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Hess KM, Leach IF, Wijtenhorst L, Lee H, Klein JEMN. Valence Tautomerism Induced Proton Coupled Electron Transfer:X-H Bond Oxidation with a Dinuclear Au(II) Hydroxide Complex. Angew Chem Int Ed Engl 2024; 63:e202318916. [PMID: 38324462 DOI: 10.1002/anie.202318916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 02/09/2024]
Abstract
We report the preparation and characterization of the dinuclear AuII hydroxide complex AuII 2(L)2(OH)2 (L=N,N'-bis (2,6-dimethyl) phenylformamidinate) and study its reactivity towards weak X-H bonds. Through the interplay of kinetic analysis and computational studies, we demonstrate that the oxidation of cyclohexadiene follows a concerted proton-coupled electron transfer (cPCET) mechanism, a rare type of reactivity for Au complexes. We find that the Au-Au σ-bond undergoes polarization in the PCET event leading to an adjustment of oxidation levels for both Au centers prior to C(sp3)-H bond cleavage. We thus describe the oxidation event as a valence tautomerism-induced PCET where the basicity of one reduced Au-OH unit provides a proton acceptor and the second more oxidized Au center serves as an electron acceptor. The coordination of these events allows for unprecedented radical-type reactivity by a closed shell AuII complex.
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Affiliation(s)
- Kristopher M Hess
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Isaac F Leach
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Lisa Wijtenhorst
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Hangyul Lee
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
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2
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Geniman MP, Morozova OB, Lukzen NN, Grampp G, Yurkovskaya AV. Marcus Cross-Relationship Probed by Time-Resolved CIDNP. Int J Mol Sci 2023; 24:13860. [PMID: 37762162 PMCID: PMC10530771 DOI: 10.3390/ijms241813860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
The time-resolved CIDNP method can provide information about degenerate exchange reactions (DEEs) involving short-lived radicals. In the temperature range from 8 to 65 °C, the DEE reactions of the guanosine-5'-monophosphate anion GMP(-H)- with the neutral radical GMP(-H)•, of the N-acetyl tyrosine anion N-AcTyrO- with a neutral radical N-AcTyrO•, and of the tyrosine anion TyrO- with a neutral radical TyrO• were studied. In all the studied cases, the radicals were formed in the reaction of quenching triplet 2,2'-dipyridyl. The reorganization energies were obtained from Arrhenius plots. The rate constant of the reductive electron transfer reaction in the pair GMP(-H)•/TyrO- was determined at T = 25 °C. Rate constants of the GMP(-H)• radical reduction reactions with TyrO- and N-AcTyrO- anions calculated by the Marcus cross-relation differ from the experimental ones by two orders of magnitude. The rate constants of several other electron transfer reactions involving GMP(-H)-/GMP(-H)•, N-AcTyrO-/N-AcTyrO•, and TyrO-/TyrO• pairs calculated by cross-relation agree well with the experimental values. The rate of nuclear paramagnetic relaxation was found for the 3,5 and β-protons of TyrO• and N-AcTyrO•, the 8-proton of GMP(-H)•, and the 3,4-protons of DPH• at each temperature. In all cases, the dependences of the rate of nuclear paramagnetic relaxation on temperature are described by the Arrhenius dependence.
