1
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Yamada T, Shimizu D, Matsuda K. Oxidation of Weakly Interacting Diradicals: An Approach for Strong and Tunable Near-Infrared-Absorbing Dyes Based on Small Chromophores. J Phys Chem Lett 2024; 15:9175-9182. [PMID: 39213498 DOI: 10.1021/acs.jpclett.4c02212] [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
Near-infrared (NIR)-absorbing dyes are valuable for various applications, such as bioimaging and electronic devices. This work introduces a novel approach for designing NIR dyes, oxidation of weakly coupled diradicals. Our approach features a weak exchange interaction in diradicals, which potentially leads to bonding/antibonding molecular orbitals with a small energy gap. We found that removing one of two singly occupied molecular orbital electrons of the diradicals results in an exceptionally narrow frontier orbital energy gap. We examined a series of Blatter radical dimers, and the most weakly coupled diradical prepared in this work (ΔEST ∼ 0.12 eV) with a molecular weight of 590 Da exhibited a strong NIR absorption band reaching 2200 nm upon one-electron oxidation. The optical band gaps of the radical cations strongly correlate to the exchange interaction in the precursor neutral species, offering prediction and fine-tuning of the optical band gap in the NIR region.
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Affiliation(s)
- Takeru Yamada
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Daiki Shimizu
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kenji Matsuda
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
- Fukui Institute for Fundamental Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-8103, Japan
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2
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Anthony Raj MR, Yao C, Frémont M, Skene WG. Exploiting Mixed Valence Charge Transfer for Electrochromic and Electrofluorochromic Use. Chemistry 2024; 30:e202401417. [PMID: 38970532 DOI: 10.1002/chem.202401417] [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: 04/11/2024] [Indexed: 07/08/2024]
Abstract
An asymmetric mixed valence fluorophore with two different electron rich termini was investigated as a dual-role active material for electrochromism and electrofluorochromism. The fluorescence quantum yield (Φfl) and emission wavelength of the fluorophore were dependent on solvent polarity. The quantum yield of the material in an electrolyte gel, on a glass substrate and in a device was 40 %, 20 % and 13 % respectively. The fluorophore further underwent two near-simultaneous electrochemical oxidations. The first oxidation resulted in a 1000 nm red shift in the absorption to broadly absorb in the NIR, corresponding to the intervalence charge transfer (IVCT). Whereas the second oxidation led to a perceived green color at 715 nm with the extinction of the NIR absorbing IVCT. Owing to the dissymmetry of the fluorophore along with its two unique oxidation sites, the IVCT gives rise to a mixed valence transfer charge (MVCT). The coloration efficiency of the fluorophore in both solution and a device was 1433 and 200 cm2 C-1, respectively. The fluorescence intensity could be reversibly modulated electrochemically. The photoemission intensity of the fluorophore was modulated with applied potential in an operating electrochromic/electrofluorochromic device. Both the dual electrochromic and the electrofluorochromic behavior of the fluorophore were demonstrated.
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Affiliation(s)
- Mohan Raj Anthony Raj
- Laboratoire de caractérisation photophysique des matériaux conjugués, Département de Chimie, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C 3J7, Canada
| | - Chengzhang Yao
- Laboratoire de caractérisation photophysique des matériaux conjugués, Département de Chimie, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C 3J7, Canada
| | - Mathieu Frémont
- Laboratoire de caractérisation photophysique des matériaux conjugués, Département de Chimie, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C 3J7, Canada
| | - W G Skene
- Laboratoire de caractérisation photophysique des matériaux conjugués, Département de Chimie, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C 3J7, Canada
- Institut Courtois, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C 3J7, Canada
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3
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Puerta Lombardi BM, Faas MR, West D, Suvinen RA, Tuononen HM, Roesler R. An isolable, chelating bis[cyclic (alkyl)(amino)carbene] stabilizes a strongly bent, dicoordinate Ni(0) complex. Nat Commun 2024; 15:3417. [PMID: 38653986 DOI: 10.1038/s41467-024-47036-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Chelating ligands have had a tremendous impact in coordination chemistry and catalysis. Notwithstanding their success as strongly σ-donating and π-accepting ligands, to date no chelating bis[cyclic (alkyl)(amino)carbenes] have been reported. Herein, we describe a chelating, C2-symmetric bis[cyclic (alkyl)(amino)carbene] ligand, which was isolated as a racemic mixture. The isolation and structural characterization of its isostructural, pseudotetrahedral complexes with iron, cobalt, nickel, and zinc dihalides featuring eight-membered metallacycles demonstrates the binding ability of the bis(carbene). Reduction of the nickel(II) dibromide with potassium graphite produces a dicoordinate nickel(0) complex that features one of the narrowest angles measured in any unsupported dicoordinate transition metal complexes.
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Affiliation(s)
| | - Morgan R Faas
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada
| | - Daniel West
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada
| | - Roope A Suvinen
- Department of Chemistry, NanoScience Centre, University of Jyvӓskylӓ, Jyvӓskylӓ, Finland
| | - Heikki M Tuononen
- Department of Chemistry, NanoScience Centre, University of Jyvӓskylӓ, Jyvӓskylӓ, Finland.
| | - Roland Roesler
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada.
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4
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Mao X, Qiu S, Guo R, Dai Y, Zhang J, Kong L, Xie Z. Cyclic (Alkyl)(Amino)Carbene-Iminoboryl Compounds with Three Formal Oxidation States. J Am Chem Soc 2024; 146:10917-10924. [PMID: 38587904 DOI: 10.1021/jacs.4c01934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
BN/CC isosterism is an effective strategy to build hybrid functional molecules with unique properties. In contrast to the alkynyl iminium salts derived from cyclic (alkyl)(amino)carbenes (CAACs) that feature only one reversible reduction wave, the isoelectronic cationic CAAC-iminoboryl adducts could be singly and doubly reduced smoothly. Both the resultant neutral radical and anionic azaborataallenes bear NBC-mixed allenic structures. The former radical has a high spin-density of 0.55e at CCAAC carbon, yet exhibits formal boron-centered radical reactivity. The latter azaborataallenes feature the nucleophilic CCAAC center and polar N(δ-)═B(δ+)═C(δ-) unit, and readily undergo nucleophilic substitution, isocyanide insertion, dipolar addition and cycloaddition reactions etc. The N-substituents have been shown to have a significant influence on the solid-state structure, thermal stability, and reactivity of azaborataallenes. This work showcases the allenic BN-unsaturated species as versatile building blocks in organic synthesis.
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Affiliation(s)
- Xiaofeng Mao
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
| | - Shuang Qiu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Rui Guo
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yuyang Dai
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jie Zhang
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
| | - Lingbing Kong
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
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5
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Nayak MK, Elvers BJ, Mehta S, Krummenacher I, Mondal A, Braunschweig H, Schulzke C, Ravat P, Jana A. Bis-[cyclic(alkyl)(amino)carbene]-derived diradicals. Chem Commun (Camb) 2024; 60:1739-1742. [PMID: 38240479 DOI: 10.1039/d3cc05779h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Crystalline polymeric structures of trans-1,4-cyclohexylene bridged N-tethered bis-CAACs in the form of their LiOTf adducts were synthesized and isolated. These were further used as building blocks for the synthesis of crystalline (amino)(carboxy)-based diradicals. The triplet diradical character of these compounds was unambiguously confirmed by the presence of a half-field signal in their EPR spectra. Theoretical calculations show that the singlet state is marginally more stable than the triplet state.
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Affiliation(s)
- Mithilesh Kumar Nayak
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, India.
| | - Benedict J Elvers
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, D-17489, Greifswald, Germany.
| | - Sakshi Mehta
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India.
| | - Ivo Krummenacher
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Abhishake Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India.
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, D-17489, Greifswald, Germany.
| | - Prince Ravat
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, India.
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6
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Kessler BJO, Mansoor IF, Wozniak DI, Emge TJ, Lipke MC. Controlling Intramolecular and Intermolecular Electronic Coupling of Radical Ligands in a Series of Cobaltoviologen Complexes. J Am Chem Soc 2023; 145:15924-15935. [PMID: 37460450 DOI: 10.1021/jacs.3c03725] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Controlling electronic coupling between multiple redox sites is of interest for tuning the electronic properties of molecules and materials. While classic mixed-valence (MV) systems are highly tunable, e.g., via the organic bridges connecting the redox sites, metal-bridged MV systems are difficult to control because the electronics of the metal cannot usually be altered independently of redox-active moieties embedded in its ligands. Herein, this limitation was overcome by varying the donor strengths of ancillary ligands in a series of cobalt complexes without directly perturbing the electronics of viologen-like redox sites bridged by the cobalt ions. The cobaltoviologens [1X-Co]n+ feature four 4-X-pyridyl donor groups (X = CO2Me, Cl, H, Me, OMe, NMe2) that provide gradual electronic tuning of the bridging CoII centers, while a related complex [2-Co]n+ with NHC donors supports exclusively CoIII states even upon reduction of the viologen units. Electrochemistry and IVCT band analysis indicate that the MV states of these complexes have electronic structures ranging from fully localized ([2-Co]4+; Robin-Day Class I) to fully delocalized ([1CO2Me-Co]3+; Class III) descriptions, demonstrating unprecedented control over electronic coupling without changing the identity of the redox sites or bridging metal. Additionally, single-crystal XRD characterization of the homovalent complexes [1H-Co]2+ and [1H-Zn]2+ revealed radical-pairing interactions between the viologen ligands of adjacent complexes, representing a type of through-space electronic coupling commonly observed for organic viologen radicals but never before seen in metalloviologens. The extended solid-state packing of these complexes produces 3D networks of radical π-stacking interactions that impart unexpected mechanical flexibility to these crystals.
