris(thioether)-Iron Complexes Containing Redox-Active α-Diimine Ligands. Inorg Chem 2021; 60:6480-6491. [PMID: 33840189 DOI: 10.1021/acs.inorgchem.1c00214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Incorporating radical ligands into metal complexes is one of the emerging trends in the design of single-molecule magnets (SMMs). While significant effort has been expended to generate multinuclear transition metal-based SMMs with bridging radical ligands, less attention has been paid to mononuclear transition metal-radical SMMs. Herein, we describe the first α-diiminato radical-containing mononuclear transition metal SMM, namely, [κ2-PhTttBu]Fe(AdNCHCHNAd) (1), and its analogue [κ2-PhTttBu]Fe(CyNCHCHNCy) (2) (PhTttBu = phenyltris(tert-butylthiomethyl)borate, Ad = adamantyl, and Cy = cyclohexyl). 1 and 2 feature nearly identical geometric and electronic structures, as shown by X-ray crystallography and electronic absorption spectroscopy. A more detailed description of the electronic structure of 1 was obtained through EPR and Mössbauer spectroscopies, SQUID magnetometry, and DFT, TD-DFT, and CAS calculations. 1 and 2 are best described as high-spin iron(II) complexes with antiferromagnetically coupled α-diiminato radical ligands. A strong magnetic exchange coupling between the iron(II) ion and the ligand radical was confirmed in 1, with an estimated coupling constant J < -250 cm-1 (J = -657 cm-1, DFT). Calibrated CAS calculations revealed that the ground-state Fe(II)-α-diiminato radical configuration has significant ionic contributions, which are weighted specifically toward the Fe(I)-neutral α-diimine species. Experimental data and theoretical calculations also suggest that 1 possesses an easy-axis anisotropy, with an axial zero-field splitting parameter D in the range from -4 to-1 cm-1. Finally, dynamic magnetic studies show that 1 exhibits slow magnetic relaxation behavior with an energy barrier close to the theoretical maximum, 2|D|. These results demonstrate that incorporating strongly coupled α-diiminato radicals into mononuclear transition metal complexes can be an effective strategy to prepare SMMs.
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Affiliation(s)
- Peng Wang
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Mohamed R Saber
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States.,Department of Chemistry, Fayoum University, Fayoum 63514, Egypt
| | - Peter E VanNatta
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Glenn P A Yap
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Codrina V Popescu
- Department of Chemistry, University of Saint Thomas, 2115 Summit Avenue, Saint Paul, Minnesota 55105, United States
| | - Christopher C Scarborough
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States.,Syngenta Crop Protection AG, Schaffhauserstrasse, CH-4332 Stein, Switzerland
| | | | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Charles G Riordan
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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16
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Khan FF, Mondal S, Chandra S, Neuman NI, Sarkar B, Lahiri GK. On the non-innocence and reactive versus non-reactive nature of α-diketones in a set of diruthenium frameworks. Dalton Trans 2021; 50:1106-1118. [DOI: 10.1039/d0dt03400b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Slightly modified ligand designs in diruthenium setups have major impacts on the reactivity/stability of coordination complexes. The 1,2-bis(2-hydroxyphenyl)ethane-1,2-dione bridge is also potentially redox non-innocent.
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Affiliation(s)
- Farheen Fatima Khan
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai-400076
- India
| | - Saikat Mondal
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai-400076
- India
| | - Shubhadeep Chandra
- Lehrstuhl für Anorganische Koordinaitonschemie
- Institut für Anorganische Chemie
- Universität Stuttgart
- D-70550 Stuttgart
- Germany
| | - Nicolas I. Neuman
- Lehrstuhl für Anorganische Koordinaitonschemie
- Institut für Anorganische Chemie
- Universität Stuttgart
- D-70550 Stuttgart
- Germany
| | - Biprajit Sarkar
- Lehrstuhl für Anorganische Koordinaitonschemie
- Institut für Anorganische Chemie
- Universität Stuttgart
- D-70550 Stuttgart
- Germany
| | - Goutam Kumar Lahiri
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai-400076
- India
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17
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Kumari M, Bera SK, Lahiri GK. Noninnocence of the deprotonated 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine bridge in diruthenium frameworks - a function of co-ligands. Dalton Trans 2021; 50:9891-9903. [PMID: 34196336 DOI: 10.1039/d1dt01488a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The article deals with the sensitive electronic forms in accessible redox states of structurally and spectroscopically authenticated deprotonated 1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = H) or 1,2-bis((3,5-dimethyl-1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = Me), a BODIPY analogue bridged diruthenium complex as a function of varying ancillary ligands. It involved rac-(acac)2RuIII(μ-LR 2-)RuIII(acac)21a, R = H; 1b, R = Me (S = 1, acac = acetylacetonate), rac-[(bpy)2RuII(μ-L2-)RuII(bpy)2](ClO4)2 [2](ClO4)2 (S = 0, bpy = 2,2'-bipyridine) and diastereomeric [(pap)2RuII(μ-L2-)RuII(pap)2](ClO4)2meso-[3a](ClO4)2/rac-[3b](ClO4)2 (S = 0, pap = phenylazopyridine). The crystal structure established the linkage of the conjugated -C5[double bond, length as