1
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Gogesch FS, Bauer L, Vollstädt FD, Linseis M, Senft L, Ivanović-Burmazović I, Winter RF. Pyrene fluorescence in 2,7-di(4-phenylethynyl)pyrene-bridged bis(alkenylruthenium) complexes. Dalton Trans 2023; 53:251-259. [PMID: 38037827 DOI: 10.1039/d3dt03114d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Complexes PyrDPE-RuCl and PyrDPE-Ruacac with a π-extended 2,7-di(4-phenylethynyl)pyrene linker undergo simultaneous one-electron oxidations of their {Ru}-styryl entities. The absence of an intervalence charge-transfer (IVCT) band at intermediate stages, where the mixed-valent, singly oxidized radical cation is present, and spin density confinement to the terminal styryl ruthenium site(s) are tokens of a lack of electronic coupling between the {Ru} entities across the π-conjugated linker. The close similarity of the linker-based π → π* bands in the complexes and the free ligand and their insensitivity towards oxidations at the terminal sites indicate that the central pyrenyl fluorophore is electronically decoupled from the electron-rich {Ru}-styryl termini. As a consequence, the complexes offer stable pyrene-based fluorescence emissions at 77 K, which are red-shifted from that of the linker.
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Affiliation(s)
- Franciska S Gogesch
- Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Lea Bauer
- Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Florian D Vollstädt
- Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Michael Linseis
- Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Laura Senft
- Fachbereich Chemie, Ludwig-Maximilian-Universität München, Butenandtstraße 5-13, Haus D, 81377 München, Germany
| | - Ivana Ivanović-Burmazović
- Fachbereich Chemie, Ludwig-Maximilian-Universität München, Butenandtstraße 5-13, Haus D, 81377 München, Germany
| | - Rainer F Winter
- Fachbereich Chemie, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
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2
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Pandit YA, Usman M, Sarkar A, Shah SJ, Rath SP. Control of spin coupling through a redox-active bridge in a dinickel(II) porphyrin dimer: step-wise oxidations enable isolations of a chlorin-porphyrin heterodimer and a dication diradical with a singlet ground state. Dalton Trans 2023; 52:877-891. [PMID: 36464989 DOI: 10.1039/d2dt03283j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A dinickel(II)porphyrin dimer has been used here in which the redox-active pyrrole-moiety, similar to the tryptophan residue in diheme enzymes such as MauG and bCcP, has been placed between two Ni(II)porphyrin centers connected via a flexible, but unconjugated methylene bridge. This arrangement provides a large physical separation between the two metal centers and thus displays almost no communication between them through the bridge. Upon treatment with DDQ as an oxidant, the dinickel(II) porphyrin dimer slowly gets converted into an indolizinium-fused chlorin-porphyrin heterodimer. However, oxidations of the dinickel(II) porphyrin dimer up to two oxidizing equivalents using oxidants such as AgSbF6 and FeCl3 resulted in the formation of a dication diradical complex. Interestingly, in order to stabilize such a highly oxidized dication diradical, two non-conjugated methylene spacers undergo facile 2e-/-2H+ oxidation to make the bridge fully π-conjugated for promoting through-bond communication. Through the oxidized and conjugated bridge, two porphyrin π-cation radicals display considerable communications leading to an efficient intramolecular spin coupling to form a singlet state. Interestingly, the redox-active nature of the bridge controls the electronic communication just by simple oxidation or reduction, and thereby, acts as a molecular switch for efficient magnetic relay.
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Affiliation(s)
- Younis Ahmad Pandit
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Anindya Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Syed Jehanger Shah
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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3
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Sanfui S, Usman M, Sarkar S, Pramanik S, Garribba E, Rath SP. Highly Oxidized Cobalt Porphyrin Dimer: Control of Spin Coupling via a Bridge. Inorg Chem 2022; 61:8419-8430. [PMID: 35613476 DOI: 10.1021/acs.inorgchem.1c03807] [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
A cobalt porphyrin dimer is constructed in which two Co(II)porphyrins are connected covalently through a redox-active diethylpyrrole moiety via a flexible but "nonconjugated" methylene bridge. Upon oxidation with even a mild oxidant such as iodine, each cobalt(II) center and porphyrin ring undergo 1e- oxidation, leading to the formation of a 4e--oxidized cobalt(III)porphyrin dication diradical complex. Other oxidants such as Cl2 and Br2 also produce similar results. To stabilize such highly oxidized dication diradicals, the "nonconjugated" methylene spacer undergoes a facile and spontaneous oxidation to form a methine group with a drastic structural change, thereby making the bridge fully π-conjugated and enabling through-bond communication. This results in a strong spin coupling between two π-cation radicals which stabilizes the singlet state. The experimental observations are also strongly supported by extensive density functional theory calculations. The present study highlights the crucial role played by the nature of the bridge in the long-range electronic communication.
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Affiliation(s)
- Sarnali Sanfui
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Sabyasachi Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Subhadip Pramanik
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Eugenio Garribba
- Dipartimento di Scienze Mediche, Chirurgiche e Sperimentali, Università di Sassari, Viale San Pietro, Sassari I-07100, Italy
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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4
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Pandit YA, Shah SJ, Usman M, Sarkar S, Garribba E, Rath SP. Long-Range Intramolecular Spin Coupling through a Redox-Active Bridge upon Stepwise Oxidations: Control and Effect of Metal Ions. Inorg Chem 2022; 61:5270-5282. [PMID: 35323011 DOI: 10.1021/acs.inorgchem.1c03945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dinickel(II) and dicopper(II) porphyrin dimers have been constructed in which two metalloporphyrin units are widely separated by a long unconjugated dipyrrole bridge. Two macrocycles are aligned somewhat orthogonally to each other, while oxidation of the bridge generates a fully π-conjugated butterfly-like structure, which, in turn, upon stepwise oxidations by stronger oxidants result in the formation of the corresponding one- and two-electron-oxidized species exhibiting unusual long-range charge/radical delocalization to produce intense absorptions in the near-infrared (NIR) region and electron paramagnetic resonance (EPR) signals of a triplet state due to interaction between the unpaired spins on the Cu(II) ions. Although the two metal centers have a large physical separation through the bridge (more than 16 Å), they share electrons efficiently between them, behaving as a single unit rather than two independent centers. Detailed UV-vis-NIR, electrospray ionization mass spectrometry, IR, variable-temperature magnetic study, and EPR spectroscopic investigations along with X-ray structure determination of unconjugated, conjugated, and one electron-oxidized complexes have been exploited to demonstrate the long-range electronic communication through the bridge. The experimental observations are also supported by density functional theory (DFT) and time-dependent DFT calculations. The present study highlights the crucial roles played by a redox-active bridge and metal in controlling the long-range electronic communication.
