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Frank P, Benfatto M. Symmetry Breaking in Solution-Phase [Cu(tsc) 2(H 2O) 2] 2+: Emergent Asymmetry in Cu-S Distances and in Covalence. J Phys Chem B 2021; 125:10779-10795. [PMID: 34546762 DOI: 10.1021/acs.jpcb.1c05022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structure of aqueous Cu(II)-bis-thiosemicarbazide, [Cu(tsc)2]2+, is reported following EXAFS and MXAN analyses of the copper K-edge X-ray absorption (XAS) spectrum. The rising K-edge feature at 8987.1 eV is higher energy than those of crystalline models, implying unique electronic and structural solution states. EXAFS analysis (k = 2-13 Å-1; 2 × Cu-N = 2.02 ± 0.01 Å; 2 × Cu-S = 2.27 ± 0.01 Å; Cu-Oax = 2.41 ± 0.04 Å) could not resolve 5- versus 6-coordinate models. However, MXAN fits converged to an asymmetric broken symmetry 6-coordinate model with cis-disposed TSC ligands (Cu-Oax = 2.07 and 2.54 Å; Cu-N = 1.94 Å, 1.98 Å; Cu-S = 2.20 Å, 2.41 Å). Transition dipole integral evaluation of the sulfur K-edge XAS 1s → 3p valence transition feature at 2470.7 eV yielded a Cu-S covalence of 0.66 e-, indicating Cu1.34+. The high Cu-S covalence and short Cu-S bond in aqueous [Cu(tsc)2(H2O)2]2+ again contradict the need for a protein rack to explain the unique structure of the blue copper active site. MXAN models of dissolved Cu(II) complex ions have invariably featured broken centrosymmetry. The potential energy ground state for dissolved Cu(II) evidently includes the extended solvation field, providing a target for improved physical theory. A revised solvation model for aqueous Cu(II), |[Cu(H2O)5]·14H2O|2+, is presented.
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Affiliation(s)
- Patrick Frank
- Stanford Synchrotron Radiation Lightsource, SLAC, Stanford University, Menlo Park, California 94025, United States.,Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Maurizio Benfatto
- Laboratori Nazionali di Frascati-INFN, P.O. Box 13, 00044 Frascati, Italy
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Credendino L, Sproules S. Modulating Iron Spin States with Radical Ligands: A Density Functional Theoretical Study. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.201900626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Stephen Sproules
- WestCHEM School of ChemistryUniversity of Glasgow Glasgow G12 8QQ UK
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Kusamoto T, Nishihara H. Zero-, one- and two-dimensional bis(dithiolato)metal complexes with unique physical and chemical properties. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2018.09.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Sproules S, Eagle AA, George GN, White JM, Young CG. Mononuclear Sulfido-Tungsten(V) Complexes: Completing the Tp*MEXY (M = Mo, W; E = O, S) Series. Inorg Chem 2017; 56:5189-5202. [DOI: 10.1021/acs.inorgchem.7b00331] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen Sproules
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Aston A. Eagle
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Graham N. George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Jonathan M. White
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Charles G. Young
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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Ye S, Kupper C, Meyer S, Andris E, Navrátil R, Krahe O, Mondal B, Atanasov M, Bill E, Roithová J, Meyer F, Neese F. Magnetic Circular Dichroism Evidence for an Unusual Electronic Structure of a Tetracarbene-Oxoiron(IV) Complex. J Am Chem Soc 2016; 138:14312-14325. [PMID: 27682505 DOI: 10.1021/jacs.6b07708] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In biology, high valent oxo-iron(IV) species have been shown to be pivotal intermediates for functionalization of C-H bonds in the catalytic cycles of a range of O2-activating iron enzymes. This work details an electronic-structure investigation of [FeIV(O)(LNHC)(NCMe)]2+ (LNHC = 3,9,14,20-tetraaza-1,6,12,17-tetraazoniapenta-cyclohexacosane-1(23),4,6(26),10,12(25),15,17(24),21-octaene, complex 1) using helium tagging infrared photodissociation (IRPD), absorption, and magnetic circular dichroism (MCD) spectroscopy, coupled with DFT and highly correlated wave function based multireference calculations. The IRPD spectrum of complex 1 reveals the Fe-O stretching vibration at 832 ± 3 cm-1. By analyzing the Franck-Condon progression, we can determine the same vibration occurring at 616 ± 10 cm-1 in the E(dxy → dxz,yz) excited state. Both values are similar to those measured for [FeIV(O)(TMC)(NCMe)]2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). The low-temperature MCD spectra of complex 1 exhibit three pseudo A-term signals around 12 500, 17 000, and 24 300 cm-1. We can unequivocally assign them to the ligand field transitions of dxy → dxz,yz, dxz,yz → dz2, and dxz,yz → dx2-y2, respectively, through direct calculations of MCD spectra and independent determination of the MCD C-term signs from the corresponding electron donating and accepting orbitals. In comparison with the corresponding transitions observed for [FeIV(O) (SR-TPA)(NCMe)]2+ (SR-TPA = tris(3,5-dimethyl-4-methoxypyridyl-2-methy)amine), the excitations within the (FeO)2+ core of complex 1 have similar transition energies, whereas the excitation energy for dxz,yz → dx2-y2 is significantly higher (∼12 000 cm-1 for [FeIV(O)(SR-TPA)(NCMe)]2+). Our results thus substantiate that the tetracarbene ligand (LNHC) of complex 1 does not significantly affect the bonding in the (FeO)2+ unit but strongly destabilizes the dx2-y2 orbital to eventually lift it above dz2. As a consequence, this unusual electron configuration leads to an unprecedentedly larger quintet-triplet energy separation for complex 1, which largely rules out the possibility that the H atom transfer reaction may take place on the quintet surface and hence quenches two-state reactivity. The resulting mechanistic implications are discussed.