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Affiliation(s)
- Maksim P. Geniman
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Olga B. Morozova
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
| | - Nikita N. Lukzen
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Günter Grampp
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse, 9, A-8010 Graz, Austria;
| | - Alexandra V. Yurkovskaya
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
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3
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Bhowmick R, Roy Chowdhury S, Vlaisavljevich B. Molecular Geometry and Electronic Structure of Copper Corroles. Inorg Chem 2023; 62:13877-13891. [PMID: 37590888 DOI: 10.1021/acs.inorgchem.3c01779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Copper corroles are known for their unique multiconfigurational electronic structures in the ground state, which arise from the transfer of electrons from the π orbitals of the corrole to the d-orbital of copper. While density functional theory (DFT) provides reasonably good molecular geometries, the determination of the ground spin state and the associated energetics is heavily influenced by functional choice, particularly the percentage of the Hartree-Fock exchange. Using extended multireference perturbation theory methods (XMS-CASPT2), the functional choice can be assessed. The molecular geometries and electronic structures of both the unsubstituted and the meso-triphenyl copper corroles were investigated. A minimal active space was employed for structural characterization, while larger active spaces are required to examine the electronic structure. The XMS-CASPT2 investigations conclusively identify the ground electronic state as a multiconfigurational singlet (S0) with three dominant electronic configurations in its lowest energy and characteristic saddled structure. In contrast, the planar geometry corresponds to the triplet state (T0), which is approximately 5 kcal/mol higher in energy compared to the S0 state for both the bare and substituted copper corroles. Notably, the planarity of the T0 geometry is reduced in the substituted corrole compared with that in the unsubstituted one. By analyzing the potential energy surface (PES) between the S0 and T0 geometries using XMS-CASPT2, the multiconfigurational electronic structure is shown to transition toward a single electron configuration as the saddling angle decreases (i.e., as one approaches the planar geometry). Despite the ability of the functionals to reproduce the minimum energy structures, only the TPSSh-D3 PES is reasonably close to the XMS-CASPT2 surface. Significant deviations along the PES are observed with other functionals.
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Affiliation(s)
- Rina Bhowmick
- Department of Chemistry, University of South Dakota, Vermillion, South Dakota 57069, United States
| | - Sabyasachi Roy Chowdhury
- Department of Chemistry, University of South Dakota, Vermillion, South Dakota 57069, United States
| | - Bess Vlaisavljevich
- Department of Chemistry, University of South Dakota, Vermillion, South Dakota 57069, United States
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Liu Y, Resch SG, Chen H, Dechert S, Demeshko S, Bill E, Ye S, Meyer F. Fully Delocalized Mixed-Valent Cu 1.5 Cu 1.5 Complex: Strong Cu-Cu interaction and Fast Electron Self-Exchange Rate Despite Large Structural Changes. Angew Chem Int Ed Engl 2023; 62:e202215840. [PMID: 36504436 DOI: 10.1002/anie.202215840] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
A flexible macrocyclic ligand with two tridentate {CNC} compartments can host two Cu ions in reversibly interconvertible states, CuI CuI (1) and mixed-valent Cu1.5 Cu1.5 (2). They were characterized by XRD and multiple spectroscopic methods, including EPR, UV/Vis absorption and MCD, in combination with TD-DFT and CASSCF calculations. 2 features a short Cu⋅⋅⋅Cu distance (≈2.5 Å; compared to ≈4.0 Å in 1) and a very high delocalization energy of 13 000 cm-1 , comparable to the mixed-valent state of the biological CuA site. Electron self-exchange between 1 and 2 is rapid despite large structural reorganization, and is proposed to proceed via a sequential mechanism involving an active conformer of 1, viz. 1'; the latter has been characterized by XRD. Such electron transfer (ET) process is reminiscent of the conformationally gated ET proposed for biological systems. This redox couple is a unique pair of flexible dicopper complexes, achieving fast electron self-exchange closely related to the function of the CuA site.
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Affiliation(s)
- Yang Liu
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Stefan G Resch
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Haowei Chen
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.,Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Sebastian Dechert
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077, Göttingen, Germany
| | - Eckhard Bill
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077, Göttingen, Germany
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5
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McKee ML. Exploring the Reaction Mechanism of C-H Oxidation by Copper-Salen Complexes. J Phys Chem A 2022; 126:4969-4980. [PMID: 35861503 DOI: 10.1021/acs.jpca.2c03344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanism of C-H oxidation of propylene (C3H6) and 1-phenyl-1-pentyne (C3H7-C≡C-Ph) by HOOR (R═Me, tBu) and 3O2 by a copper-salen complex was explored by computations. The most noteworthy step is the complexation of two Cu salens to the peroxide to form either the LCuOH/LCuOR pair or an OH-bridged complex LCu(μ-OH)CuL plus OR. The latter pathway involves an avoided crossing of two triplet electronic states. The LCuOH complex can abstract a hydrogen atom from C3H6 and the C3H5 radical plus 3O2 forms the complex LCuOOC3H5. Migration of a hydrogen to the proximal oxygen atom reforms LCuOH and acrolein HC(O)CH═CH2.