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Affiliation(s)
- Younis Ahmad Pandit
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Syed Jehanger Shah
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Sabyasachi Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Eugenio Garribba
- Dipartimento di Scienze Mediche, Chirurgiche e Sperimentali, Università di Sassari, Viale San Pietro, Sassari I-07100, Italy
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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5
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Kumar A, Usman M, Samanta D, Rath SP. Through Bridge Spin Coupling in Homo- and Heterobimetallic Porphyrin Dimers upon Stepwise Oxidations: A Spectroscopic and Theoretical Investigation. Chemistry 2021; 27:11428-11441. [PMID: 34061401 DOI: 10.1002/chem.202101384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Indexed: 12/16/2022]
Abstract
We have described copper(II)-iron(III) and copper(II)-manganese(III) heterobimetallic porphyrin dimers and compared them with the corresponding homobimetallic analogs. UV-visible spectra are very distinct in the heterometallic species while electrochemical studies demonstrate that these species, as compared to the homobimetallic analog, are much easier to oxidize. Combined Mössbauer, EPR, NMR, magnetic and UV-visible spectroscopic studies show that upon 2e-oxidation of the heterobimetallic complexes only ring-centered oxidation occurs. The energy differences between HOMO and LUMO are linearly dependent with the low-energy NIR band obtained for the 2e-oxidized complexes. Also, strong electronic communication between two porphyrin rings through the bridge facilitates coupling between various unpaired spins present while the coupling model depends on the nature of metal ions used. While unpaired spins of Fe(III) and the porphyrin π-cation radical are strongly antiferromagnetically coupled, such coupling is rather weak between Mn(III) and a porphyrin π-cation radical. Moreover, the coupling between two π-cation radicals are much stronger in the 2e-oxidized complexes of dimanganese(III) and copper(II)-manganese(III) porphyrin dimers as compared to their diiron(III) and copper(II)-iron(III) analogs. Furthermore, coupling between the unpaired spins of a π-cation radical and copper(II) is much stronger in the 2e-oxidized complex of copper(II)-iron(III) porphyrin dimer as compared to its copper(II)-manganese(III) analog. The Mulliken spin density distributions in 2e-oxidized homo- and heterobimetallic complexes show symmetric and asymmetric spread between the two macrocycles, respectively. In both the 2e-oxidized heterobimetallic complexes, the Cu(II) porphyrin center acts as a charge donor while Fe(III)/Mn(III) porphyrin center act as a charge acceptor. The experimental observations are also strongly supported by DFT calculations.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Deepannita Samanta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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6
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Kawashima H, Ukai S, Nozawa R, Fukui N, Fitzsimmons G, Kowalczyk T, Fliegl H, Shinokubo H. Determinant Factors of Three-Dimensional Aromaticity in Antiaromatic Cyclophanes. J Am Chem Soc 2021; 143:10676-10685. [PMID: 34170675 DOI: 10.1021/jacs.1c04348] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Three-dimensional aromaticity arising from the close stacking of two antiaromatic π-conjugated macrocycles has recently received considerable attention. Here, a cyclophane consisting of two antiaromatic Ni(II) norcorrole units tethered with two flexible alkyl chains was synthesized. The norcorrole cyclophane showed crystal polymorphism providing three different solid-state structures. Surprisingly, one of them adopted an aligned face-to-face stacking arrangement with negligible displacement along the slipping axis. Although the exchange repulsion between two π-clouds should be maximized in this orientation, the π-π distance is remarkably close (3.258 Å). Three-dimensional aromaticity in this conformation has been supported experimentally and theoretically as evidenced by small bond length alternations as well as the presence of a diatropic ring current. An analogous cyclophane with two aromatic Ni(II) porphyrin units was prepared for comparison. The porphyrin cyclophane exhibited a slipped-stacking conformation with a larger displacement (2.9 Å) and a larger interplanar distance (3.402 Å) without noticeable change of the aromaticity of each porphyrin unit. In solution, the norcorrole cyclophane forms a twist stacking arrangement with effective interplanar orbital overlap and exists in an equilibrium between stacked and nonstacked structures. Thermodynamic parameters of the stacking process were estimated, revealing an inherently large attractive interaction operating between two norcorrole units, which has been further supported by energy decomposition analysis.
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Affiliation(s)
- Hiroyuki Kawashima
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Shusaku Ukai
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Ryo Nozawa
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Norihito Fukui
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Garrett Fitzsimmons
- Department of Chemistry, Advanced Materials Science & Engineering Center and Institute for Energy Studies, Western Washington University, Bellingham, Washington 98229, United States
| | - Tim Kowalczyk
- Department of Chemistry, Advanced Materials Science & Engineering Center and Institute for Energy Studies, Western Washington University, Bellingham, Washington 98229, United States
| | - Heike Fliegl
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Hiroshi Shinokubo
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
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7
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Im EJ, Jung HW, Kang YK. Evaluation of
Through‐Space
Electronic Coupling in the Cofacially Aligned
π‐Stacked
Organic
Mixed‐Valence
System. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Eun Ji Im
- Department of Chemistry Sangmyung University Seoul 03016 South Korea
| | - Hae Won Jung
- Department of Chemistry Sangmyung University Seoul 03016 South Korea
| | - Youn K. Kang
- Department of Chemistry Sangmyung University Seoul 03016 South Korea
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8
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Kumar A, Sanfui S, Sciortino G, Maréchal J, Garribba E, Rath SP. Stepwise Oxidations in a Cofacial Copper(II) Porphyrin Dimer: Through‐Space Spin‐Coupling and Interplay between Metal and Radical Spins. Chemistry 2020; 26:7869-7880. [DOI: 10.1002/chem.202000348] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/06/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Amit Kumar
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
| | - Sarnali Sanfui
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
| | - Giuseppe Sciortino
- Dipartimento di Chimica e FarmaciaUniversità di Sassari Via Vienna 2 07100 Sassari Italy
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Cerdanyola del Vallés Barcelona Spain
| | - Jean‐Didier Maréchal
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Cerdanyola del Vallés Barcelona Spain
| | - Eugenio Garribba
- Dipartimento di Chimica e FarmaciaUniversità di Sassari Via Vienna 2 07100 Sassari Italy
| | - Sankar Prasad Rath
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
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9
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Jung HW, Yoon SE, Carroll PJ, Gau MR, Therien MJ, Kang YK. Distance Dependence of Electronic Coupling in Rigid, Cofacially Compressed, π-Stacked Organic Mixed-Valence Systems. J Phys Chem B 2020; 124:1033-1048. [DOI: 10.1021/acs.jpcb.9b09578] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hae Won Jung
- Department of Chemistry, Sangmyung University, Seoul 03016, Korea
| | - Sung Ewn Yoon
- Department of Chemistry, Sangmyung University, Seoul 03016, Korea
| | - Patrick J. Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Michael R. Gau
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Michael J. Therien
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Youn K. Kang
- Department of Chemistry, Sangmyung University, Seoul 03016, Korea
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10
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11
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Choi J, Ahn DS, Fujitsuka M, Tojo S, Ihee H, Majima T. Formation of the Charge-Localized Dimer Radical Cation of 2-Ethyl-9,10-dimethoxyanthracene in Solution Phase. Chemistry 2019; 25:5586-5594. [PMID: 30892780 DOI: 10.1002/chem.201900175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Indexed: 11/07/2022]
Abstract
Although dimer radical ions of aromatic molecules in the liquid-solution phase have been intensely studied, the understanding of charge-localized dimers, in which the extra charge is localized in a single monomer unit instead of being shared between two monomer units, is still elusive. In this study, the formation of a charge-localized dimer radical cation of 2-ethyl-9,10-dimethoxyanthracene (DMA), (DMA)2 .+ is investigated by transient absorption (TA) and time-resolved resonance Raman (TR3 ) spectroscopic methods combined with a pulse radiolysis technique. Visible- and near-IR TA signals in highly concentrated DMA solutions supported the formation of non-covalent (DMA)2 .+ by association of DMA and DMA.+ . TR3 spectra obtained from 30 ns to 300 μs time delays showed that the major bands are quite similar to those of DMA except for small transient bands, even at 30 ns time delay, suggesting that the positive charge of non-covalent (DMA)2 .+ is localized in a single monomer unit. From DFT calculations for (DMA)2 .+ , our TR3 spectra showed the best agreement with the calculated Raman spectrum of charge-localized edge-to-face T-shaped (DMA)2 .+ , termed DT.+ , although the charge-delocalized asymmetric π-stacked face-to-face (DMA)2 .+ , termed DF3.+ , is the most stable structure of (DMA)2 .+ according to the energetics from DFT calculations. The calculated potential energy curves for the association between DMA.+ and DMA showed that DT.+ is likely to be efficiently formed and contribute significantly to the TR3 spectra as a result of the permanent charge-induced Coulombic interactions and a dynamic equilibrium between charge localized and delocalized structures.