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Affiliation(s)
- Brice J O Kessler
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Iram F Mansoor
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Derek I Wozniak
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Thomas J Emge
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Mark C Lipke
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, United States
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7
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Peltier JL, Serrato MR, Thery V, Pecaut J, Tomás-Mendivil E, Bertrand G, Jazzar R, Martin D. An air-stable radical with a redox-chameleonic amide. Chem Commun (Camb) 2023; 59:595-598. [PMID: 36524847 DOI: 10.1039/d2cc05404c] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An air-stable (amino)(amido)radical was synthesized by reacting a cyclic (alkyl)(amino)carbene with carbazoyl chloride, followed by one-electron reduction. We show that an adjacent radical center weakens the amide bond. It enables the amino group to act as a strong acceptor under steric contraint, thus enhancing the stabilizing capto-dative effect.
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Affiliation(s)
- Jesse L Peltier
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - Melinda R Serrato
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - Valentin Thery
- University Grenoble Alpes, CNRS, DCM, Grenoble 38000, France.
| | - Jacques Pecaut
- University Grenoble Alpes, CEA, CNRS, INAC-SyMMES, UMR 5819, Grenoble 38000, France
| | | | - Guy Bertrand
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Chemistry Laboratory (IRL 3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, USA
| | - David Martin
- University Grenoble Alpes, CNRS, DCM, Grenoble 38000, France.
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8
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Nayak MK, Sarkar P, Elvers BJ, Mehta S, Zhang F, Chrysochos N, Krummenacher I, Vijayakanth T, Narayanan RS, Dolai R, Roy B, Malik V, Rawat H, Mondal A, Boomishankar R, Pati SK, Braunschweig H, Schulzke C, Ravat P, Jana A. A bis-NHC-CAAC dimer derived dicationic diradical. Chem Sci 2022; 13:12533-12539. [PMID: 36382295 PMCID: PMC9629079 DOI: 10.1039/d2sc03937k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/21/2022] [Indexed: 08/11/2023] Open
Abstract
The isolation of carbon-centered diradicals is always challenging due to synthetic difficulties and their limited stability. Herein we report the synthesis of a trans-1,4-cyclohexylene bridged bis-NHC-CAAC dimer derived thermally stable dicationic diradical. The diradical character of this compound was confirmed by EPR spectroscopy. The variable temperature EPR study suggests the singlet state to be marginally more stable than the triplet state (2J = -5.5 cm-1 (ΔE ST = 0.065 kJ mol-1)). The presence of the trans-1,4-cyclohexylene bridge is instrumental for the successful isolation of this dicationic diradical. Notably, in the case of ethylene or propylene bridged bis-NHC-CAAC dimers, the corresponding dicationic diradicals are transient and rearrange to hydrogen abstracted products.
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Affiliation(s)
| | - Pallavi Sarkar
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bangalore-560064 India
| | - Benedict J Elvers
- Institut für Biochemie, Universität Greifswald Felix-Hausdorff-Straße 4 D-17489, Greifswald Germany
| | - Sakshi Mehta
- Solid State and Structural Chemistry Unit, Indian Institute of Science Bangalore 560012 India
| | - Fangyuan Zhang
- Institute of Organic Chemistry, University of Würzburg Am Hubland 97074 Würzburg Germany
| | - Nicolas Chrysochos
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad-500107 India
| | - Ivo Krummenacher
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Thangavel Vijayakanth
- Department of Chemistry, Indian Institute of Science Education and Research Pune Dr Homi Bhabha Road Pune 411008 India
| | | | - Ramapada Dolai
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad-500107 India
| | - Biswarup Roy
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad-500107 India
| | - Vishal Malik
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad-500107 India
| | - Hemant Rawat
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad-500107 India
| | - Abhishake Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science Bangalore 560012 India
| | - Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research Pune Dr Homi Bhabha Road Pune 411008 India
| | - Swapan K Pati
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bangalore-560064 India
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald Felix-Hausdorff-Straße 4 D-17489, Greifswald Germany
| | - Prince Ravat
- Institute of Organic Chemistry, University of Würzburg Am Hubland 97074 Würzburg Germany
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad-500107 India
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9
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Tanaka Y, Kawano R, Akita M. Acene Size-Dependent Transition of The Radical Centers From the Metal to The Acene Parts In Monocationic Dinuclear (Diethynylacene)diyl Complexes. Chemistry 2022; 28:e202201358. [PMID: 35680560 PMCID: PMC9804824 DOI: 10.1002/chem.202201358] [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: 05/03/2022] [Indexed: 01/09/2023]
Abstract
Controlling radical localization/delocalization is important for functional materials. The present paper describes synthesis and results of electrochemical, spectroscopic, and theoretical studies of diruthenium (p-diethynylacene)diyl complexes, Me3 Si-(C≡C)2 -Ru(dppe)2 -C≡C-Ar-C≡C-Ru(dppe)2 -(C≡C)2 -SiMe3 (1-6) (dppe: 1,2-bis(diphenylphosphino)ethane), and their monocationic radical species ([1]+ -[6]+ ). The HOMO-LUMO energy gaps can be finely tuned by the acene rings in the bridging ligands installed, as indicated by the absorption maxima of the electronic spectra of 1-6 ranging from the UV region even to the NIR region. The cationic species [1]+ -[6]+ show two characteristic NIR bands, which are ascribed to the charge resonance (CR) and π-π* transition bands, as revealed by spectroelectrochemistry. Expansion of the acene rings in [1]+ -[6]+ causes (1) blue shifts of the CR bands and red shifts of the π-π* transition bands and (2) charge localization on the acene parts as evidenced by the ESR, DFT and TD-DFT analyses. Notably, the monocationic complexes of the larger acene derivatives are characterized as the non-classical acene-localized radicals.
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Affiliation(s)
- Yuya Tanaka
- Laboratory for Chemistry and Life ScienceInstitute of Innovative ResearchTokyo Institute of Technology4259 Nagatsuta, Midori-kuYokohama226-8503Japan
- Department of Chemical Science and EngineeringSchool of Materials and Chemical TechnologyTokyo Institute of Technology4259 Nagatsuta, Midori-kuYokohama226-8503Japan
| | - Reo Kawano
- Department of Chemical Science and EngineeringSchool of Materials and Chemical TechnologyTokyo Institute of Technology4259 Nagatsuta, Midori-kuYokohama226-8503Japan
| | - Munetaka Akita
- Laboratory for Chemistry and Life ScienceInstitute of Innovative ResearchTokyo Institute of Technology4259 Nagatsuta, Midori-kuYokohama226-8503Japan
- Department of Chemical Science and EngineeringSchool of Materials and Chemical TechnologyTokyo Institute of Technology4259 Nagatsuta, Midori-kuYokohama226-8503Japan
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10
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Théry V, Molton F, Sirach S, Tillet N, Pécaut J, Tomás-Mendivil E, Martin D. The curious case of a sterically crowded Stenhouse salt. Chem Sci 2022; 13:9755-9760. [PMID: 36091895 PMCID: PMC9400627 DOI: 10.1039/d2sc01895k] [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: 04/01/2022] [Accepted: 07/27/2022] [Indexed: 11/23/2022] Open
Abstract
We report a peculiar Stenhouse salt. It does not evolve into cyclopentenones upon basification, due to the steric hindrance of its bulky stable carbene patterns. This allowed for the observation and characterization of the transient open-chain neutral derivative, which was isolated as its cyclized form. The latter features an unusually long reactive C-O bond (150 pm) and a rich electrochemistry, including oxidation into an air-persistent radical cation.
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Affiliation(s)
| | | | - Selim Sirach
- Univ. Grenoble Alpes, CNRS, DCM Grenoble 38000 France
| | - Neven Tillet
- Univ. Grenoble Alpes, CNRS, DCM Grenoble 38000 France
| | - Jacques Pécaut
- Univ. Grenoble Alpes, CEA, CNRS, INAC-SyMMES, UMR 5819 Grenoble 38000 France
| | | | - David Martin
- Univ. Grenoble Alpes, CNRS, DCM Grenoble 38000 France
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11
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Song H, Pietrasiak E, Lee E. Persistent Radicals Derived from N-Heterocyclic Carbenes for Material Applications. Acc Chem Res 2022; 55:2213-2223. [PMID: 35849761 DOI: 10.1021/acs.accounts.2c00222] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Persistent radicals are potential building blocks of novel materials in many fields. Recently, highly stable persistent radicals are considered to be within reach, thanks to several radical stabilization strategies such as spin delocalization and steric protection. N-Heterocyclic carbene (NHC)-derived substituents can be attached to a radical center for these purposes, as illustrated by numerous NHC-stabilized radicals reported in the last two decades.This Account describes our recent work on developing NHC-derived persistent radicals, as well as their prospective applications. Considering that NHCs not only stabilize radicals but also reversibly interact with gas molecules, in 2015 our group reported NHC-nitric oxide (NHC-NO) radicals produced by reversibly trapping nitric oxide (NO) radical gas in NHCs. The resultant compounds were loaded into biocompatible poly(ethylene glycol)-block-poly(caprolactone) (PEG-b-PCL) micelles and injected into tumor-bearing mice. Then, NO release was triggered by high-intensity focused ultrasound irradiation of the tumor tissue. Furthermore, the NHC-NO radicals could also serve as a platform to generate other organic radicals such as oxime ether or iminyl radicals. Apart from medicine-related applications, radicals stabilized by NHCs can be used as energy storage materials. In this context, the triazenyl radical containing two NHC units reported by our laboratory could be a cathode active material in batteries, as an organic alternative to LiCoO2. The subsequently prepared unsymmetrical triazenyl radical derivatives were applied as anolytes in nonaqueous all-organic redox flow batteries. In addition, a ferrocene-based redox flow battery anolyte was obtained by introducing NHC-derived substituents that effectively stabilize the ferrocenate derivatives previously reported only at low temperatures. The batteries containing NHC-supported radicals exhibited high energy efficiency and insignificant radical decomposition over multiple cycles. Finally, toward developing air-persistent organic radicals for flexible devices and MRI contrasting agents, we also highlight our recent air- and physiologically stable organic radicals derived from NHCs. Coordination of tris(pentafluorophenyl)borane to the NHC-NO radical produced a new radical cation that is stable in an organic solvent under air for several months. The readily accessible 1,2-dicarbonyl radical cations generated by the reaction of NHCs with oxalyl chloride are remarkably persistent even in an aqueous solution for several months. They are also highly stable even under physiological conditions, making them particularly attractive potential candidates for organic MRI contrast agents. We hope that this Account will serve as a guide for the future development of stable NHC-derived organic radicals and draw the attention of the synthetic community to their potential applications in material science.