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Affiliation(s)
- Michael L McKee
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama36849, United States
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6
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Fort MJ, Click SM, Robinson EH, He FMC, Bernhardt PV, Rosenthal SJ, Macdonald JE. Minimizing the Reorganization Energy of Cobalt Redox Mediators Maximizes Charge Transfer Rates from Quantum Dots. Angew Chem Int Ed Engl 2022; 61:e202202322. [DOI: 10.1002/anie.202202322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Madeleine J. Fort
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Sophia M. Click
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Evan H. Robinson
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Felix M. C. He
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Sandra J. Rosenthal
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Janet E. Macdonald
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
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7
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Fort MJ, Click SM, Robinson EH, He FMC, Bernhardt PV, Rosenthal SJ, Macdonald JE. Minimizing the Reorganization Energy of Cobalt Redox Mediators Maximizes Charge Transfer Rates from Quantum Dots. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Madeleine J. Fort
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Sophia M. Click
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Evan H. Robinson
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Felix M. C. He
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane Queensland 4072 Australia
| | - Sandra J. Rosenthal
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
| | - Janet E. Macdonald
- Department of Chemistry Vanderbilt Institute of Nanoscale Science and Engineering Vanderbilt University Nashville TN 37235 USA
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8
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Muñoz-García AB, Benesperi I, Boschloo G, Concepcion JJ, Delcamp JH, Gibson EA, Meyer GJ, Pavone M, Pettersson H, Hagfeldt A, Freitag M. Dye-sensitized solar cells strike back. Chem Soc Rev 2021; 50:12450-12550. [PMID: 34590638 PMCID: PMC8591630 DOI: 10.1039/d0cs01336f] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Indexed: 12/28/2022]
Abstract
Dye-sensitized solar cells (DSCs) are celebrating their 30th birthday and they are attracting a wealth of research efforts aimed at unleashing their full potential. In recent years, DSCs and dye-sensitized photoelectrochemical cells (DSPECs) have experienced a renaissance as the best technology for several niche applications that take advantage of DSCs' unique combination of properties: at low cost, they are composed of non-toxic materials, are colorful, transparent, and very efficient in low light conditions. This review summarizes the advancements in the field over the last decade, encompassing all aspects of the DSC technology: theoretical studies, characterization techniques, materials, applications as solar cells and as drivers for the synthesis of solar fuels, and commercialization efforts from various companies.
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Affiliation(s)
- Ana Belén Muñoz-García
- Department of Physics "Ettore Pancini", University of Naples Federico II, 80126 Naples, Italy
| | - Iacopo Benesperi
- School of Natural and Environmental Science, Newcastle University, Bedson Building, NE1 7RU Newcastle upon Tyne, UK.
| | - Gerrit Boschloo
- Department of Chemistry, Ångström Laboratory, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden.
| | - Javier J Concepcion
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Jared H Delcamp
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Elizabeth A Gibson
- School of Natural and Environmental Science, Newcastle University, Bedson Building, NE1 7RU Newcastle upon Tyne, UK.
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Michele Pavone
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | | | - Anders Hagfeldt
- Department of Chemistry, Ångström Laboratory, Uppsala University, P.O. Box 523, 751 20 Uppsala, Sweden.
- University Management and Management Council, Vice Chancellor, Uppsala University, Segerstedthuset, 752 37 Uppsala, Sweden
| | - Marina Freitag
- School of Natural and Environmental Science, Newcastle University, Bedson Building, NE1 7RU Newcastle upon Tyne, UK.