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Affiliation(s)
- Jungkweon Choi
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon, 305-701, Korea.,Department of Chemistry and KI of the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Korea
| | - Doo-Sik Ahn
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon, 305-701, Korea.,Department of Chemistry and KI of the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Korea
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
| | - Sachiko Tojo
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
| | - Hyotcherl Ihee
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon, 305-701, Korea.,Department of Chemistry and KI of the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Korea
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
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12
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Kumar A, Sil D, Usman M, Rath SP. A dimanganese(iii) porphyrin dication diradical and its transformation to a μ-hydroxo porphyrin–oxophlorin heterodimer. Chem Commun (Camb) 2019; 55:1588-1591. [DOI: 10.1039/c8cc09366k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin coupling models are different between iron and manganese in their dication diradical complexes, which is reflected in their reactivity as shown.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Debangsu Sil
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Mohammad Usman
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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13
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Kumar A, Banerjee S, Sarkar S, Rath SP. Stepwise oxidations of a nickel(ii)–iron(iii) heterobimetallic porphyrin dimer: structure, spectroscopic and theoretical investigation. Dalton Trans 2019; 48:10089-10103. [DOI: 10.1039/c9dt01776c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel nickel(ii)–iron(iii) heterobimetallic ethene-bridged porphyrin dimer has been synthesized which upon two-electron oxidation produces a nickel(ii)–iron(iii) dication diradical complex where radicals undergo extensive conjugation through the bridge for all possible interactions.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sayantani Banerjee
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sabyasachi Sarkar
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
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14
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Kröncke S, Herrmann C. Designing Long-Range Charge Delocalization from First-Principles. J Chem Theory Comput 2018; 15:165-177. [DOI: 10.1021/acs.jctc.8b00872] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Susanne Kröncke
- Department of Chemistry, University of Hamburg, Hamburg 20146, Germany
| | - Carmen Herrmann
- Department of Chemistry, University of Hamburg, Hamburg 20146, Germany
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15
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Liu Z, Frasconi M, Liu WG, Zhang Y, Dyar SM, Shen D, Sarjeant AA, Goddard WA, Wasielewski MR, Stoddart JF. Mixed-Valence Superstructure Assembled from a Mixed-Valence Host–Guest Complex. J Am Chem Soc 2018; 140:9387-9391. [DOI: 10.1021/jacs.8b05322] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Zhichang Liu
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Westlake University, 18 Shilongshan Road, Hangzhou 310024, China
| | - Marco Frasconi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova 35131, Italy
| | - Wei-Guang Liu
- Materials and Process Simulation Center (MC139-74), California Institute of Technology, Pasadena, California 91125, United States
| | | | | | | | | | - William A. Goddard
- Materials and Process Simulation Center (MC139-74), California Institute of Technology, Pasadena, California 91125, United States
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16
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Kinetics teach that electronic coupling lowers the free-energy change that accompanies electron transfer. Proc Natl Acad Sci U S A 2018; 115:7248-7253. [PMID: 29941573 DOI: 10.1073/pnas.1722401115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electron-transfer theories predict that an increase in the quantum-mechanical mixing (HDA) of electron donor and acceptor wavefunctions at the instant of electron transfer drives equilibrium constants toward unity. Kinetic and equilibrium studies of four acceptor-bridge-donor (A-B-D) compounds reported herein provide experimental validation of this prediction. The compounds have two redox-active groups that differ only by the orientation of the aromatic bridge: a phenyl-thiophene bridge (p) that supports strong electronic coupling of HDA > 1,000 cm-1; and a xylyl-thiophene bridge (x) that prevents planarization and decreases HDA < 100 cm-1 without a significant change in distance. Pulsed-light excitation allowed kinetic determination of the equilibrium constant, Keq In agreement with theory, Keq(p) were closer to unity compared to Keq(x). A van't Hoff analysis provided clear evidence of an adiabatic electron-transfer pathway for p-series and a nonadiabatic pathway for x-series. Collectively, the data show that the absolute magnitude of the thermodynamic driving force for electron transfers are decreased when adiabatic pathways are operative, a finding that should be taken into account in the design of hybrid materials for solar energy conversion.
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17
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Shafizadeh N, Boyé-Péronne S, Soorkia S, Cunha de Miranda BK, Garcia GA, Nahon L, Chen S, de la Lande A, Poisson L, Soep B. The surprisingly high ligation energy of CO to ruthenium porphyrins. Phys Chem Chem Phys 2018; 20:11730-11739. [PMID: 29687125 DOI: 10.1039/c8cp01190g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combined theoretical and experimental approach has been used to investigate the binding energy of a ruthenium metalloporphyrin ligated with CO, ruthenium tetraphenylporphyrin [RuII TPP], in the RuII oxidation degree. Measurements performed with VUV ionization using the DESIRS beamline at Synchrotron SOLEIL led to adiabatic ionization energies of [RuII TPP] and its complex with CO, [RuII TPP-CO], of 6.48 ± 0.03 eV and 6.60 ± 0.03 eV, respectively, while the ion dissociation threshold of [RuII TPP-CO]+ is measured to be 8.36 ± 0.03 eV using the ground-state neutral complex. These experimental data are used to derive the binding energies of the CO ligand in neutral and cationic complexes (1.88 ± 0.06 eV and 1.76 ± 0.06 eV, respectively) using a Born-Haber cycle. Density functional theory calculations, in very satisfactory agreement with the experimental results, help to get insights into the metal-ligand bond. Notably, the high ligation energies can be rationalized in terms of the ruthenium orbital structure, which is singular compared to that of the iron atom. Thus, beyond indications of a strengthening of the Ru-CO bond due to the decrease in the CO vibrational frequency in the complex as compared to the Fe-CO bond, high-level calculations are essential to accurately describe the metal ligand (CO) bond and show that the Ru-CO bond energy is strongly affected by the splitting of triplet and singlet spin states in uncomplexed [Ru TPP].
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Affiliation(s)
- Niloufar Shafizadeh
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, Université Paris-Sud, Orsay F-91405, France.