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Affiliation(s)
- Hayoung Song
- Department of Chemistry, Pohang University of Science and Technology. Pohang, 37673, Republic of Korea
| | - Ewa Pietrasiak
- Department of Chemistry, Pohang University of Science and Technology. Pohang, 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology. Pohang, 37673, Republic of Korea
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12
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Puerta Lombardi BM, Pezoulas ER, Suvinen RA, Harrison A, Dubrawski ZS, Gelfand BS, Tuononen HM, Roesler R. Bis[cyclic (alkyl)(amino)carbene] isomers: Stable trans-bis(CAAC) versus facile olefin formation for cis-bis(CAAC). Chem Commun (Camb) 2022; 58:6482-6485. [PMID: 35583166 DOI: 10.1039/d2cc01476a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isomeric bis(aldiminium) salts with a 1,4-cyclohexylene framework were synthesized. The first isolable bis(CAAC) was prepared from the trans-stereoisomer and its ditopic ligand competency was proven by conversion to iridium(I) and rhodium(I) complexes. Upon deprotonation, the cis-isomer yielded an electron rich olefin via a classic, proton-catalyzed pathway. The CC bond formation from the desired cis-bis(CAAC) was shown to be thermodynamically very favorable and to involve a small activation barrier. Compounds that can be described as insertion products of the cis-bis(CAAC) into the E-H bonds of NH3, CH3CN and H2O were also identified.
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Affiliation(s)
- Braulio M Puerta Lombardi
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
| | - Ethan R Pezoulas
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
| | - Roope A Suvinen
- Department of Chemistry, Nanoscience Centre, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland.
| | - Alexander Harrison
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
| | - Zachary S Dubrawski
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
| | - Benjamin S Gelfand
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
| | - Heikki M Tuononen
- Department of Chemistry, Nanoscience Centre, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland.
| | - Roland Roesler
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
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13
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Zhou K, Zhang YY, Chen XT, Hu SX. 12-Membered Ring Carbides with Stabilization of Actinide Atoms. Inorg Chem 2022; 61:2119-2128. [PMID: 35041785 DOI: 10.1021/acs.inorgchem.1c03341] [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
Actinide (Th and U) carbides as the potential nuclear fuels in nuclear reactors require basic research in order to understand the thermodynamic stability and performance of these substances. Here we report the structural characterization and bonding analyses of [C12], ThC12, and UC12 clusters via a global-minimum search combined with relativistic quantum chemistry calculations to elucidate the stability and bonding nature of An-C bonds. We predict that these [C12], ThC12, and UC12 compounds have a planar structure with C6h, D12h, and D12h symmetry, respectively. [C12] has a hyperconjugation structure containing alternating single and double bonds. The significant stabilization when forming AnC12 predominantly comes from the electrostatic interaction between An4+ and [C12]4- and also from a certain degree of orbital interaction between the An 5f6d7s valence shell and [C12] π orbitals. The covalent character of the An-C bonds exhibits a direct in-plane σ-type overlap of the C 2p-derived MOs of [C12] and the An 5fϕ AO, thus leading to an unprecedented electronic configuration of d1f1 for U in UC12. Our results present an example of the novel properties that can be expected for actinide compounds and would provide the knowledge required to obtain novel structures of AnC12 in future experiments.
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Affiliation(s)
- Ke Zhou
- College of Chemistry and Environmental Science & Shaanxi Key Laboratory of Catalysis & Institute of Theoretical and Computational Chemistry, Shaanxi University of Technology, Hanzhong 723000, China
| | - Yang-Yang Zhang
- Department of Chemistry & Key Laboratory of Organic Optoelectronics, Tsinghua University, Beijing 100084, China
| | - Xiao-Tong Chen
- Institute of Nuclear and New Energy Technology & Collaborative Innovation Center of Advanced Nuclear Energy Technology, Tsinghua University, Beijing 100084, China
| | - Shu-Xian Hu
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, China.,Beijing Computational Science Research Center, Beijing 100193, China
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14
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Cyclic (alkyl)(amino)carbene (CAAC) ligands: Electronic structure and application as chemically- and redox-non-innocent ligands and chromophores. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2022. [DOI: 10.1016/bs.adomc.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Yang YY, Zhu XQ, Wang Y, Wu XT, Sheng TL. Effect of potential difference between the central and terminal metals on the electron communication in an Fe–Ru–Fe cyanidometal-bridged mixed valence system. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00909a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the Fe–Ru–Fe mixed valence system, the change of the donor and accepter can affect potential difference (energy difference) between bridge and terminal redox centers. This change has an effect on the electron communication.
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Affiliation(s)
- Yu-Ying Yang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, 350002 Fuzhou, Fujian, China
| | - Xiao-Quan Zhu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, 350002 Fuzhou, Fujian, China
- Department of Criminal Investigation, Fujian Police College, 350007 Fuzhou, Fujian, China
| | - Yong Wang
- Hubei Key Laboratory of Drug Synthesis and Optimization, College of Chemical Engineering and Pharmacy, Jingchu University of Technology, Jinmen, Hubei 444800, China
| | - Xin-Tao Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, 350002 Fuzhou, Fujian, China
| | - Tian-Lu Sheng
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, 350002 Fuzhou, Fujian, China
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16
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A crystalline radical cation derived from Thiele's hydrocarbon with redox range beyond 1 V. Nat Commun 2021; 12:7052. [PMID: 34862371 PMCID: PMC8642399 DOI: 10.1038/s41467-021-27104-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 11/03/2021] [Indexed: 02/07/2023] Open
Abstract
Thiele’s hydrocarbon occupies a central role as an open-shell platform for new organic materials, however little is known about its redox behaviour. While recent synthetic approaches involving symmetrical carbene substitution of the CPh2 termini yield isolable neutral/dicationic analogues, the intervening radical cations are much more difficult to isolate, due to narrow compatible redox ranges (typically < 0.25 V). Here we show that a hybrid BN/carbene approach allows access to an unsymmetrical analogue of Thiele’s hydrocarbon 1, and that this strategy confers markedly enhanced stability on the radical cation. 1•+ is stable across an exceptionally wide redox range (> 1 V), permitting its isolation in crystalline form. Further single-electron oxidation affords borenium dication 12+, thereby establishing an organoboron redox system fully characterized in all three redox states. We perceive that this strategy can be extended to other transient organic radicals to widen their redox stability window and facilitate their isolation. Organic molecules that can access various redox states have potential applications in electronics, batteries, catalysis, among others. Here the authors report the preparation of an unsymmetrical organoboron analogue of Thiele’s hydrocarbon and study its one- and two-electron oxidation reactions; remarkably, the radical cation is stable over a redox range of > 1 V and can also be isolated.
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17
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Zhao J, Li X, Han YF. Air-/Heat-Stable Crystalline Carbon-Centered Radicals Derived from an Annelated N-Heterocyclic Carbene. J Am Chem Soc 2021; 143:14428-14432. [PMID: 34469133 DOI: 10.1021/jacs.1c06464] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Organic radicals are open-shell species and have been extensively applied to functional materials due to their unique physicochemical properties with unpaired electrons; however, most of them are highly reactive and short-lived. Herein, a series of stable radicals were readily accessed in two steps from a bis(imino)acenaphthene-supported N-heterocyclic carbene (IPr(BIAN)) through enhancing the delocalization of spin density. The IPr(BIAN)-based radicals 3a-c, obtained by reduction of the corresponding iminium salts 2a-c with KC8, have been spectroscopically and crystallographically (3a,c) characterized. DFT calculations indicate that increasing the electron-withdrawing properties of the para substituent on the carbene carbon atom results in the spin density evolving from the acenaphthene ring to the phenyl ring. The IPr(BIAN)-based radicals 3a-c show excellent stability: they have half-lives of 1 week in well-aerated solutions and feature a high thermal decomposition temperature up to 200 °C.