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9
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Liu H, Shen Q. Well-defined organometallic Copper(III) complexes: Preparation, characterization and reactivity. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213923] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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10
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Khan FST, Waldbusser AL, Carrasco MC, Pourhadi H, Hematian S. Synthetic, spectroscopic, structural, and electrochemical investigations of ferricenium derivatives with weakly coordinating anions: ion pairing, substituent, and solvent effects. Dalton Trans 2021; 50:7433-7455. [PMID: 33970173 DOI: 10.1039/d1dt01192h] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A facile and effective strategy for the preparation of a series of ferricenium complexes bearing either electron-donating or electron-withdrawing substituents with weakly coordinating anions such as [B(C6F5)4]- or SbF6- is reported. These systems were thoroughly investigated for their ground state electronic structures in both solution and solid states using infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies as well as single crystal X-ray crystallography and electrochemical measurements. The X-ray structures of the six electron-deficient ferricenium derivatives are of particular interest as only a handful (∼5) of such derivatives have been structurally characterized to date. Comparison of the structural data for both neutral and oxidized derivatives reveals that the nature of the substituents on the cyclopentadienyl (Cp) ligands displays a more significant impact on the metal-ligand separations (FeCt) in the oxidized species than in their neutral analogs. Our 1H-NMR measurements corroborate that in the neutral ferrocene derivatives, electron-donating ring substitutions lead to a greater shielding of the ring protons while electron-withdrawing groups via induction deshield the nearby ring protons. However, the data for the paramagnetic ferricenium derivatives reveals that this substitutional behavior is more complex and fundamentally reversed, which is further supported by our structural studies. We ascribe this reversal of behavior in the ferricenium derivatives to the δ back-donation from the iron atom into the Cp rings which can lead to the overall shielding of the ring protons. Interestingly, our NMR results for the electron-deficient ferricenium derivatives in solution also indicate a direct correlation between the solvent dielectric constant and the energy barrier for rotation around the metal-ligand bond in these systems, whereas such a correlation is absent or not significant in the case of the electron-rich ferricenium species or the corresponding neutral ferrocene analogs. In this work, we also present the electrochemical behavior of the corresponding ferricenium/ferrocene redox couples including potential values (E1/2), peak-to-peak separation (ΔE1/2), and diffusion coefficients (D) of the redox active species in order to provide a concise outline of these data in one place. Our electrochemical studies involved three different solvents and two supporting electrolytes. Notably, our findings point to the significant effect of ion-pairing in lowering the energy necessary for reduction of the ferricenium ion and E1/2 in lower-polarity media. This has significant implications in applications of the ferrocene or ferricenium derivatives as redox agents in low-polarity solvents where an accurate determination of redox potential is critical.
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Affiliation(s)
- Firoz Shah Tuglak Khan
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Amy L Waldbusser
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Maria C Carrasco
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Hadi Pourhadi
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Shabnam Hematian
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
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12
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Wu W, De Hont JT, Parveen R, Vlaisavljevich B, Tolman WB. Sulfur-Containing Analogues of the Reactive [CuOH] 2+ Core. Inorg Chem 2021; 60:5217-5223. [PMID: 33733755 DOI: 10.1021/acs.inorgchem.1c00216] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
With the aim of drawing comparisons to the highly reactive complex LCuOH (L = bis(2,6-diisopropylphenylcarboxamido)pyridine), the complexes [Bu4N][LCuSR] (R = H or Ph) were prepared, characterized by spectroscopy and X-ray crystallography, and oxidized at low temperature to generate the species assigned as LCuSR on the basis of spectroscopy and theory. Consistent with the smaller electronegativity of S versus O, redox potentials for the LCuSR-/0 couples were ∼50 mV lower than for LCuOH-/0, and the rates of the proton-coupled electron transfer reactions of LCuSR with anhydrous 1-hydroxy-2,2,6,6-tetramethyl-piperidine at -80 °C were significantly slower (by more than 100 times) than the same reaction of LCuOH. Density functional theory (DFT) and time-dependent DFT calculations on LCuZ (Z = OH, SH, SPh) revealed subtle differences in structural and UV-visible parameters. Further comparison to complexes with Z = F, Cl, and Br using complete active space (CAS) self-consistent field and localized orbital CAS configuration interaction calculations along with a valence-bond-like interpretation of the wave functions showed differences with previously reported results ( J. Am. Chem. Soc. 2020, 142, 8514), and argue for a consistent electronic structure across the entire series of complexes, rather than a change in the nature of the ligand field arrangement for Z = F.