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Keshri SK, Asthana D, Chorol S, Kumar Y, Mukhopadhyay P. Appending Diverse π-Extended Acceptors with Tetrathiafulvalene/Dithiafulvalene Donors: Multistate Redox Properties, Radical Ion Generation, and Mid-IR-Absorbing Mixed-Valence States. Chemistry 2018; 24:1821-1832. [DOI: 10.1002/chem.201704604] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Sudhir Kumar Keshri
- Supramolecular and Material Chemistry Lab, School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110 067 India
| | - Deepak Asthana
- Supramolecular and Material Chemistry Lab, School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110 067 India
| | - Sonam Chorol
- Supramolecular and Material Chemistry Lab, School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110 067 India
| | - Yogendra Kumar
- Supramolecular and Material Chemistry Lab, School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110 067 India
| | - Pritam Mukhopadhyay
- Supramolecular and Material Chemistry Lab, School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110 067 India
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19
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Guchhait T, Sarkar S, Pandit YA, Rath SP. Probing Bis‐FeIVMauG: Isolation of Highly Reactive Radical Intermediates. Chemistry 2017; 23:10270-10275. [DOI: 10.1002/chem.201702321] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Tapas Guchhait
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
| | - Sabyasachi Sarkar
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
| | - Younis Ahmad Pandit
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
| | - Sankar Prasad Rath
- Department of ChemistryIndian Institute of Technology Kanpur Kanpur 208016 India
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20
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Burrezo PM, Lin NT, Nakabayashi K, Ohkoshi SI, Calzado EM, Boj PG, Díaz García MA, Franco C, Rovira C, Veciana J, Moos M, Lambert C, López Navarrete JT, Tsuji H, Nakamura E, Casado J. Bis(aminoaryl) Carbon-Bridged Oligo(phenylenevinylene)s Expand the Limits of Electronic Couplings. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201610921] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Nai-Ti Lin
- Department of Chemistry; School of Science; The University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Koji Nakabayashi
- Department of Chemistry; School of Science; The University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Shin-ichi Ohkoshi
- Department of Chemistry; School of Science; The University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Eva M. Calzado
- Dpto. Física, Ingeniería de Sistemas y Teoría de la Señal; Dpto. Óptica and Dpto de Física Aplicada and Instituto Universitario de Materiales de Alicante; Universidad de Alicante; Alicante 03080 Spain
| | - Pedro G. Boj
- Dpto. Física, Ingeniería de Sistemas y Teoría de la Señal; Dpto. Óptica and Dpto de Física Aplicada and Instituto Universitario de Materiales de Alicante; Universidad de Alicante; Alicante 03080 Spain
| | - María A. Díaz García
- Dpto. Física, Ingeniería de Sistemas y Teoría de la Señal; Dpto. Óptica and Dpto de Física Aplicada and Instituto Universitario de Materiales de Alicante; Universidad de Alicante; Alicante 03080 Spain
| | - Carlos Franco
- Department of Molecular Nanoscience and Organic Materials; Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Campus de la UAB Bellaterra 08193 Spain
| | - Concepciò Rovira
- Department of Molecular Nanoscience and Organic Materials; Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Campus de la UAB Bellaterra 08193 Spain
| | - Jaume Veciana
- Department of Molecular Nanoscience and Organic Materials; Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Campus de la UAB Bellaterra 08193 Spain
| | - Michael Moos
- Institut für Organische Chemie; Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Christoph Lambert
- Institut für Organische Chemie; Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | | | - Hayato Tsuji
- Department of Chemistry; School of Science; The University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
- Present address: Department of Chemistry; Faculty of Science; Kanagawa University; Kanagawa 259-1293 Japan
| | - Eiichi Nakamura
- Department of Chemistry; School of Science; The University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Juan Casado
- Department of Physical Chemistry; University of Málaga; 29071 Málaga Spain
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Burrezo PM, Lin NT, Nakabayashi K, Ohkoshi SI, Calzado EM, Boj PG, Díaz García MA, Franco C, Rovira C, Veciana J, Moos M, Lambert C, López Navarrete JT, Tsuji H, Nakamura E, Casado J. Bis(aminoaryl) Carbon-Bridged Oligo(phenylenevinylene)s Expand the Limits of Electronic Couplings. Angew Chem Int Ed Engl 2017; 56:2898-2902. [PMID: 28140501 DOI: 10.1002/anie.201610921] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Indexed: 11/10/2022]
Abstract
Carbon-bridged bis(aminoaryl) oligo(para-phenylenevinylene)s have been prepared and their optical, electrochemical, and structural properties analyzed. Their radical cations are class III and class II mixed-valence systems, depending on the molecular size, and they show electronic couplings which are among the largest for the self-exchange reaction of purely organic molecules. In their dication states, the antiferromagnetic coupling is progressively tuned with size from quinoidal closed-shell to open-shell biradicals. The data prove that the electronic coupling in the radical cations and the singlet-triplet gap in the dications show similar small attenuation factors, thus allowing charge/spin transfer over rather large distances.
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Affiliation(s)
| | - Nai-Ti Lin
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Koji Nakabayashi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shin-Ichi Ohkoshi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Eva M Calzado
- Dpto. Física, Ingeniería de Sistemas y Teoría de la Señal, Dpto. Óptica and Dpto de Física Aplicada and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Alicante, 03080, Spain
| | - Pedro G Boj
- Dpto. Física, Ingeniería de Sistemas y Teoría de la Señal, Dpto. Óptica and Dpto de Física Aplicada and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Alicante, 03080, Spain
| | - María A Díaz García
- Dpto. Física, Ingeniería de Sistemas y Teoría de la Señal, Dpto. Óptica and Dpto de Física Aplicada and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Alicante, 03080, Spain
| | - Carlos Franco
- Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Concepciò Rovira
- Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Jaume Veciana
- Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, Bellaterra, 08193, Spain
| | - Michael Moos
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Christoph Lambert
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | | | - Hayato Tsuji
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Present address: Department of Chemistry, Faculty of Science, Kanagawa University, Kanagawa, 259-1293, Japan
| | - Eiichi Nakamura
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Juan Casado
- Department of Physical Chemistry, University of Málaga, 29071, Málaga, Spain
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22
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Zhang J, Guo SZ, Dong YB, Rao L, Yin J, Yu GA, Hartl F, Liu SH. Multistep Oxidation of Diethynyl Oligophenylamine-Bridged Diruthenium and Diiron Complexes. Inorg Chem 2017; 56:1001-1015. [PMID: 28045545 DOI: 10.1021/acs.inorgchem.6b02809] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Homo-dinuclear nonlinear complexes [{M(dppe)Cp*}2{μ-(-C≡C)2X}] (dppe = 1,2-bis(diphenylphosphino)ethane; Cp* = η5-C5Me5; X = triphenylamine (TPA), M = Ru (1a) and Fe (1b); X = N,N,N',N'-tetraphenylphenylene-1,4-diamine (TPPD), M = Ru (2a)) were prepared and characterized by 1H, 13C, and 31P NMR spectroscopy and single-crystal X-ray diffraction (1a, 2a). Attempts to prepare the diiron analogue of 2a were not successful. Experimental data obtained from cyclic voltammetry, square wave voltammetry, UV-vis-NIR (NIR = near-infrared) spectro-electrochemistry, and very informative IR spectro-electrochemistry in the C≡C stretching region, combined with density functional theory calculations, afford to make an emphasizing assessment of the close association between the metal-ethynyl termini and the oligophenylamine bridge core as well as their respective involvement in sequential one-electron oxidations of these complexes. The anodic behavior of the homo-bimetallic complexes depends strongly both on the metal center and the length of the oligophenylamine bridge core. The poorly separated first two oxidations of diiron complex 1b are localized on the electronically nearly independent Fe termini. In contrast, diruthenium complex 1a exhibits a significantly delocalized character and a marked electronic communication between the ruthenium centers through the diethynyl-TPA bridge. The ruthenium-ethynyl halves in 2a, separated by the doubly extended and more flexible TPPD bridge core, show a lower degree of electronic coupling, resulting in close-lying first two anodic waves and the NIR electronic absorption of [2a]+ with an indistinctive intervalence charge transfer character. Finally, the third anodic waves in the voltammetric responses of the homo-bimetallic complexes are associated with the concurrent exclusive oxidation of the TPA or TPPD bridge cores.