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Affiliation(s)
- Jing Zhao
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, People's Republic of China
| | - Xin Li
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, People's Republic of China
| | - Ying-Feng Han
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710127, People's Republic of China
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18
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Kim Y, Byeon JE, Jeong GY, Kim SS, Song H, Lee E. Highly Stable 1,2-Dicarbonyl Radical Cations Derived from N-Heterocyclic Carbenes. J Am Chem Soc 2021; 143:8527-8532. [PMID: 33974426 DOI: 10.1021/jacs.1c00707] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stable organic radicals have been of great academic interest not only in the context of fundamental understanding of reactive intermediates but also because of their numerous applications as functional materials. Apart from the early examples of triphenylmethyl and TEMPO derivatives, reports on air- and water-stable organic radicals are scarce, and their development remains a challenge. Herein, we present the design and synthesis of a novel organic radical based on a 1,2-dicarbonyl scaffold supported by N-heterocyclic carbenes (NHCs). The presented radical cations exhibit remarkable stability toward various harsh conditions, such as the presence of reactive chemicals (reductants, oxidants, strong acids, and bases) or high temperatures, by far exceeding the stability of triphenylmethyl and TEMPO radicals. In addition, physiological conditions including aqueous buffer and blood serum are tolerated. The steric and electronic stabilization provided by the two NHC moieties enabled the successful design of the highly stable radical.
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Affiliation(s)
- Youngsuk Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Jung Eun Byeon
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Gu Yoon Jeong
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Seoung Su Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hayoung Song
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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19
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Muresan M, Subramanian H, Sibi MP, Green JR. Propargyl Radicals in Organic Synthesis. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100367] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Marcus Muresan
- Department of Chemistry and Biochemistry University of Windsor 401 Sunset Ave. Windsor Ontario N9B 3P4 Canada
| | - Hariharaputhiran Subramanian
- Department of Chemistry and Biochemistry North Dakota State University Dept 2735 PO Box 6050 Fargo North Dakota 58108-6050 USA
| | - Mukund P. Sibi
- Department of Chemistry and Biochemistry North Dakota State University Dept 2735 PO Box 6050 Fargo North Dakota 58108-6050 USA
| | - James R. Green
- Department of Chemistry and Biochemistry University of Windsor 401 Sunset Ave. Windsor Ontario N9B 3P4 Canada
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20
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Xu QD, Zhang LT, Zeng C, Yang YY, Su SD, Hu SM, Wu XT, Sheng TL. Influence of Fine Ligand Substitution Modification of the Isocyanidometal Bridge on Metal-to-Metal Charge Transfer Properties in Class II-III Mixed Valence Complexes. Chemistry 2021; 27:11183-11194. [PMID: 33939198 DOI: 10.1002/chem.202101194] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Indexed: 11/08/2022]
Abstract
The synthesis and characterization of Class II-III mixed valence complexes have been an interesting topic due to their special intermediate behaviour between localized and delocalized mixed valence complexes. To investigate the influence of the isocyanidometal bridge on metal-to-metal charge transfer (MMCT) properties, a family of new isocyanidometal-bridged complexes and their one-electron oxidation products cis-[Cp(dppe)Fe-CN-Ru(L)2 -NC-Fe(dppe)Cp][PF6 ]n (n=2, 3) (Cp=1,3-cyclopentadiene, dppe=1,2-bis(diphenylphosphino)ethane, L=2,2'-bipyridine (bpy, 1[PF6 ]n ), 5,5'-dimethyl-2,2'-bipyridyl (5,5'-dmbpy, 2[PF6 ]n ) and 4,4'-dimethyl-2,2'-bipyridyl (4,4'-dmbpy, 3[PF6 ]n )) have been synthesized and fully characterized. The experimental results suggest that all the one-electron oxidation products may belong to Class II-III mixed valence complexes, supported by TDDFT calculations. With the change of the substituents of the bipyridyl ligand on the Ru centre from H, 5,5'-dimethyl to 4,4'-dimethyl, the energy of MMCT for the one-electron oxidation complexes changes in the order: 13+ <23+ <33+ , and that for the two-electron oxidation complexes decreases in the order 14+ >34+ >24+ . The potential splitting (ΔE1/2 (2)) between the two terminal Fe centres for N[PF6 ]2 are the largest potential splitting for the cyanido-bridged complexes reported so far. This work shows that the smaller potential difference between the bridging and the terminal metal centres would result in the more delocalized mixed valence complex.
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Affiliation(s)
- Qing-Dou Xu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Lin-Tao Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China
| | - Chen Zeng
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Yu-Ying Yang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China
| | - Shao-Dong Su
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China
| | - Sheng-Min Hu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China
| | - Xin-Tao Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China
| | - Tian-Lu Sheng
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian, 350002, P.R. China
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21
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Schmid P, Fantuzzi F, Klopf J, Schröder NB, Dewhurst RD, Braunschweig H, Engel V, Engels B. Twisting versus Delocalization in CAAC- and NHC-Stabilized Boron-Based Biradicals: The Roles of Sterics and Electronics. Chemistry 2021; 27:5160-5170. [PMID: 33225473 PMCID: PMC8048672 DOI: 10.1002/chem.202004619] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/12/2020] [Indexed: 11/06/2022]
Abstract
Twisted boron-based biradicals featuring unsaturated C2 R2 (R=Et, Me) bridges and stabilization by cyclic (alkyl)(amino)carbenes (CAACs) were recently prepared. These species show remarkable geometrical and electronic differences with respect to their unbridged counterparts. Herein, a thorough computational investigation on the origin of their distinct electrostructural properties is performed. It is shown that steric effects are mostly responsible for the preference for twisted over planar structures. The ground-state multiplicity of the twisted structure is modulated by the σ framework of the bridge, and different R groups lead to distinct multiplicities. In line with the experimental data, a planar structure driven by delocalization effects is observed as global minimum for R=H. The synthetic elusiveness of C2 R2 -bridged systems featuring N-heterocyclic carbenes (NHCs) was also investigated. These results could contribute to the engineering of novel main group biradicals.
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Affiliation(s)
- Paul Schmid
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Felipe Fantuzzi
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Jonas Klopf
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Niklas B. Schröder
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Rian D. Dewhurst
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Volker Engel
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Bernd Engels
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
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22
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Krug M, Fröhlich N, Fehn D, Vogel A, Rominger F, Meyer K, Clark T, Kivala M, Guldi DM. Vorplanarisierte Triphenylamin‐basierte lineare gemischtvalente Ladungstransfersysteme. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Marcel Krug
- Department für Chemie und Pharmazie Interdisziplinäres Zentrum für Molekulare Materialien (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Deutschland
| | - Nina Fröhlich
- Department für Chemie und Pharmazie Lehrstuhl für Organische Chemie I Friedrich-Alexander-Universität Erlangen-Nürnberg Nikolaus-Fiebiger-Straße 10 91058 Erlangen Deutschland
| | - Dominik Fehn
- Department für Chemie und Pharmazie Anorganische Chemie Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Deutschland
| | - Alexander Vogel
- Institut für Organische Chemie Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
- Centre for Advanced Materials Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 225 69120 Heidelberg Deutschland
| | - Frank Rominger
- Institut für Organische Chemie Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Karsten Meyer
- Department für Chemie und Pharmazie Anorganische Chemie Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Deutschland
| | - Timothy Clark
- Department für Chemie and Pharmazie Computer-Chemie-Centrum Friedrich-Alexander-University Erlangen-Nürnberg Nägelsbachstraße 5 91052 Erlangen Deutschland
| | - Milan Kivala
- Institut für Organische Chemie Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
- Centre for Advanced Materials Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 225 69120 Heidelberg Deutschland
| | - Dirk M. Guldi
- Department für Chemie und Pharmazie Interdisziplinäres Zentrum für Molekulare Materialien (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Deutschland
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23
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Krug M, Fröhlich N, Fehn D, Vogel A, Rominger F, Meyer K, Clark T, Kivala M, Guldi DM. Pre-Planarized Triphenylamine-Based Linear Mixed-Valence Charge-Transfer Systems. Angew Chem Int Ed Engl 2021; 60:6771-6777. [PMID: 33306267 PMCID: PMC7986061 DOI: 10.1002/anie.202014567] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/04/2020] [Indexed: 11/08/2022]
Abstract
Three linear dimers with two redox-active planarized triphenylamines were synthesized and their structures verified by X-ray crystallography. Their radical cations, which exhibit electron self-exchange between the two redox centers, are of great interest. This process was thoroughly investigated by means of electron paramagnetic resonance spectroscopy, absorption spectroscopy, and (time-dependent) density functional theory calculations. A comparison of the key parameters of electron transfer with non-planarized nitrogen-centered building blocks emphasizes the impact of using redox centers with low internal reorganization energies. However, the distance-dependence attenuation factor of the super-exchange mechanisms remains similar.
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Affiliation(s)
- Marcel Krug
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058, Erlangen, Germany
| | - Nina Fröhlich
- Department of Chemistry and Pharmacy, Chair of Organic Chemistry I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Strasse 10, 91058, Erlangen, Germany
| | - Dominik Fehn
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Alexander Vogel
- Institute of Organic Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.,Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 225, 69120, Heidelberg, Germany
| | - Frank Rominger
- Institute of Organic Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany
| | - Timothy Clark
- Department of Chemistry and Pharmacy, Computer-Chemistry-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Naegelsbachstrasse 5, 91052, Erlangen, Germany
| | - Milan Kivala
- Institute of Organic Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.,Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 225, 69120, Heidelberg, Germany
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058, Erlangen, Germany
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24
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Abstract
Singlet fission (SF) is a photophysical downconversion pathway, in which a singlet excitation transforms into two triplet excited states. As such, it constitutes an exciton multiplication generation process, which is currently at the focal point for future integration into solar energy conversion devices. Beyond this, various other exciting applications were proposed, including quantum cryptography or organic light emitting diodes. Also, the mechanistic understanding evolved rapidly during the last year. Unfortunately, the number of suitable SF-chromophores is still limited. This is per se problematic, considering the wide range of envisaged applicability. With that in mind, we emphasize uncommon SF-scaffolds and outline requirements as well as strategies to expand the chromophore pool of SF-materials.