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Affiliation(s)
- Wen Wu
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
| | - Jacqui Tehranchi De Hont
- Department of Chemistry, University of Minnesota, 207 Pleasant Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Riffat Parveen
- University of South Dakota, 414 E. Clark Street, Vermillion, South Dakota 57069, United States
| | - Bess Vlaisavljevich
- University of South Dakota, 414 E. Clark Street, Vermillion, South Dakota 57069, United States
| | - William B Tolman
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
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13
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Krishnan VM, Shopov DY, Bouchey CJ, Bailey WD, Parveen R, Vlaisavljevich B, Tolman WB. Structural Characterization of the [CuOR] 2+ Core. J Am Chem Soc 2021; 143:3295-3299. [PMID: 33621089 DOI: 10.1021/jacs.0c13470] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Formal Cu(III) complexes bearing an oxygen-based auxiliary ligand ([CuOR]2+, R = H or CH2CF3) were stabilized by modulating the donor character of supporting ligand LY (LY = 4-Y, N,N'-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamide, Y = H or OMe) and/or the basicity of the auxiliary ligand, enabling the first characterization of these typically highly reactive cores by NMR spectroscopy and X-ray crystallography. Enhanced lifetimes in solution and slowed rates of PCET with a phenol substrate were observed. NMR spectra corroborate the S = 0 ground states of the complexes, and X-ray structures reveal shortened Cu-ligand bond distances that match well with theory.
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Affiliation(s)
- V Mahesh Krishnan
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
| | - Dimitar Y Shopov
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
| | - Caitlin J Bouchey
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
| | - Wilson D Bailey
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
| | - Riffat Parveen
- University of South Dakota, 414 E. Clark Street, Vermillion, South Dakota 57069, United States
| | - Bess Vlaisavljevich
- University of South Dakota, 414 E. Clark Street, Vermillion, South Dakota 57069, United States
| | - William B Tolman
- Department of Chemistry, Washington University in St. Louis, One Brookings Hall, Campus Box 1134, St. Louis, Missouri 63130-4899, United States
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14
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Zhang W, Moore CE, Zhang S. Encapsulation of tricopper cluster in a synthetic cryptand enables facile redox processes from Cu ICu ICu I to Cu IICu IICu II states. Chem Sci 2020; 12:2986-2992. [PMID: 34164067 PMCID: PMC8179370 DOI: 10.1039/d0sc05441k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
One-pot reaction of tris(2-aminoethyl)amine (TREN), [CuI(MeCN)4]PF6, and paraformaldehyde affords a mixed-valent [TREN4CuIICuICuI(μ3-OH)](PF6)3 complex. The macrocyclic azacryptand TREN4 contains four TREN motifs, three of which provide a bowl-shape binding pocket for the [Cu3(μ3-OH)]3+ core. The fourth TREN caps on top of the tricopper cluster to form a cryptand, imposing conformational constraints and preventing solvent interaction. Contrasting the limited redox capability of synthetic tricopper complexes reported so far, [TREN4CuIICuICuI(μ3-OH)](PF6)3 exhibits several reversible single-electron redox events. The distinct electrochemical behaviors of [TREN4CuIICuICuI(μ3-OH)](PF6)3 and its solvent-exposed analog [TREN3CuIICuIICuII(μ3-O)](PF6)4 suggest that isolation of tricopper core in a cryptand enables facile electron transfer, allowing potential application of synthetic tricopper complexes as redox catalysts. Indeed, the fully reduced [TREN4CuICuICuI(μ3-OH)](PF6)2 can reduce O2 under acidic conditions. The geometric constraints provided by the cryptand are reminiscent of Nature's multicopper oxidases (MCOs). For the first time, a synthetic tricopper cluster was isolated and fully characterized at CuICuICuI (4a), CuIICuICuI (4b), and CuIICuIICuI (4c) states, providing structural and spectroscopic models for many intermediates in MCOs. Fast electron transfer rates (105 to 106 M-1 s-1) were observed for both CuICuICuI/CuIICuICuI and CuIICuICuI/CuIICuIICuI redox couples, approaching the rapid electron transfer rates of copper sites in MCO.
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Affiliation(s)
- Weiyao Zhang
- Department of Chemistry and Biochemistry, The Ohio State University 100 W. 18th Ave Columbus OH USA
| | - Curtis E Moore
- Department of Chemistry and Biochemistry, The Ohio State University 100 W. 18th Ave Columbus OH USA
| | - Shiyu Zhang
- Department of Chemistry and Biochemistry, The Ohio State University 100 W. 18th Ave Columbus OH USA
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