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Affiliation(s)
- Jing Zhang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University , Wuhan 430079, P. R. China
| | - Shen-Zhen Guo
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University , Wuhan 430079, P. R. China
| | - Yu-Bao Dong
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University , Wuhan 430079, P. R. China
| | - Li Rao
- 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
| | - Guang-Ao Yu
- 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, U.K
| | - 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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23
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Filipczyk G, Lehrich SW, Hildebrandt A, Rüffer T, Schaarschmidt D, Korb M, Lang H. Multiferrocenyl Cobalt‐Based Sandwich Compounds. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600848] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Grzegorz Filipczyk
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
| | - Steve W. Lehrich
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
| | - Alexander Hildebrandt
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
| | - Tobias Rüffer
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
| | - Dieter Schaarschmidt
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
| | - Marcus Korb
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
| | - Heinrich Lang
- Technische Universität Chemnitz Fakultät für Naturwissenschaften Institut für Chemie Anorganische Chemie 09107 Chemnitz Germany
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24
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Mangaud E, de la Lande A, Meier C, Desouter-Lecomte M. Electron transfer within a reaction path model calibrated by constrained DFT calculations: application to mixed-valence organic compounds. Phys Chem Chem Phys 2015; 17:30889-903. [PMID: 26041466 DOI: 10.1039/c5cp01194a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The quantum dynamics of electron transfer in mixed-valence organic compounds is investigated using a reaction path model calibrated by constrained density functional theory (cDFT). Constrained DFT is used to define diabatic states relevant for describing the electron transfer, to obtain equilibrium structures for each of these states and to estimate the electronic coupling between them. The harmonic analysis at the diabatic minima yields normal modes forming the dissipative bath coupled to the electronic states. In order to decrease the system-bath coupling, an effective one dimensional vibronic Hamiltonian is constructed by partitioning the modes into a linear reaction path which connects both equilibrium positions and a set of secondary vibrational modes, coupled to this reaction coordinate. Using this vibronic model Hamiltonian, dissipative quantum dynamics is carried out using Redfield theory, based on a spectral density which is determined from the cDFT results. In a first benchmark case, the model is applied to a series of mixed-valence organic compounds formed by two 1,4-dimethoxy-3-methylphenylene fragments linked by an increasing number of phenylene bridges. This allows us to examine the coherent electron transfer in extreme situations leading to a ground adiabatic state with or without a barrier and therefore to the trapping of the charge or to an easy delocalization.
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Affiliation(s)
- E Mangaud
- Laboratoire Collisions Agrégats Réactivité, UMR 5589, IRSAMC, Université Toulouse III Paul Sabatier, Bât. 3R1b4, 118 route de Narbonne, F-31062, Toulouse, France. and Laboratoire de Chimie Physique, UMR 8000, Université Paris-Sud, Bât. 349, 15 avenue Jean Perrin, F-91405 Orsay, France
| | - A de la Lande
- Laboratoire de Chimie Physique, UMR 8000, Université Paris-Sud, Bât. 349, 15 avenue Jean Perrin, F-91405 Orsay, France
| | - C Meier
- Laboratoire Collisions Agrégats Réactivité, UMR 5589, IRSAMC, Université Toulouse III Paul Sabatier, Bât. 3R1b4, 118 route de Narbonne, F-31062, Toulouse, France.
| | - M Desouter-Lecomte
- Laboratoire de Chimie Physique, UMR 8000, Université Paris-Sud, Bât. 349, 15 avenue Jean Perrin, F-91405 Orsay, France and Département de Chimie, Université de Liège, Sart Tilman, B6, B-4000 Liège, Belgium
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25
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Dey S, Sil D, Rath SP. A Highly Oxidized Cobalt Porphyrin Dimer: Spin Coupling and Stabilization of the Four-Electron Oxidation Product. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201509430] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Soumyajit Dey
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | - Debangsu Sil
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | - Sankar Prasad Rath
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
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26
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Dey S, Sil D, Rath SP. A Highly Oxidized Cobalt Porphyrin Dimer: Spin Coupling and Stabilization of the Four-Electron Oxidation Product. Angew Chem Int Ed Engl 2015; 55:996-1000. [DOI: 10.1002/anie.201509430] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Soumyajit Dey
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | - Debangsu Sil
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | - Sankar Prasad Rath
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
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27
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Sil D, Dey S, Kumar A, Bhowmik S, Rath SP. Oxidation triggers extensive conjugation and unusual stabilization of two di-heme dication diradical intermediates: role of bridging group for electronic communication. Chem Sci 2015; 7:1212-1223. [PMID: 29910877 PMCID: PMC5975787 DOI: 10.1039/c5sc03120f] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/26/2015] [Indexed: 11/21/2022] Open
Abstract
Synthetic analogs of diheme enzyme MauG have been reported. Unlike the bis-Fe(iv) state in MauG, the 2e-oxidation stabilizes two ferric hemes, each coupled with a porphyrin π-cation radical.
MauG is a diheme enzyme that utilizes two covalently bound c-type hemes to catalyse the biosynthesis of the protein-derived cofactor tryptophan tryptophylquinone. The two hemes are physically separated by 14.5 Å and a hole-hopping mechanism is proposed in which a tryptophan residue located between the hemes undergoes reversible oxidation and reduction to increase the effective electronic coupling element and enhance the rate of reversible electron transfer between the hemes in bis-Fe(iv) MauG. The present work describes the structure and spectroscopic investigation of 2e-oxidations of the synthetic diheme analogs in which two heme centers are covalently connected through a conjugated ethylene bridge that leads to the stabilization of two unusual trans conformations (U and P′ forms) with different and distinct spectroscopic and geometric features. Unlike in MauG, where the two oxidizing equivalents are distributed within the diheme system giving rise to the bis-Fe(iv) redox state, the synthetic analog stabilizes two ferric hemes, each coupled with a porphyrin cation radical, a scenario resembling the binuclear dication diradical complex. Interestingly, charge resonance-transition phenomena are observed here both in 1e and 2e-oxidised species from the same system, which are also clearly distinguishable by their relative position and intensity. Detailed UV-vis-NIR, X-ray, Mössbauer, EPR and 1H NMR spectroscopic investigations as well as variable temperature magnetic studies have unraveled strong electronic communications between two porphyrin π-cation radicals through the bridging ethylene group. The extensive π-conjugation also allows antiferromagnetic coupling between iron(iii) centers and porphyrin radical spins of both rings. DFT calculations revealed extended π-conjugation and H-bonding interaction as the major factors in controlling the stability of the conformers.
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Affiliation(s)
- Debangsu Sil
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Soumyajit Dey
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Amit Kumar
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Susovan Bhowmik
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Sankar Prasad Rath
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
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Mani T, Grills DC, Newton MD, Miller JR. Electron Localization of Anions Probed by Nitrile Vibrations. J Am Chem Soc 2015; 137:10979-91. [DOI: 10.1021/jacs.5b04648] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomoyasu Mani
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - David C. Grills
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Marshall D. Newton
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - John R. Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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29
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Kong DD, Xue LS, Jang R, Liu B, Meng XG, Jin S, Ou YP, Hao X, Liu SH. Conformational Tuning of the Intramolecular Electronic Coupling in Molecular-Wire Biruthenium Complexes Bridged by Biphenyl Derivatives. Chemistry 2015; 21:9895-904. [PMID: 26013288 DOI: 10.1002/chem.201500509] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Dan-Dan Kong
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Lu-Sha Xue
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Rui Jang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Bin Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Xiang-Gao Meng
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Shan Jin
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China).
| | - Ya-Ping Ou
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Xiao Hao
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China)
| | - Sheng-Hua Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079 (P. R. China).