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Affiliation(s)
- Tobias Ullrich
- Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Department für Chemie und Pharmazie, Egerlandstr. 1-3, 91058 Erlangen, Germany.
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25
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Saalfrank C, Fantuzzi F, Kupfer T, Ritschel B, Hammond K, Krummenacher I, Bertermann R, Wirthensohn R, Finze M, Schmid P, Engel V, Engels B, Braunschweig H. cAAC-Stabilized 9,10-diboraanthracenes-Acenes with Open-Shell Singlet Biradical Ground States. Angew Chem Int Ed Engl 2020; 59:19338-19343. [PMID: 32662218 PMCID: PMC7589216 DOI: 10.1002/anie.202008206] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Indexed: 12/19/2022]
Abstract
Narrow HOMO-LUMO gaps and high charge-carrier mobilities make larger acenes potentially high-efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open-shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO-LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10-diboraanthracenes, which are shown to feature disjointed, open-shell singlet biradical ground states.
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Affiliation(s)
- Christian Saalfrank
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Felipe Fantuzzi
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Thomas Kupfer
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Benedikt Ritschel
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Kai Hammond
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Rüdiger Bertermann
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Raphael Wirthensohn
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Maik Finze
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Paul Schmid
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Volker Engel
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Bernd Engels
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Holger Braunschweig
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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26
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Saalfrank C, Fantuzzi F, Kupfer T, Ritschel B, Hammond K, Krummenacher I, Bertermann R, Wirthensohn R, Finze M, Schmid P, Engel V, Engels B, Braunschweig H. cAAC‐stabilisierte 9,10‐Diboraanthracene – offenschalige Singulettbiradikale. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008206] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Christian Saalfrank
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Thomas Kupfer
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Benedikt Ritschel
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Kai Hammond
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Ivo Krummenacher
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Rüdiger Bertermann
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Raphael Wirthensohn
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Maik Finze
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Paul Schmid
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Volker Engel
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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27
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Messelberger J, Grünwald A, Goodner SJ, Zeilinger F, Pinter P, Miehlich ME, Heinemann FW, Hansmann MM, Munz D. Aromaticity and sterics control whether a cationic olefin radical is resistant to disproportionation. Chem Sci 2020; 11:4138-4149. [PMID: 34760147 PMCID: PMC8562513 DOI: 10.1039/d0sc00699h] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/28/2020] [Indexed: 12/14/2022] Open
Abstract
We elucidate why some electron rich-olefins such as tetrathiafulvalene (TTF) or paraquat (1,1'-dimethyl-4,4'-bipyridinylidene) form persistent radical cations, whereas others such as the dimer of N,N'-dimethyl benzimidazolin-2-ylidene (benzNHC) do not. Specifically, three heterodimers derived from cyclic (alkyl) (amino) carbenes (CAAC) with N,N'-dimethyl imidazolin-2-ylidene (NHC), N,N'-dimethyl imidazolidin-2-ylidene (saNHC) and N-methyl benzothiazolin-2-ylidene (btNHC) are reported. Whereas the olefin radical cations with the NHC and btNHC are isolable, the NHC compound with a saturated backbone (saNHC) disproportionates instead to the biscation and olefin. Furthermore, the electrochemical properties of the electron-rich olefins derived from the dimerization of the saNHC and btNHC were assessed. Based on the experiments, we propose a general computational method to model the electrochemical potentials and disproportionation equilibrium. This method, which achieves an accuracy of 0.07 V (0.06 V with calibration) in reference to the experimental values, allows for the first time to rationalize and predict the (in)stability of olefin radical cations towards disproportionation. The combined results reveal that the stability of heterodimeric olefin radical cations towards disproportionation is mostly due to aromaticity. In contrast, homodimeric radical cations are in principle isolable, if lacking steric bulk in the 2,2' positions of the heterocyclic monomers. Rigid tethers increase accordingly the stability of homodimeric radical cations, whereas the electronic effects of substituents seem much less important for the disproportionation equilibrium.
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Affiliation(s)
- Julian Messelberger
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Annette Grünwald
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Stephen J Goodner
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Florian Zeilinger
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Piermaria Pinter
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Matthias E Miehlich
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Frank W Heinemann
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - Max M Hansmann
- Institut für Organische und Biomolekulare Chemie, Georg-August Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
- Organische Chemie, Technische Universität Dortmund Otto-Hahn-Str. 6 44227 Dortmund Germany
| | - Dominik Munz
- Lehrstuhl für Allgemeine und Anorganische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
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28
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Maiti A, Stubbe J, Neuman NI, Kalita P, Duari P, Schulzke C, Chandrasekhar V, Sarkar B, Jana A. CAAC‐Based Thiele and Schlenk Hydrocarbons. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Avijit Maiti
- Tata Institute of Fundamental Research (TIFR) Hyderabad Gopanpally Hyderabad-500107 Telangana India
| | - Jessica Stubbe
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität Berlin Fabeckstraße 34–36 14195 Berlin Germany
| | - Nicolás I. Neuman
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität Berlin Fabeckstraße 34–36 14195 Berlin Germany
- Instituto de Desarrollo Tecnológico para laIndustria Química, CCT Santa Fe CONICET-UNL Colectora Ruta Nacional 168, Km 472, Paraje El Pozo 3000 Santa Fe Argentina
| | - Pankaj Kalita
- Tata Institute of Fundamental Research (TIFR) Hyderabad Gopanpally Hyderabad-500107 Telangana India
| | - Prakash Duari
- Tata Institute of Fundamental Research (TIFR) Hyderabad Gopanpally Hyderabad-500107 Telangana India
| | - Carola Schulzke
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Germany
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research (TIFR) Hyderabad Gopanpally Hyderabad-500107 Telangana India
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
| | - Biprajit Sarkar
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität Berlin Fabeckstraße 34–36 14195 Berlin Germany
- Institut für Anorganische ChemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Anukul Jana
- Tata Institute of Fundamental Research (TIFR) Hyderabad Gopanpally Hyderabad-500107 Telangana India
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29
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Hu YX, Zhang J, Zhang F, Wang X, Yin J, Hartl F, Liu SH. Electronic Properties of Oxidized Cyclometalated Diiridium Complexes: Spin Delocalization Controlled by the Mutual Position of the Iridium Centers. Chemistry 2020; 26:4567-4575. [PMID: 31891433 DOI: 10.1002/chem.201904894] [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: 10/27/2019] [Revised: 12/20/2019] [Indexed: 11/10/2022]
Abstract
Four cyclometalated diiridium complexes, with IrCp*Cl (Cp*=η5 -C5 Me5 - ) termini bridged by 1,4- and 1,3-bis(p-tolyliminoethyl)benzene (1, 2), or 1,4- and 1,3-bis(2-pyridyl)benzene (3, 4), were prepared and characterized by nuclear magnetic resonance (NMR) spectroscopy and single-crystal X-ray diffraction (complexes 1, 2, and 4). The two iridium centers in complexes 1 and 3 are thus bound at the central benzene ring in the para-position (trans-Ir2), whereas those in complexes 2 and 4 are in the meta-position (cis-Ir2). Cyclic voltammograms of all four complexes show two consecutive one-electron oxidations. The potential difference between the two anodic steps in 1 and 3 is distinctly larger than that for 2 and 4. The visible-near-infrared (NIR)-short-wave infrared (SWIR) absorption spectra of trans-Ir2 monocations 1+ and 3+ are markedly different from those of cis-Ir2 monocations 2+ and 4+ . Notably, strong near-infrared electronic absorption appears only in the spectra of 1+ and 3+ whereas 2+ and 4+ absorb only weakly in the NIR-SWIR region. Combined DFT and TD-DFT calculations have revealed that (a) 1+ and 3+ (the diiridium-benzene trans-isomers) display the highest occupied spin-orbitals (HOSO) and the lowest unoccupied spin-orbital (LUSO) evenly delocalized over both molecule halves, and (b) their electronic absorptions in the NIR-SWIR region are attributed to mixed metal-to-ligand and ligand-to-ligand charge transfers (MLCT and LLCT). In contrast, cis-isomers 2+ and 4+ do not feature this stabilizing π-delocalization but a localized mixed-valence state showing a weak intervalence charge-transfer (IVCT) absorption in the SWIR region.
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Affiliation(s)
- Yu Xuan Hu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
| | - Jing Zhang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
| | - Fangfang Zhang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
| | - Xiaoyan Wang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
| | - Jun Yin
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
| | - František Hartl
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK
| | - Sheng Hua Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
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30
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Nayak MK, Stubbe J, Neuman NI, Narayanan RS, Maji S, Schulzke C, Chandrasekhar V, Sarkar B, Jana A. N,N'-Ethylene-Bridged Bis-2-Aryl-Pyrrolinium Cations to E-Diaminoalkenes: Non-Identical Stepwise Reversible Double-Redox Coupled Bond Activation Reactions. Chemistry 2020; 26:4425-4431. [PMID: 31994763 PMCID: PMC7187269 DOI: 10.1002/chem.202000255] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Indexed: 12/31/2022]
Abstract
This work presents a stepwise reversible two‐electron transfer induced hydrogen shift leading to the conversion of a bis‐pyrrolinium cation to an E‐diaminoalkene and vice versa. Remarkably, the forward and the reverse reaction, which are both reversible, follow two completely different reaction pathways. Establishing such unprecedented property in this type of processes was possible by developing a novel synthetic route towards the starting dication. All intermediates involved in both the forward and the backward reactions were comprehensively characterized by a combination of spectroscopic, crystallographic, electrochemical, spectroelectrochemical, and theoretical methods. The presented synthetic route opens up new possibilities for the generation of multi‐pyrrolinium cation scaffold‐based organic redox systems, which constitute decidedly sought‐after molecules in contemporary chemistry.
