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Bens T, Walter RRM, Beerhues J, Schmitt M, Krossing I, Sarkar B. The Best of Both Worlds: Combining the Power of MICs and WCAs To Generate Stable and Crystalline Cr I -Tetracarbonyl Complexes with π-Accepting Ligands. Chemistry 2023; 29:e202301205. [PMID: 37212248 DOI: 10.1002/chem.202301205] [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: 04/17/2023] [Revised: 05/11/2023] [Accepted: 05/22/2023] [Indexed: 05/23/2023]
Abstract
Here we present stable and crystalline chromium(I) tetracarbonyl complexes with pyridyl-MIC (MIC=mesoionic carbene) ligands and weakly coordinating anions (WCA=[Al(ORF )4 ]- , RF =C(CF3 )3 and BArF =[B(ArF )4 ]- , ArF =3,5-(CF3 )2 C6 H3 ). The complexes were fully characterized via crystallographic, spectroscopic and theoretical methods. The influence of counter anions on the IR and EPR spectroscopic properties of the CrI complexes was investigated, and the electronic innocence versus non-innocence of WCAs was probed. These are the first examples of stable and crystalline [Cr(CO)4 ]+ complexes with a chelatingπ - ${\pi -}$ accepting ligand, and the data presented here are of relevance for both the photochemical and the electrochemical properties of these classes of compounds.
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Affiliation(s)
- Tobias Bens
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Robert R M Walter
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Julia Beerhues
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
- Current Address: Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Paisos Catalans 16, 43007, Tarragona, Spain
| | - Manuel Schmitt
- Institut für Anorganische und Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Ingo Krossing
- Institut für Anorganische und Freiburger Materialforschungszentrum (FMF), Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
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Bullock JP, Lee CY, Hagan B, Madhani H, Ulrich J. Electrochemical Oxidation of W(CO)4(LL): Generation, Characterization, and Reactivity of [W(CO)4(LL)]+ (LL=α-diimine ligands). Aust J Chem 2017. [DOI: 10.1071/ch17256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The electrochemistry of a series of W(CO)4(LL) complexes, where LL is an aromatic α-diimine ligand, was examined in coordinating and weakly coordinating media using several techniques. These compounds undergo metal-centred one-electron oxidations and the electrogenerated radical cations undergo a range of subsequent chemical steps, the nature of which depends on the substituents of the α-diimine ligand and the presence of coordinating species. In CH2Cl2/TBAPF6, where TBAPF6 is n-tetrabutylammonium hexaflurophosphate, the bulk oxidations are partially reversible at scan rates of 0.25 V s−1; the resulting tungsten(i) radicals react via disproportionation and loss of carbonyl, the rate constants for which were measured by double-potential step chronocoulometry. Large-amplitude a.c. voltammetry experiments suggest that the one-electron oxidized species are in equilibrium with the corresponding disproportionation products. Steric crowding of the metal centre prolongs the lifetime of the radical cations, allowing the infrared spectroelectrochemical characterization of two [W(CO)4(LL)]+ species. Electrogenerated [W(CO)4(LL)]+ cations are highly susceptible to attack by potential ligands; oxidations performed in CH3CN/TBAPF6, for example, were chemically irreversible. Kinetic studies in weakly coordinating media show that near-stoichiometric amounts of added pyridine and acetonitrile are enough to greatly diminish the reversibility of the bulk oxidations; the dominant path of the coupled chemistry depends on the ligand strength, with substitution being the major reaction with added pyridine, whereas disproportionation is favoured by the presence of acetonitrile. A reaction scheme that provides an overall framework of the reactions followed by the radical cations is presented and discussed in the context of the previously observed chemistry of the molybdenum analogues.