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Geng J, Davis I, Liu A. Probing bis-Fe(IV) MauG: experimental evidence for the long-range charge-resonance model. Angew Chem Int Ed Engl 2015; 54:3692-6. [PMID: 25631460 PMCID: PMC4363735 DOI: 10.1002/anie.201410247] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/14/2014] [Indexed: 11/08/2022]
Abstract
The biosynthesis of tryptophan tryptophylquinone, a protein-derived cofactor, involves a long-range reaction mediated by a bis-Fe(IV) intermediate of a diheme enzyme, MauG. Recently, a unique charge-resonance (CR) phenomenon was discovered in this intermediate, and a biological, long-distance CR model was proposed. This model suggests that the chemical nature of the bis-Fe(IV) species is not as simple as it appears; rather, it is composed of a collection of resonance structures in a dynamic equilibrium. Here, we experimentally evaluated the proposed CR model by introducing small molecules to, and measuring the temperature dependence of, bis-Fe(IV) MauG. Spectroscopic evidence was presented to demonstrate that the selected compounds increase the decay rate of the bis-Fe(IV) species by disrupting the equilibrium of the resonance structures that constitutes the proposed CR model. The results support this new CR model and bring a fresh concept to the classical CR theory.
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Affiliation(s)
- Jiafeng Geng
- Department of Chemistry and Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, Georgia, United States, Homepage: http://Feradical.gsu.edu
| | - Ian Davis
- Department of Chemistry and Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, Georgia, United States, Homepage: http://Feradical.gsu.edu
| | - Aimin Liu
- Department of Chemistry and Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, Georgia, United States, Homepage: http://Feradical.gsu.edu
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Geng J, Davis I, Liu A. Probing Bis-FeIVMauG: Experimental Evidence for the Long-Range Charge-Resonance Model. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410247] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Winter RF. Half-Wave Potential Splittings ΔE1/2 as a Measure of Electronic Coupling in Mixed-Valent Systems: Triumphs and Defeats. Organometallics 2014. [DOI: 10.1021/om500029x] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Rainer F. Winter
- Fachbereich
Chemie, Universität Konstanz, Universitätsstraße 10, D-78457 Konstanz, Germany
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Bis-Fe(IV): nature's sniper for long-range oxidation. J Biol Inorg Chem 2014; 19:1057-67. [PMID: 24722994 DOI: 10.1007/s00775-014-1123-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
Iron-dependent enzymes are prevalent in nature and participate in a wide range of biological redox activities. Frequently, high-valence iron intermediates are involved in the catalytic events of iron-dependent enzymes, especially when the activation of peroxide or molecular oxygen is involved. Building on the fundamental framework of iron-oxygen chemistry, these reactive intermediates constantly attract significant attention from the enzymology community. During the past few decades, tremendous efforts from a number of laboratories have been dedicated to the capture and characterization of these intermediates to improve mechanistic understandings. In 2008, an unprecedented bis-Fe(IV) intermediate was reported in a c-type diheme enzyme, MauG, which is involved in the maturation of a tryptophan tryptophylquinone cofactor of methylamine dehydrogenase. This intermediate, although chemically equivalent to well-characterized high-valence iron intermediates, such as compound I, compound ES, and intermediate Q in methane monooxygenase, as well as the hypothetical Fe(V) species in Rieske non-heme oxygenases, is orders of magnitude more stable than these other high-valence species in the absence of its primary substrate. It has recently been discovered that the bis-Fe(IV) intermediate exhibits a unique near-IR absorption feature which has been attributed to a novel charge-resonance phenomenon. This review compares the properties of MauG with structurally related enzymes, summarizes the current knowledge of this new high-valence iron intermediate, including its chemical origin and structural basis, explores the formation and consequences of charge resonance, and recounts the long-range catalytic mechanism in which bis-Fe(IV) participates. Biological strategies for storing oxidizing equivalents with iron ions are also discussed.
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Muratsugu S, Kishida M, Sakamoto R, Nishihara H. Comparative Study of Photochromic Ferrocene‐Conjugated Dimethyldihydropyrene Derivatives. Chemistry 2013; 19:17314-27. [DOI: 10.1002/chem.201303456] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Satoshi Muratsugu
- Department of Chemistry, School of Science, The University of Tokyo, 7‐3‐1, Hongo, Bunkyo‐Ku, Tokyo 113‐0033 (Japan), Fax: (+81) 3‐5841‐8063
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo‐cho, Chikusa‐Ku, Nagoya 464‐8602 (Japan), Fax: (+81) 52‐788‐6200
| | - Masa‐aki Kishida
- Department of Chemistry, School of Science, The University of Tokyo, 7‐3‐1, Hongo, Bunkyo‐Ku, Tokyo 113‐0033 (Japan), Fax: (+81) 3‐5841‐8063
| | - Ryota Sakamoto
- Department of Chemistry, School of Science, The University of Tokyo, 7‐3‐1, Hongo, Bunkyo‐Ku, Tokyo 113‐0033 (Japan), Fax: (+81) 3‐5841‐8063
| | - Hiroshi Nishihara
- Department of Chemistry, School of Science, The University of Tokyo, 7‐3‐1, Hongo, Bunkyo‐Ku, Tokyo 113‐0033 (Japan), Fax: (+81) 3‐5841‐8063
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Narth C, Gillet N, Lévy B, Demachy I, de la Lande A. Investigation of the molecular mechanisms of electronic decoherence within a quinone cofactor. CAN J CHEM 2013. [DOI: 10.1139/cjc-2012-0529] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The notion of decoherence is particularly adapted to discuss the quantum-to-classical transition in the context of chemical reactions. Decoherence can be modeled by computing the time evolution of nuclear wave packets evolving on distinct potential energy surfaces, here using density functional theory (DFT) and Born–Oppenheimer molecular dynamics simulations. We investigate a redox cofactor of biological interest (tryptophan tryptophylquinone, TTQ) found in the enzyme methylamine dehydrogenase. We also report the first systematic comparison of semi-empirical DFT (tight-binding DFT) and classical force field approaches for estimating decoherence in molecular systems. In the TTQ cofactor, we find that decoherence combines structural and dynamical aspects: it is initiated by the divergent motions of few atoms and then propagates dynamically to the remaining atoms. It is the mass effect of all the atoms that leads to decoherence within a few femtosecond.