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Affiliation(s)
- Mithilesh Kumar Nayak
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500107, India
| | - Jessica Stubbe
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany
| | - Nicolás I Neuman
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany.,Instituto de Desarrollo Tecnológico para la Industria Química, CCT Santa Fe CONICET-UNL, Colectora Ruta Nacional 168, Km 472, Paraje El Pozo, 3000, Santa Fe, Argentina
| | | | - Sandipan Maji
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500107, India
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, 17487, Greifswald, Germany
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500107, India.,Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany.,Institut für Anorganische Chemie, Lehrstuhl für Anorganische Koordinationschemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500107, India
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31
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Maiti A, Stubbe J, Neuman NI, Kalita P, Duari P, Schulzke C, Chandrasekhar V, Sarkar B, Jana A. CAAC-Based Thiele and Schlenk Hydrocarbons. Angew Chem Int Ed Engl 2020; 59:6729-6734. [PMID: 31960562 PMCID: PMC7187164 DOI: 10.1002/anie.201915802] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Indexed: 01/17/2023]
Abstract
Diradicals have been of tremendous interest for over a century ever since the first reports of p- and m-phenylene-bridged diphenylmethylradicals in 1904 by Thiele and 1915 by Schlenk. Reported here are the first examples of cyclic(alkyl)(amino)carbene (CAAC) analogues of Thiele's hydrocarbon, a Kekulé diradical, and Schlenk's hydrocarbon, a non-Kekulé diradical, without using CAAC as a precursor. The CAAC analogue of Thiele's hydrocarbon has a singlet ground state, whereas the CAAC analogue of Schlenk's hydrocarbon contains two unpaired electrons. The latter forms a dimer, by an intermolecular double head-to-tail dimerization. This straightforward synthetic methodology is modular and can be extended for the generation of redox-active organic compounds.
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Affiliation(s)
- Avijit Maiti
- Tata Institute of Fundamental Research (TIFR) Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India
| | - Jessica Stubbe
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany
| | - Nicolás I Neuman
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany.,Instituto de Desarrollo Tecnológico para la, Industria Química, CCT Santa Fe CONICET-UNL, Colectora Ruta Nacional 168, Km 472, Paraje El Pozo, 3000, Santa Fe, Argentina
| | - Pankaj Kalita
- Tata Institute of Fundamental Research (TIFR) Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India
| | - Prakash Duari
- Tata Institute of Fundamental Research (TIFR) Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, 17487, Greifswald, Germany
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research (TIFR) Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.,Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany.,Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Anukul Jana
- Tata Institute of Fundamental Research (TIFR) Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India
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32
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Kundu G, De S, Tothadi S, Das A, Koley D, Sen SS. Saturated N-Heterocyclic Carbene Based Thiele's Hydrocarbon with a Tetrafluorophenylene Linker. Chemistry 2019; 25:16533-16537. [PMID: 31609519 DOI: 10.1002/chem.201904421] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/06/2019] [Indexed: 01/24/2023]
Abstract
The synthesis of a SIPr [1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene] derived Kekulé diradicaloid with a tetrafluorophenylene spacer (3) has been described. Two synthetic routes have been reported to access 3. The cleavage of C-F bond of C6 F6 by SIPr in the presence of BF3 led to double C-F activated compound with two tetrafluoro borate counter anions (2), which upon reduction by lithium metal afforded 3. Alternatively, 3 can be directly accessed in one step by reacting SIPr with C6 F6 in presence of Mg metal. Compounds 2 and 3 were well characterized spectroscopically and by single-crystal X-ray diffraction studies. Experimental and computational studies support the cumulenic closed-shell singlet state of 3 with a singlet-triplet energy gap (ΔES-T ) of 23.7 kcal mol-1 .
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Affiliation(s)
- Gargi Kundu
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), New Ghaziabad, 201002, India
| | - Sriman De
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, India
| | - Srinu Tothadi
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Abhishek Das
- Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata, 700032, India
| | - Debasis Koley
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), New Ghaziabad, 201002, India
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33
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Ou YAP, Hu Y, Xu M, Wang A, Liu SH. Rutheniumethynyl-triarylamine mixed-valence conjugated system: syntheses, (spectro-)electrochemistry, and theoretical calculations. J COORD CHEM 2019. [DOI: 10.1080/00958972.2019.1695125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- YA-Ping Ou
- Key Laboratory of Functional Metal-Organic Compounds of Hunan Province, Key Laboratory of Functional Organometallic Materials of Hunan Province College, College of Chemistry and Material Science, Hengyang Normal University, Hengyang, P.R. China
| | - Yuxuan Hu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, P.R. China
| | - Meng Xu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, P.R. China
| | - Aihui Wang
- Key Laboratory of Functional Metal-Organic Compounds of Hunan Province, Key Laboratory of Functional Organometallic Materials of Hunan Province College, College of Chemistry and Material Science, Hengyang Normal University, Hengyang, P.R. China
| | - Sheng Hua Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, P.R. China
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Werr M, Kaifer E, Wadepohl H, Himmel HJ. Tuneable Redox Chemistry and Electrochromism of Persistent Symmetric and Asymmetric Azine Radical Cations. Chemistry 2019; 25:12981-12990. [PMID: 31306523 DOI: 10.1002/chem.201902216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/21/2019] [Indexed: 12/16/2022]
Abstract
Molecular organic radicals have been intensively studied in the last decades, due to their interesting optical, magnetic and redox properties. Here we report the synthesis and characterisation of persistent organic radicals from one-electron oxidation of redox-active azines (RAAs), composed of two guanidinyl or related groups. By connecting two different groups together, asymmetric compounds result. In this way a series of compounds with varying redox potential is obtained that could be oxidised reversibly to the mono- and the dicationic charge states. The accessible redox states were fully determined by chemical redox reactions. The standard Gibbs free energy change for disproportionation of the radical monocation into the dication and the neutral molecule in solution, estimated from cyclovoltammetric measurements, varies between 43 and 71 kJ mol-1 . While the neutral RAAs absorb predominately UV light, the radical monocations display strong absorptions covering almost the entire visible region and extending for some compounds into the NIR region. A detailed analysis of this highly reversible electrochromism is presented, and the fast switching characteristics are demonstrated in an electrochromic test device.
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Affiliation(s)
- Marco Werr
- Anorganisch Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Anorganisch Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Anorganisch Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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35
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Arnold A, Sherbow TJ, Sayler RI, Britt RD, Thompson EJ, Muñoz MT, Fettinger JC, Berben LA. Organic Electron Delocalization Modulated by Ligand Charge States in [L 2M] n- Complexes of Group 13 Ions. J Am Chem Soc 2019; 141:15792-15803. [PMID: 31510741 DOI: 10.1021/jacs.9b05602] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Water-stable organic mixed valence (MV) compounds have been prepared by the reaction of reduced bis(imino)pyridine ligands (I2P) with the trichloride salts of Al, Ga, and In. The coordination of two tridentate ligands to each ion affords octahedral complexes that are accessible with five ligand charge states: [(I2P0)(I2P-)M]2+, [(I2P-)2M]+, (I2P-)(I2P2-)M, [(I2P2-)2M]-, and [(I2P2-)(I2P3-)M]2-, and for M = Al only, [(I2P3-)2M]3-. In solid-state structures, the anionic members of the redox series are stabilized by the intercalation of Na+ cations within the ligands. The MV members of the redox series, (I2P-)(I2P2-)M and [(I2P2-)(I2P3-)M]2-, show characteristic intervalence transitions, in the near-infrared regions between 6800-7400 and 7800-9000 cm-1, respectively. Cyclic voltammetry (CV), NIR spectroscopic, and X-ray structural studies support the assignment of class II for compounds [(I2P2-)(I2P3-)M]2- and class III for M = Al and Ga in (I2P-)(I2P2-)M. All compounds containing a singly reduced I2P- ligand exhibit a sharp, low-energy transition in the 5100-5600 cm-1 region that corresponds to a π*-π* transition. CV studies demonstrate that the electron-transfer events in each of the redox series, Al, Ga, and In, span 2.2, 1.4, and 1.2 V, respectively.