m-dash]N2-N3[double bond, length as m-dash]C6- central unit with the two terminal deprotonated pyrrole units of coordinated L2-. The bridging L2- in 1a, 1b, [2](ClO4)2, [3b](ClO4)2 and [3a](ClO4)2 was slightly twisted and planar with torsional angles of 41.54°, 42.91°, 37.38°, 35.33° and 0°, respectively, with regard to the central N2-N3 bond. The extent of twisting of the bridge followed an inverse relationship with the RuRu separation: 4.935/4.934 Å 1a/1b < 5.141 Å [2](ClO4)2 < 5.201 Å [3b](ClO4)2 < 5.351 Å [3a](ClO4)2. This is also attributed to the intermolecular ππ/CHπ interactions between the nearby aromatic rings of L and bpy or pap in [2](ClO4)2 or [3](ClO4)2, respectively. The multiple redox steps of the complexes varied appreciably based on the σ-donating (acac) and π-acidic (bpy, pap) characteristics of the ancillary ligands. Experimental (structure, EPR) and theoretical (DFT) evaluation pertaining to the electronic forms of 1n, 2n and 3n demonstrated the preferential involvement of L based frontier orbitals in electron transfer processes even in combination with the redox facile ruthenium ion. This in turn highlighted its redox non-innocent feature as in the case of well-documented metal coordinated quinonoid, formazanate, diimine (bpy), azo (pap) and β-diketiminate functions.
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Affiliation(s)
- Maya Kumari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
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18
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Chatterjee B, Chang W, Werlé C. Molecularly Controlled Catalysis – Targeting Synergies Between Local and Non‐local Environments. ChemCatChem 2020. [DOI: 10.1002/cctc.202001431] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Basujit Chatterjee
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
| | - Wei‐Chieh Chang
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
| | - Christophe Werlé
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
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19
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Chegerev MG, Arsenyeva KV, Cherkasov AV, Piskunov AV. Specific Features of EPR Spectroscopy of Organotin Compounds with Paramagnetic Ligands of the o-Iminobenzosemiquinone Type. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s1070328420110019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Chatterjee B, Chang WC, Jena S, Werlé C. Implementation of Cooperative Designs in Polarized Transition Metal Systems—Significance for Bond Activation and Catalysis. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03794] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Basujit Chatterjee
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Wei-Chieh Chang
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Soumyashree Jena
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Christophe Werlé
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
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21
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Ershova IV, Piskunov AV, Cherkasov VK. Complexes of diamagnetic cations with radical anion ligands. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4957] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Dey S, Panda S, Lahiri GK. Ruthenium-Hydride Assisted Remarkable Diversity Towards Non-Spectator Feature of Benzodifuroxan. Chem Asian J 2020; 15:3281-3295. [PMID: 32779852 DOI: 10.1002/asia.202000849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/09/2020] [Indexed: 11/07/2022]
Abstract
The present article demonstrates that ruthenium-hydride [RuII (H)(Cl)(CO)(PPh3 )3 ] mediated diverse functionalization modes of benzodifuroxan (BDF) encompassing two furoxan rings. Hydride transfer from the metal precursor facilitated multiple cascade reactions involving unsymmetrical cleavage of the furoxan rings of BDF, leading to the one-pot formation of a series of ruthenium (II) coordinated functionalized ligands exhibiting bidentate κ2 -N,O, κ2 -N,N' and bis-bidentate μ-bis(κ2 -N,O) modes. Further, a moderately stable intermediate species was also encountered in the reaction sequence in which the transformed deoxygenated ligand coordinated to the metal ion via the rarely manifested furazan ring (κ2 -N,N'' mode). The products were authenticated by their single-crystal X-ray structures and other spectroscopic/analytical techniques. Redox non-innocence of the functionalized ligands in the complexes was illustrated by spectroelectrochemistry (cyclic voltammmetry, UV-Vis. and EPR) in conjunction with DFT/TD-DFT calculations. Mechanistic outline for the facile ring opening processes of BDF including interconversions of complexes (e. g. reductive ring opening) were also addressed.
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Affiliation(s)
- Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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23
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Witzke RJ, Chapovetsky A, Conley MP, Kaphan DM, Delferro M. Nontraditional Catalyst Supports in Surface Organometallic Chemistry. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03350] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan J. Witzke
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Alon Chapovetsky
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Matthew P. Conley
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - David M. Kaphan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Massimiliano Delferro
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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