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Affiliation(s)
- Christophe Narth
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
- Laboratoire de Chimie Théorique, CNRS UMR 7616, Université Pierre et Marie Curie, case courrier 137, 4, Place Jussieu, 75 252 Paris Cedex 05, France
| | - Natacha Gillet
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
| | - Bernard Lévy
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
| | - Isabelle Demachy
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
| | - Aurélien de la Lande
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
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Geng J, Dornevil K, Davidson VL, Liu A. Tryptophan-mediated charge-resonance stabilization in the bis-Fe(IV) redox state of MauG. Proc Natl Acad Sci U S A 2013; 110:9639-44. [PMID: 23720312 PMCID: PMC3683780 DOI: 10.1073/pnas.1301544110] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The diheme enzyme MauG catalyzes posttranslational modifications of a methylamine dehydrogenase precursor protein to generate a tryptophan tryptophylquinone cofactor. The MauG-catalyzed reaction proceeds via a bis-Fe(IV) intermediate in which one heme is present as Fe(IV)=O and the other as Fe(IV) with axial histidine and tyrosine ligation. Herein, a unique near-infrared absorption feature exhibited specifically in bis-Fe(IV) MauG is described, and evidence is presented that it results from a charge-resonance-transition phenomenon. As the two hemes are physically separated by 14.5 Å, a hole-hopping mechanism is proposed in which a tryptophan residue located between the hemes is reversibly oxidized and reduced to increase the effective electronic coupling element and enhance the rate of reversible electron transfer between the hemes in bis-Fe(IV) MauG. Analysis of the MauG structure reveals that electron transfer via this mechanism is rapid enough to enable a charge-resonance stabilization of the bis-Fe(IV) state without direct contact between the hemes. The finding of the charge-resonance-transition phenomenon explains why the bis-Fe(IV) intermediate is stabilized in MauG and does not permanently oxidize its own aromatic residues.
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Affiliation(s)
- Jiafeng Geng
- Department of Chemistry, Center for Diagnostics and Therapeutics, and Molecular Basis of Disease Program, Georgia State University, Atlanta, GA 30303; and
| | - Kednerlin Dornevil
- Department of Chemistry, Center for Diagnostics and Therapeutics, and Molecular Basis of Disease Program, Georgia State University, Atlanta, GA 30303; and
| | - Victor L. Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827
| | - Aimin Liu
- Department of Chemistry, Center for Diagnostics and Therapeutics, and Molecular Basis of Disease Program, Georgia State University, Atlanta, GA 30303; and
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Kawai H, Utamura T, Motoi E, Takahashi T, Sugino H, Tamura M, Ohkita M, Fujiwara K, Saito T, Tsuji T, Suzuki T. Hydrindacene-Based Acetylenic Macrocycles with Horizontally and Vertically Ordered Functionality Arrays. Chemistry 2013; 19:4513-24. [DOI: 10.1002/chem.201200716] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 01/12/2013] [Indexed: 11/11/2022]
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Yang J, Zhang W, Si Y, Zhao Y. Intramolecular Electronic Couplings in Class II/III Organic Mixed-Valence Systems of Bis(1,4-dimethoxybenzene). J Phys Chem B 2012; 116:14126-35. [DOI: 10.1021/jp308242s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Juanhua Yang
- State Key Laboratory of Physical Chemistry
of Solid Surfaces, Fujian Provincial Key Lab of Theoretical
and Computational Chemistry, and College of Chemistry and Chemical
Engineering, Xiamen University, Xiamen
361005, P. R. China
| | - Weiwei Zhang
- State Key Laboratory of Physical Chemistry
of Solid Surfaces, Fujian Provincial Key Lab of Theoretical
and Computational Chemistry, and College of Chemistry and Chemical
Engineering, Xiamen University, Xiamen
361005, P. R. China
| | - Yubing Si
- State Key Laboratory of Physical Chemistry
of Solid Surfaces, Fujian Provincial Key Lab of Theoretical
and Computational Chemistry, and College of Chemistry and Chemical
Engineering, Xiamen University, Xiamen
361005, P. R. China
| | - Yi Zhao
- State Key Laboratory of Physical Chemistry
of Solid Surfaces, Fujian Provincial Key Lab of Theoretical
and Computational Chemistry, and College of Chemistry and Chemical
Engineering, Xiamen University, Xiamen
361005, P. R. China
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39
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Liddle BJ, Wanniarachchi S, Hewage JS, Lindeman SV, Bennett B, Gardinier JR. Electronic communication across diamagnetic metal bridges: a homoleptic gallium(III) complex of a redox-active diarylamido-based ligand and its oxidized derivatives. Inorg Chem 2012; 51:12720-8. [PMID: 23163736 DOI: 10.1021/ic301437f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Complexes with cations of the type [Ga(L)(2)](n+) where L = bis(4-methyl-2-(1H-pyrazol-1-yl)phenyl)amido and n = 1, 2, 3 have been prepared and structurally characterized. The electronic properties of each were probed by electrochemical and spectroscopic means and were interpreted with the aid of density functional theory (DFT) calculations. The dication, best described as [Ga(L(-))(L(0))](2+), is a Robin-Day class II mixed-valence species. As such, a broad, weak, solvent-dependent intervalence charge transfer (IVCT) band was found in the NIR spectrum in the range 6390-6925 cm(-1), depending on the solvent. Band shape analyses and the use of Hush and Marcus relations revealed a modest electronic coupling, H(ab) of about 200 cm(-1), and a large rate constant for electron transfer, k(et), on the order of 10(10) s(-1) between redox active ligands. The dioxidized complex [Ga(L(0))(2)](3+) shows a half-field ΔM(s) = 2 transition in its solid-state X-band electron paramagnetic resonance (EPR) spectrum at 5 K, which indicates that the triplet state is thermally populated. DFT calculations (M06/Def2-SV(P)) suggest that the singlet state is 21.7 cm(-1) lower in energy than the triplet state.
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Affiliation(s)
- Brendan J Liddle
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
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40
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Renz M, Kaupp M. Predicting the localized/delocalized character of mixed-valence diquinone radical anions. Toward the right answer for the right reason. J Phys Chem A 2012; 116:10629-37. [PMID: 23025699 DOI: 10.1021/jp308294r] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Robin-Day class II/III mixed-valence character is established quantum-chemically for a series of mixed-valence diquinone radical anions. Particular emphasis is placed on the radical anion of tetrathiafulvalenedibenzoquinone, Q-TTF-Q, which has recently been used to evaluate constrained density functional approaches (CDFT) and new range hybrid functionals. Using a computational protocol based on hybrid functionals with 35-42% exact-exchange admixture and inclusion of solvent models during the structure optimization, it is demonstrated that a) Q-TTF-Q(•-), 1, and the related diquinone radical anions 2-4 are all delocalized class III species in the gas phase and in nonpolar solvents, in contrast to previous assumptions; b) 1,4,5,8-anthracenetetraone radical anion, 2, remains class III in polar aprotic solvents, c) systems 1, 3 and 4 become class II, providing excellent agreement between computed and experimental intervalence charge-transfer excitations, thermal electron-transfer (ET) barriers and ESR hyperfine couplings. The direct conductor-like screening model for real solvents (D-COSMO-RS) allows the inclusion of specific hydrogen-bonding effects without the computational effort of molecular dynamics simulations and provides increased ET barriers, as well as a predicted incipient symmetry breaking for 2, due to hydrogen bonding in alcohol solvents. For the first time D-COSMO-RS optimizations in solvent mixtures have been evaluated. As previous computational studies of Q-TTF-Q(•-) neglected solvent effects during structure optimizations and obtained charge localization in gas-phase optimizations by CDFT or by exaggerated exact-exchange admixtures, they provided at best the right answer for the wrong reason.