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Üstün E, Çol Ayvaz M, Sönmez Çelebi M, Aşcı G, Demir S, Özdemir İ. Structure, CO-releasing property, electrochemistry, DFT calculation, and antioxidant activity of benzimidazole derivative substituted [Mn(CO)3(bpy)L]PF6 type novel manganese complexes. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.05.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Bator G, Sobczyk L, Sawka-Dobrowolska W, Wuttke J, Pawlukojć A, Grech E, Nowicka-Scheibe J. Structural, spectroscopic and theoretical studies on 3,4,7,8-tetramethyl-1,10-phenantroline complex with picric acid. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2012.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Scarborough CC, Sproules S, Weyhermüller T, DeBeer S, Wieghardt K. Electronic and Molecular Structures of the Members of the Electron Transfer Series [Cr(tbpy)3]n (n = 3+, 2+, 1+, 0): An X-ray Absorption Spectroscopic and Density Functional Theoretical Study. Inorg Chem 2011; 50:12446-62. [DOI: 10.1021/ic201123x] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher C. Scarborough
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
| | - Stephen Sproules
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca,
New York 14853, United States
| | - Karl Wieghardt
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
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Scarborough CC, Wieghardt K. Electronic structure of 2,2'-bipyridine organotransition-metal complexes. Establishing the ligand oxidation level by density functional theoretical calculations. Inorg Chem 2011; 50:9773-93. [PMID: 21678919 DOI: 10.1021/ic2005419] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A density functional theoretical (DFT) study (B3LYP) has been carried out on 20 organometallic complexes containing η(5)- and/or η(3)-coordinated cyclopentadienyl anions (Cp(-)) and 2,2'-bipyridine (bpy) ligand(s) at varying oxidation levels, i.e., as the neutral ligand (bpy(0)), as the π-radical monoanion (bpy(•-))(-), or as the diamagnetic dianion (bpy(2-))(2-). The molecular and electronic structures of these species in their ground states and, in some cases, their first excited states have been calculated using broken-symmetry methodology. The results are compared with experimental structural and spectroscopic data (where available) in order to validate the DFT computational approach. The following electron-transfer series and complexes have been studied: [(Cp)(2)V(bpy)](0,+,2+) (1-3), [(Cp)(2)Ti(bpy)](-,0,+,2+) (4-7), [(Cp)(2)Ti(biquinoline)](0,+) (8 and 9), [(Cp*)(2)Ti(bpy)](0) (10) (Cp* = pentamethylcyclopentadienyl anion), [Cp*Co(bpy)](0,+) (11 and 12), [Cp*Co(bpy)Cl](+,0) (13 and 14), [Fe(toluene)(bpy)](0) (15), [Cp*Ru(bpy)](-) (16), [(Cp)(2)Zr(bpy)](0) (17), and [Mn(CO)(3)(bpy)](-) (18). In order to test the predictive power of our computations, we have also calculated the molecular and electronic structures of two complexes, A and B, namely, the diamagnetic dimer [Cp*Sc(bpy)(μ-Cl)](2) (A) and the paramagnetic (at 25 °C) mononuclear species [(η(5)-C(5)H(4)(CH(2))(2)N(CH(3))(2))Sc((m)bpy)(2)] (B). The crystallographically observed intramolecular π-π interaction of two N,N'-coordinated π-radical anions in A leading to an S = 0 ground state is reliably reproduced. Similarly, the small singlet-triplet gap of ~600 cm(-1) between two antiferromagnetically coupled (bpy(•-))(-) ligands in B, two ferromagnetically coupled radical anions in the triplet excited state of B, and the structures of A and B is reproduced. Therefore, we are confident that we can present computationally obtained, detailed electronic structures for complexes 1-18. We show that N,N'-coordinated neutral bpy(0) ligands behave as very weak π acceptors (if at all), whereas the (bpy(2-))(2-) dianions are strong π-donor ligands.