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Affiliation(s)
- Amela Arnold
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - Tobias J Sherbow
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - Richard I Sayler
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - R David Britt
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - Emily J Thompson
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - M Teresa Muñoz
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - James C Fettinger
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
| | - Louise A Berben
- Department of Chemistry , University of California-Davis , Davis , California 95616 , United States
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36
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Mayorga Burrezo P, Zeng W, Moos M, Holzapfel M, Canola S, Negri F, Rovira C, Veciana J, Phan H, Wu J, Lambert C, Casado J. Perylene π‐Bridges Equally Delocalize Anions and Cations: Proportioned Quinoidal and Aromatic Content. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201905657] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Paula Mayorga Burrezo
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra. 08193 Cerdanyola Spain
| | - Wangdong Zeng
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Michael Moos
- Institut für Organische Chemie & Center for Nanosystems Chemistry Julius Maximilians-Universität Würzburg 97074 Würzburg Germany
| | - Marco Holzapfel
- Institut für Organische Chemie & Center for Nanosystems Chemistry Julius Maximilians-Universität Würzburg 97074 Würzburg Germany
| | - Sofia Canola
- Dipartimento di Chimica “G. Ciamician” Università di Bologna Via F. Selmi 2 40126 Bologna Italy
| | - Fabrizia Negri
- Dipartimento di Chimica “G. Ciamician” Università di Bologna Via F. Selmi 2 40126 Bologna Italy
| | - Concepciò Rovira
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra. 08193 Cerdanyola Spain
| | - Jaume Veciana
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra. 08193 Cerdanyola Spain
| | - Hoa Phan
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Jishan Wu
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Christoph Lambert
- Institut für Organische Chemie & Center for Nanosystems Chemistry Julius Maximilians-Universität Würzburg 97074 Würzburg Germany
| | - Juan Casado
- Department of Physical Chemistry University of Malaga Campus de Teatinos s/n 229071 Malaga Spain
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Mayorga Burrezo P, Zeng W, Moos M, Holzapfel M, Canola S, Negri F, Rovira C, Veciana J, Phan H, Wu J, Lambert C, Casado J. Perylene π‐Bridges Equally Delocalize Anions and Cations: Proportioned Quinoidal and Aromatic Content. Angew Chem Int Ed Engl 2019; 58:14467-14471. [DOI: 10.1002/anie.201905657] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Paula Mayorga Burrezo
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra. 08193 Cerdanyola Spain
| | - Wangdong Zeng
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Michael Moos
- Institut für Organische Chemie & Center for Nanosystems Chemistry Julius Maximilians-Universität Würzburg 97074 Würzburg Germany
| | - Marco Holzapfel
- Institut für Organische Chemie & Center for Nanosystems Chemistry Julius Maximilians-Universität Würzburg 97074 Würzburg Germany
| | - Sofia Canola
- Dipartimento di Chimica “G. Ciamician” Università di Bologna Via F. Selmi 2 40126 Bologna Italy
| | - Fabrizia Negri
- Dipartimento di Chimica “G. Ciamician” Università di Bologna Via F. Selmi 2 40126 Bologna Italy
| | - Concepciò Rovira
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra. 08193 Cerdanyola Spain
| | - Jaume Veciana
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra. 08193 Cerdanyola Spain
| | - Hoa Phan
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Jishan Wu
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Christoph Lambert
- Institut für Organische Chemie & Center for Nanosystems Chemistry Julius Maximilians-Universität Würzburg 97074 Würzburg Germany
| | - Juan Casado
- Department of Physical Chemistry University of Malaga Campus de Teatinos s/n 229071 Malaga Spain
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Kim Y, Bielawski CW, Lee E. Oxygen atom transfer: a mild and efficient method for generating iminyl radicals. Chem Commun (Camb) 2019; 55:7061-7064. [PMID: 31143894 DOI: 10.1039/c9cc03521d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Treating iminoxyl species with oxygen acceptors such as PPh3 resulted in oxygen atom transfer and afforded the corresponding iminyl radicals. DFT and other calculations revealed that association between the oxygen atom acceptors and the iminoxyl species results in the formation of key intermediates during the reaction. Subsequent dissociation is accompanied with homolytic cleavage of the N-O bond and generates iminyl radicals with spin densities that are localized on exocyclic nitrogen atoms.
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Affiliation(s)
- Youngsuk Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea. and Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Christopher W Bielawski
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea and Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea and Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea. and Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea and Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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Nojo W, Ishigaki Y, Takeda T, Akutagawa T, Suzuki T. Selective Formation of a Mixed‐Valence State from Linearly Bridged Oligo(aromatic diamines): Drastic Structural Change into a Folded Columnar Stack for Half‐filled Polycations. Chemistry 2019; 25:7759-7765. [DOI: 10.1002/chem.201901272] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Indexed: 01/14/2023]
Affiliation(s)
- Wataru Nojo
- Department of ChemistryFaculty of ScienceHokkaido University Sapporo 060-0810 Japan
| | - Yusuke Ishigaki
- Department of ChemistryFaculty of ScienceHokkaido University Sapporo 060-0810 Japan
| | - Takashi Takeda
- Institute of Multidisciplinary Research for Advanced MaterialsTohoku University Sendai Miyagi 980-8577 Japan
| | - Tomoyuki Akutagawa
- Institute of Multidisciplinary Research for Advanced MaterialsTohoku University Sendai Miyagi 980-8577 Japan
| | - Takanori Suzuki
- Department of ChemistryFaculty of ScienceHokkaido University Sapporo 060-0810 Japan
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40
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Kundu S, Sinhababu S, Chandrasekhar V, Roesky HW. Stable cyclic (alkyl)(amino)carbene (cAAC) radicals with main group substituents. Chem Sci 2019; 10:4727-4741. [PMID: 31160949 PMCID: PMC6510188 DOI: 10.1039/c9sc01351b] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/06/2019] [Indexed: 11/21/2022] Open
Abstract
Recent attempts to isolate cyclic (alkyl)(amino)carbene stabilized radicals of p-block elements have been described here.
Isolation and characterization of stable radicals has been a long-pursued quest. While there has been some progress in this field particularly with respect to carbon, radicals involving heavier p-block elements are still considerably sparse. In this review we describe our recent successful efforts on the isolation of stable p-block element radicals particularly those involving aluminum, silicon, and phosphorus.
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Affiliation(s)
- Subrata Kundu
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany .
| | - Soumen Sinhababu
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany .
| | - Vadapalli Chandrasekhar
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany . .,Tata Institute of Fundamental Research Hyderabad , Hyderabad 500107 , India.,Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur 208016 , India .
| | - Herbert W Roesky
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany .
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41
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Mandal D, Sobottka S, Dolai R, Maiti A, Dhara D, Kalita P, Narayanan RS, Chandrasekhar V, Sarkar B, Jana A. Direct access to 2-aryl substituted pyrrolinium salts for carbon centre based radicals without pyrrolidine-2-ylidene alias cyclic(alkyl)(amino)carbene (CAAC) as a precursor. Chem Sci 2019; 10:4077-4081. [PMID: 31049189 PMCID: PMC6470959 DOI: 10.1039/c8sc05477k] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/27/2019] [Indexed: 12/20/2022] Open
Abstract
A new strategy to synthesise 2-substituted pyrrolinium salts.
The synthesis of organic radicals is challenging due to their inherent instability. In recent years, cyclic(alkyl)(amino)carbene (CAAC)-derived 2-substituted pyrrolinium salts have been used as synthons for the synthesis of isolable carbon-based radicals. Herein, we report a direct, easy and convenient method for the synthesis of 2-aryl substituted pyrrolinium salts without using CAAC as a precursor. These cations can be reduced to the corresponding radicals. The influence of the aryl substituent at the C-2 position on radical stabilization and dimerization has been investigated. Because of the large scope of our strategy (capability to modulate different substituents at all the C- and N-centres of the pyrrolinium salts), it has the merit to be an extremely effective and productive route for generating carbon-based radicals whose stability as well as reactivity can be varied.
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Affiliation(s)
- Debdeep Mandal
- Tata Institute of Fundamental Research Hyderabad , Gopanpally , Hyderabad-500107 , Telangana , India .
| | - Sebastian Sobottka
- Institut für Chemie und Biochemie, Anorganische Chemie , Freie Universität Berlin , Fabeckstraße 34-36 , 14195 , Berlin , Germany .
| | - Ramapada Dolai
- Tata Institute of Fundamental Research Hyderabad , Gopanpally , Hyderabad-500107 , Telangana , India .
| | - Avijit Maiti
- Tata Institute of Fundamental Research Hyderabad , Gopanpally , Hyderabad-500107 , Telangana , India .
| | - Debabrata Dhara
- Tata Institute of Fundamental Research Hyderabad , Gopanpally , Hyderabad-500107 , Telangana , India .
| | - Pankaj Kalita
- School of Chemical Sciences , National Institute of Science Education and Research , HBNI , Bhubaneswar-752050 , India
| | | | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad , Gopanpally , Hyderabad-500107 , Telangana , India . .,Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India .
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie, Anorganische Chemie , Freie Universität Berlin , Fabeckstraße 34-36 , 14195 , Berlin , Germany .
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad , Gopanpally , Hyderabad-500107 , Telangana , India .
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42
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Schiegerl LJ, Melaimi M, Tolentino DR, Klein W, Bertrand G, Fässler TF. Silylated Ge9 Clusters as New Ligands for Cyclic (Alkyl)amino and Mesoionic Carbene Copper Complexes. Inorg Chem 2019; 58:3256-3264. [DOI: 10.1021/acs.inorgchem.8b03338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lorenz J. Schiegerl
- Department of Chemistry, Technische Universität München (TUM), Lichtenbergstraße 4, 85748 Garching, Germany
| | - Mohand Melaimi
- UCSD−CNRS Joint Research Chemistry Laboratory (UMI 3555), University of California—San Diego, La Jolla, California 92093-0353, United States
| | - Daniel R. Tolentino
- UCSD−CNRS Joint Research Chemistry Laboratory (UMI 3555), University of California—San Diego, La Jolla, California 92093-0353, United States
| | - Wilhelm Klein
- Department of Chemistry, Technische Universität München (TUM), Lichtenbergstraße 4, 85748 Garching, Germany
| | - Guy Bertrand
- UCSD−CNRS Joint Research Chemistry Laboratory (UMI 3555), University of California—San Diego, La Jolla, California 92093-0353, United States
| | - Thomas F. Fässler
- Department of Chemistry, Technische Universität München (TUM), Lichtenbergstraße 4, 85748 Garching, Germany
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43
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Mondal T, Dutta S, De S, Thirumalai D, Koley D. Donor Stabilized Diatomic Gr.14 E 2 (E = C-Pb) Molecule D-E 2-D (D = NHC, aNHC, NNHC, NHSi, NHGe, cAAC, cAASi, cAAGe): A Theoretical Insight. J Phys Chem A 2019; 123:565-581. [PMID: 30562460 DOI: 10.1021/acs.jpca.8b11005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Quantum chemical calculations have been carried out to explore the detailed electronic structure and bonding scenario in various bis-donor stabilized E2 compounds (E = C-Pb). Our computational findings reveal that the thermodynamic stabilities of the E2 core gradually decrease as we move down the group. A linear D-E-E'-D framework is observed for C2 systems, while the heavier group 14 analogues possess trans-bent geometries. Consideration of few compounds as viable targets for synthesis is suggested by their corresponding calculated formation energies. In addition, the thermodynamic stabilities of C2 systems notably increase with the saturation of the donor ring framework and are even more pronounced for boron-substituted saturated NHD ligand. QTAIM calculations affirmed that the covalent nature of E-E' bonds shifts toward the donor-acceptor region as one traverses from top to bottom along group 14. The E-D and E'-D bonds in the C2 systems have covalent nature, whereas those in Si2-Pb2 systems are characterized by donor-acceptor bonds. In addition, we have computed proton affinities and vertical ionization potentials (VIPs) of these compounds. An excellent correlation was obtained between calculated VIPs and orbital energies of HOMOs. Furthermore, in the present study, we also explored the effect of bis-donors in the stabilization of heterodiatomic SiC compounds. Our calculations indicate that a typical bonding description of the SiC(D)2 compounds should be represented by a combination of a classical double bond between C-D with significant donor-acceptor interaction in Si-D, i.e., D → Si═C═D. The SiC(D)2 systems are found to be less stable than the corresponding dicarbon compounds C2(D)2, but they show significant stabilization compared to the corresponding disilicon systems Si2(D)2.