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Affiliation(s)
- Manuel Renz
- Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Sekr. C7, Straße des 17. Juni 135, 10623 Berlin, Germany
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41
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Reuter LG, Bonn AG, Stückl AC, He B, Pati PB, Zade SS, Wenger OS. Charge Delocalization in a Homologous Series of α,α′-Bis(dianisylamino)-Substituted Thiophene Monocations. J Phys Chem A 2012; 116:7345-52. [DOI: 10.1021/jp303989t] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Luisa G. Reuter
- Institut für
Anorganische
Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Annabell G. Bonn
- Institut für
Anorganische
Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - A. Claudia Stückl
- Institut für
Anorganische
Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Bice He
- Institut für
Anorganische
Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Palas Baran Pati
- Department of Chemical Sciences, Indian Institute of Science Education and Research,
Kolkata, P.O. BCKV Campus Main Office, Mohanpur 741252, Nadia, West
Bengal, India
| | - Sanjio S. Zade
- Department of Chemical Sciences, Indian Institute of Science Education and Research,
Kolkata, P.O. BCKV Campus Main Office, Mohanpur 741252, Nadia, West
Bengal, India
| | - Oliver S. Wenger
- Institut für
Anorganische
Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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Mechanically induced intramolecular electron transfer in a mixed-valence molecular shuttle. Proc Natl Acad Sci U S A 2012; 109:11546-51. [PMID: 22685213 DOI: 10.1073/pnas.1201561109] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kinetics and thermodynamics of intramolecular electron transfer (IET) can be subjected to redox control in a bistable [2]rotaxane comprised of a dumbbell component containing an electron-rich 1,5-dioxynaphthalene (DNP) unit and an electron-poor phenylene-bridged bipyridinium (P-BIPY(2+)) unit and a cyclobis (paraquat-p-phenylene) (CBPQT(4+)) ring component. The [2]rotaxane exists in the ground-state co-conformation (GSCC) wherein the CBPQT(4+) ring encircles the DNP unit. Reduction of the CBPQT(4+) leads to the CBPQT(2(•+)) diradical dication while the P-BIPY(2+) unit is reduced to its P-BIPY(•+) radical cation. A radical-state co-conformation (RSCC) results from movement of the CBPQT(2(•+)) ring along the dumbbell to surround the P-BIPY(•+) unit. This shuttling event induces IET to occur between the pyridinium redox centers of the P-BIPY(•+) unit, a property which is absent between these redox centers in the free dumbbell and in the 1:1 complex formed between the CBPQT(2(•+)) ring and the radical cation of methyl-phenylene-viologen (MPV(•+)). Using electron paramagnetic resonance (EPR) spectroscopy, the process of IET was investigated by monitoring the line broadening at varying temperatures and determining the rate constant (k(ET) = 1.33 x 10(7) s(-1)) and activation energy (ΔG(‡) = 1.01 kcal mol(-1)) for electron transfer. These values were compared to the corresponding values predicted, using the optical absorption spectra and Marcus-Hush theory.
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Mechouet M, Perruchot C, Maurel F, Aeiyach S, Bucher C, Chardon S, Jouini M. Intervalence charge transfer in mixed valence compound modified by the formation of a supramolecular complex. J Phys Chem A 2012; 116:970-8. [PMID: 22175529 DOI: 10.1021/jp207518r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electrochemical and spectroelectrochemical properties of N,N-diphenyl-1,4-phenylenediamine (PDA) were investigated in the absence and in the presence of 18-crown-6-ether (18C6) or dibenzo 24-crown-8-ether (DB24C8), in a solution of tetrabutylammonium hexafluorophosphate (TBAPF6) in acetonitrile and in the presence of trifluoroacetic acid (TFA) only for 18C6. In neutral acetonitrile, PDA undergoes two reversible oxidation processes, which lead first to the formation of the cation-radical considered as mixed valence (MV) compound, and then to the dicationic species. When 18C6 is added in the medium and depending on 18C6 concentration, cyclic voltammetry shows a marked shift to more cathodic potentials of the current waves of the second redox process only. This is attributed to a strong interaction between the PDA(+2) dication and two 18C6 molecules, leading to the formation of a supramolecular complex with an association constant value K(a) = 7.0 × 10(7) M(-2). The interaction of 18C6 with PDA(+2) dication has a direct effect on the PDA(+.) cation-radical corresponding to a decrease in the lifetime of the MV compound and of the intramolecular electron transfer rate when 18C6 is present. Indeed, it results in a large decrease in the intervalence charge transfer (IV-CT) between the two amine centers in the MV compound (k(th) = 1.35 × 10(10) s(-1) in 18C6-free neutral solution containing 5.0 × 10(-4) M PDA, and k(th) = 3.6 × 10(9) s(-1) in the same medium at [18C6]/[PDA] = 20/1). And the comproportionation constant K(co) falls from 6.0 × 10(6) in 18C6-free solution to 1.6 × 10(3) at [18C6]/[PDA] = 20/1. In acidified acetonitrile and when TFA concentration is increased, PDA still shows the two successive and reversible oxidation processes, but both are shifted to more anodic potentials. However, when 18C6 is added, the two oxidation waves shift to more cathodic potentials, indicating an interaction of all protonated PDA redox states with 18C6, resulting in the formation of supramolecular complexes. In the presence of TFA, the value of K(co) is decreased to 4.3 × 10(4), but it remains unchanged when 18C6 is added, indicating no change in the lifetime of the MV compound. In this medium, IV-CT in the MV compound is greater with 18C6 (k(th) = 2.3 × 10(10) s(-1) for [18C6]/[PDA] = 20/1) than without (k(th) = 1.4 × 10(9) s(-1)), which indicates a more important IV-CT rate when 18C6 is present. The results show for the first time that is it possible to control the IV-CT rate, through the lifetime and the potential range where the MV compound is the most important. This control is not obtained as usual by chemical modification of the structure of the starting molecule, but by varying either the acidity or the 18C6 concentration as external stimuli, which lead to reversible formation/dissociation of a supramolecular complex species. Moreover, we also studied the electrochemical properties of PDA in the presence of wider crown ether such as DB24C8. We showed that PDA undergoes the same electrochemical behavior with DB24C8 than with 18C6 in neutral organic medium (K(a) = 2.9 × 10(3) M(-1)). This result suggests that the complexation between the electrogenerated PDA(+2) dication and the crown ethers may occur through face-to-face mode rather than rotaxane mode even with DB24C8 which is supposed to form inclusion complexes.
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Affiliation(s)
- Mourad Mechouet
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Interfaces, Traitements, Organisation et Dynamique des Systèmes, UMR 7086, Paris, France
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Heckmann A, Lambert C. Organic Mixed-Valence Compounds: A Playground for Electrons and Holes. Angew Chem Int Ed Engl 2011; 51:326-92. [DOI: 10.1002/anie.201100944] [Citation(s) in RCA: 414] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Indexed: 11/05/2022]
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Heckmann A, Lambert C. Organische gemischtvalente Verbindungen: ein Spielplatz für Elektronen und Löcher. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201100944] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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He B, Wenger OS. Photoswitchable Organic Mixed Valence in Dithienylcyclopentene Systems with Tertiary Amine Redox Centers. J Am Chem Soc 2011; 133:17027-36. [DOI: 10.1021/ja207025x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bice He
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Oliver S. Wenger
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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47
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Electron delocalization in vinyl ruthenium substituted cyclophanes: Assessment of the through-space and the through-bond pathways. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.06.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Mücke P, Linseis M, Záliš S, Winter RF. Vinyl-ruthenium entities as markers for intramolecular electron transfer processes. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.03.071] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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49
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50
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Affiliation(s)
- Jihane Hankache
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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