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Affiliation(s)
- Christopher C Scarborough
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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Bullock JP, Carter E, Johnson R, Kennedy AT, Key SE, Kraft BJ, Saxon D, Underwood P. Reactivity of Electrochemically Generated Rhenium (II) Tricarbonyl α-Diimine Complexes: A Reinvestigation of the Oxidation of Luminescent Re(CO)3(α-Diimine)Cl and Related Compounds. Inorg Chem 2008; 47:7880-7. [DOI: 10.1021/ic800530n] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John P. Bullock
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - Eric Carter
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - Ryan Johnson
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - Abigail T. Kennedy
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - Sarah E. Key
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - Brian J. Kraft
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - David Saxon
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
| | - Patrick Underwood
- The Division of Natural Science and Mathematics, Bennington College, Bennington, Vermont 05201, and The Department of Chemistry, Central Washington University, Ellensburg, Washington 98926
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Electrochemical oxidation of Mo(CO)4(LL) and Mo(CO)3(LL)(CH3CN): Generation, infrared characterization, and reactivity of [Mo(CO)4(LL)]+ and [Mo(CO)3(LL)(CH3CN)]+ (LL=2,2′-bipyridine, 1,10-phenanthroline and related ligands). Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2007.04.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Organometallic Chemistry of Polypyridine Ligands I. ADVANCES IN HETEROCYCLIC CHEMISTRY 2007. [DOI: 10.1016/s0065-2725(06)93004-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Baldoli C, Cerea P, Falciola L, Giannini C, Licandro E, Maiorana S, Mussini P, Perdicchia D. The electrochemical activity of heteroatom-stabilized Fischer-type carbene complexes. J Organomet Chem 2005. [DOI: 10.1016/j.jorganchem.2005.07.048] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zális S, Farrell IR, Vlcek A. The involvement of metal-to-CO charge transfer and ligand-field excited states in the spectroscopy and photochemistry of mixed-ligand metal carbonyls. A theoretical and spectroscopic study of [W(CO)(4)(1,2-ethylenediamine)] and [W(CO)(4)(N,N'-bis-alkyl-1,4-diazabutadiene)]. J Am Chem Soc 2003; 125:4580-92. [PMID: 12683830 DOI: 10.1021/ja021022j] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new interpretation of the electronic spectroscopy, photochemistry, and photophysics of group 6 metal cis-tetracarbonyls [M(CO)(4)L(2)] is proposed, that is based on an interplay between M --> L and M --> CO MLCT excited states. TD-DFT and resonance Raman spectroscopy show that the lowest allowed electronic transition of [W(CO)(4)(en)] (en = 1,2-ethylenediamine) has a W(CO(eq))(2) --> CO(ax) charge-transfer character, whereby the electron density is transferred from the equatorial W(CO(eq))(2) moiety to pi orbitals of the axial CO ligands, with a net decrease of electron density on the W atom. The lowest, emissive excited state of [W(CO)(4)(en)] was identified as a spin-triplet W(CO(eq))(2) --> CO(ax) CT excited state both computationally and by picosecond time-resolved IR spectroscopy. This state undergoes 1.5 ps vibrational relaxation/solvation and decays to the ground state with a approximately 160 ps lifetime. The nu(CO) wavenumbers and IR intensity pattern calculated by DFT for the triplet W(CO(eq))(2) --> CO(ax) CT excited state match well the experimental time-resolved spectrum. For [W(CO)(4)(R-DAB)] (R-DAB = N,N'-bis-alkyl-1,4-diazabutadiene), the W(CO(eq))(2) --> CO(ax) CT transition follows in energy the W --> DAB MLCT transition, and the emissive W(CO(eq))(2) --> CO(ax) CT triplet state occurs just above the manifold of triplet W --> DAB MLCT states. No LF electronic transitions were calculated to occur in a relevant energetic range for either complex. Molecular orbitals of both complexes are highly delocalized. The 5d(W) character is distributed over many molecular orbitals, while neither of them contains a predominant metal-ligand sigma 5d(W) component, contrary to predictions of the traditional ligand-field approach. The important spectroscopic, photochemical, and photophysical roles of M(CO(eq))(2) --> CO(ax) CT excited states and the limited validity of ligand field arguments can be generalized to other mixed-ligand carbonyl complexes.
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Affiliation(s)
- Stanislav Zális
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-182 23 Prague, Czech Republic
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