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Affiliation(s)
- Totan Mondal
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
| | - Sayan Dutta
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
| | - Sriman De
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
| | - D Thirumalai
- Department of Chemistry , Thiruvalluvar University , Serkkadu, Vellore 632 115 , India
| | - Debasis Koley
- Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741 246 , India
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44
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Deissenberger A, Welz E, Drescher R, Krummenacher I, Dewhurst RD, Engels B, Braunschweig H. A New Class of Neutral Boron‐Based Diradicals Spanned by a Two‐Carbon‐Atom Bridge. Angew Chem Int Ed Engl 2019; 58:1842-1846. [DOI: 10.1002/anie.201813335] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Andrea Deissenberger
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Eileen Welz
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Regina Drescher
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Ivo Krummenacher
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Rian D. Dewhurst
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Bernd Engels
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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45
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Deissenberger A, Welz E, Drescher R, Krummenacher I, Dewhurst RD, Engels B, Braunschweig H. Eine neue Strukturklasse neutraler borhaltiger Diradikale verbrückt über zwei Kohlenstoffatome. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201813335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Andrea Deissenberger
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Eileen Welz
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Regina Drescher
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Rian D. Dewhurst
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Bernd Engels
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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46
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Zhu C, Ji X, You D, Chen TL, Mu AU, Barker KP, Klivansky LM, Liu Y, Fang L. Extraordinary Redox Activities in Ladder-Type Conjugated Molecules Enabled by B ← N Coordination-Promoted Delocalization and Hyperconjugation. J Am Chem Soc 2018; 140:18173-18182. [PMID: 30507169 DOI: 10.1021/jacs.8b11337] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The introduction of B ← N coordinate bond-isoelectronic to C-C single bond-into π-systems represents a promising strategy to impart exotic redox and electrochromic properties into conjugated organic molecules and macromolecules. To achieve both reductive and oxidative activities using this strategy, a cruciform ladder-type molecular constitution was designed to accommodate oxidation-active, reduction-active, and B ← N coordination units into a compact structure. Two such compounds (BN-F and BN-Ph) were synthesized via highly efficient N-directed borylation. These molecules demonstrated well-separated, two reductive and two oxidative electron-transfer processes, corresponding to five distinct yet stable oxidation states, including a rarely observed boron-containing radical cation. Spectroelectrochemical measurements revealed unique optical characteristics for each of these reduced/oxidized species, demonstrating multicolor electrochromism with excellent recyclability. Distinct color changes were observed between each redox state with clear isosbestic points on the absorption spectra. The underlying redox mechanism was elucidated by a combination of computational and experimental investigations. Single-crystal X-ray diffraction analysis on the neutral state, the oxidized radical cation, and the reduced dianion of BN-Ph revealed structural transformations into two distinct quinonoid constitutions during the oxidation and reduction processes, respectively. B ← N coordination played an important role in rendering the robust and reversible multistage redox properties, by extending the charge and spin delocalization, by modulating the π-electron density, and by a newly established hyperconjugation mechanism.
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Affiliation(s)
| | | | | | - Teresa L Chen
- The Molecular Foundry , Lawrence Berkeley National Laboratory , One Cyclotron Road, Berkeley , California 94720 , United States
| | | | | | - Liana M Klivansky
- The Molecular Foundry , Lawrence Berkeley National Laboratory , One Cyclotron Road, Berkeley , California 94720 , United States
| | - Yi Liu
- The Molecular Foundry , Lawrence Berkeley National Laboratory , One Cyclotron Road, Berkeley , California 94720 , United States
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47
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Kim Y, Lee E. Stable Organic Radicals Derived from N‐Heterocyclic Carbenes. Chemistry 2018; 24:19110-19121. [PMID: 30058298 DOI: 10.1002/chem.201801560] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/23/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Youngsuk Kim
- Center for Self-assembly and ComplexityInstitute for Basic Science (IBS) Pohang 37673 Republic of Korea
- Department of ChemistryPohang University of Science and Technology Pohang 37673 Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and ComplexityInstitute for Basic Science (IBS) Pohang 37673 Republic of Korea
- Department of ChemistryPohang University of Science and Technology Pohang 37673 Republic of Korea
- Division of Advanced Materials SciencePohang University of Science and Technology Pohang 37673 Republic of Korea
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48
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Rottschäfer D, Busch J, Neumann B, Stammler HG, van Gastel M, Kishi R, Nakano M, Ghadwal RS. Diradical Character Enhancement by Spacing: N-Heterocyclic Carbene Analogues of Müller's Hydrocarbon. Chemistry 2018; 24:16537-16542. [DOI: 10.1002/chem.201804524] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Dennis Rottschäfer
- Anorganische Molekülchemie und Katalyse; Lehrstuhl für Anorganische Chemie und Strukturchemie; Centrum für Molekulare Materialien; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Jasmin Busch
- Anorganische Molekülchemie und Katalyse; Lehrstuhl für Anorganische Chemie und Strukturchemie; Centrum für Molekulare Materialien; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Beate Neumann
- Anorganische Molekülchemie und Katalyse; Lehrstuhl für Anorganische Chemie und Strukturchemie; Centrum für Molekulare Materialien; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Hans-Georg Stammler
- Anorganische Molekülchemie und Katalyse; Lehrstuhl für Anorganische Chemie und Strukturchemie; Centrum für Molekulare Materialien; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Maurice van Gastel
- Max-Planck-Institut für Kohlenforschung; Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Ryohei Kishi
- Department of Materials Engineering Science; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Masayoshi Nakano
- Department of Materials Engineering Science; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
- Institute for Molecular Science; 38 Nishigo-Naka Myodaiji, Okazaki 444-8585 Japan
| | - Rajendra S. Ghadwal
- Anorganische Molekülchemie und Katalyse; Lehrstuhl für Anorganische Chemie und Strukturchemie; Centrum für Molekulare Materialien; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
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49
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Welz E, Böhnke J, Dewhurst RD, Braunschweig H, Engels B. Unravelling the Dramatic Electrostructural Differences Between N-Heterocyclic Carbene- and Cyclic (Alkyl)(amino)carbene-Stabilized Low-Valent Main Group Species. J Am Chem Soc 2018; 140:12580-12591. [DOI: 10.1021/jacs.8b07644] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Eileen Welz
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Julian Böhnke
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Rian D. Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Bernd Engels
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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50
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Mandal D, Dolai R, Kalita P, Narayanan RS, Kumar R, Sobottka S, Sarkar B, Rajaraman G, Chandrasekhar V, Jana A. "Abnormal" Addition of NHC to a Conjugate Acid of CAAC: Formation of N-Alkyl-Substituted CAAC. Chemistry 2018; 24:12722-12727. [PMID: 29797625 DOI: 10.1002/chem.201802587] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 01/16/2023]
Abstract
The addition reactions of N-heterocyclic carbenes (NHCs) are mostly known to occur through the carbenic centre (C2), which leads to a "normal" adduct. Herein, we report the "abnormal" addition of NHCDip 1 (1,3-(2,6-iPr2 C6 H3 )-imidazole-2-ylidene) to a conjugate acid of cyclic (alkyl)(amino)carbene 2 (CAACiPr =1-iPr-3,3,5,5-Me4 -pyrrolinium triflate). Mechanistic study revealed that this reaction proceeded through the in situ formation of 1,3-(2,6-iPr2 C6 H3 )-imidazolium cation 4 and N-iPr-substituted CAAC 5 followed by the oxidative addition of compound 5 across the C4-H bond (alias backbone C-H) of compound 4. The in situ formation of compound 5 was also proven by the oxidative addition of it to the N-H group of iPrNH2 . DFT calculations also supported the mechanistic findings. A different methodology for the in situ generation of compound 5 by using TMPLi is also described.
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Affiliation(s)
- Debdeep Mandal
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-, 500107, Telangana, India
| | - Ramapada Dolai
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-, 500107, Telangana, India
| | - Pankaj Kalita
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar-, 752050, India
| | | | - Ravi Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-, 400076, India
| | - Sebastian Sobottka
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, 14195, Berlin, Germany
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-, 400076, India
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-, 500107, Telangana, India.,Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-, 208016, India
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-, 500107, Telangana, India
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