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Affiliation(s)
- Shengfa Ye
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Claudia Kupper
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen , Tammannstr. 4, D-37077 Göttingen, Germany
| | - Steffen Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen , Tammannstr. 4, D-37077 Göttingen, Germany
| | - Erik Andris
- Department of Organic Chemistry, Faculty of Science, Charles University in Prague , Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Rafael Navrátil
- Department of Organic Chemistry, Faculty of Science, Charles University in Prague , Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Oliver Krahe
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Bhaskar Mondal
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Mihail Atanasov
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany.,Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences , 1113 Sofia, Bulgaria
| | - Eckhard Bill
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Jana Roithová
- Department of Organic Chemistry, Faculty of Science, Charles University in Prague , Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Franc Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen , Tammannstr. 4, D-37077 Göttingen, Germany
| | - Frank Neese
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
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Sanna D, Sciortino G, Ugone V, Micera G, Garribba E. Nonoxido V(IV) Complexes: Prediction of the EPR Spectrum and Electronic Structure of Simple Coordination Compounds and Amavadin. Inorg Chem 2016; 55:7373-87. [PMID: 27399275 DOI: 10.1021/acs.inorgchem.6b00409] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional theory (DFT) calculations of the (51)V hyperfine coupling (HFC) tensor A have been completed for 20 "bare" V(IV) complexes with different donor sets, electric charges, and coordination geometries. Calculations were performed with ORCA and Gaussian software, using functionals BP86, TPSS0, B1LYP, PBE0, B3LYP, B3P, B3PW, O3LYP, BHandHLYP, BHandH, and B2PLYP. Among the basis sets, 6-311g(d,p), 6-311++g(d,p), VTZ, cc-pVTZ, def2-TZVPP, and the "core properties" CP(PPP) were tested. The experimental Aiso and Ai (where i = x or z, depending on the geometry and electronic structure of V(IV) complex) were compared with the values calculated by DFT methods. The results indicated that, based on the mean absolute percentage deviation (MAPD), the best functional to predict Aiso or Ai is the double hybrid B2PLYP. With this functional and the basis set VTZ, it is possible to predict the Aiso and Az of the EPR spectrum of amavadin with deviations of -1.1% and -2.0% from the experimental values. The results allowed us to divide the spectra of nonoxido V(IV) compounds in three types-called "type 1", "type 2", and "type 3", characterized by different composition of the singly occupied molecular orbital (SOMO) and relationship between the values of Ax, Ay, and Az. For "type 1" spectra, Az ≫ Ax ≈ Ay and Az is in the range of (135-155) × 10(-4) cm(-1); for "type 2" spectra, Ax ≈ Ay ≫ Az and Ax ≈ Ay are in the range of (90-120) × 10(-4) cm(-1); and for the intermediate spectra of "type 3", Az > Ay > Ax or Ax > Ay > Az, with Az or Ax values in the range of (120-135) × 10(-4) cm(-1). The electronic structure of the V(IV) species was also discussed, and the results showed that the values of Ax or Az are correlated with the percent contribution of V-dxy orbital in the SOMO. Similarly to V(IV)O species, for amavadin the SOMO is based mainly on the V-dxy orbital, and this accounts for the large experimental value of Az (153 × 10(-4) cm(-1)).
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Affiliation(s)
- Daniele Sanna
- Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, UOS di Sassari, Trav. La Crucca 3, I-07040 Sassari, Italy
| | - Giuseppe Sciortino
- Dipartimento di Chimica e Farmacia, Università di Sassari , Via Vienna 2, I-07100 Sassari, Italy
| | - Valeria Ugone
- Dipartimento di Chimica e Farmacia, Università di Sassari , Via Vienna 2, I-07100 Sassari, Italy
| | - Giovanni Micera
- Dipartimento di Chimica e Farmacia, Università di Sassari , Via Vienna 2, I-07100 Sassari, Italy
| | - Eugenio Garribba
- Dipartimento di Chimica e Farmacia, Università di Sassari , Via Vienna 2, I-07100 Sassari, Italy
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Skara G, Gimferrer M, De Proft F, Salvador P, Pinter B. Scrutinizing the Noninnocence of Quinone Ligands in Ruthenium Complexes: Insights from Structural, Electronic, Energy, and Effective Oxidation State Analyses. Inorg Chem 2016; 55:2185-99. [DOI: 10.1021/acs.inorgchem.5b02543] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Gabriella Skara
- Eenheid Algemene Chemie (ALGC), Member
of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Marti Gimferrer
- Institut de Química
Computacional i Catàlisi (IQCC) i Department de Química, Universitat de Girona, 17071 Girona, Spain
| | - Frank De Proft
- Eenheid Algemene Chemie (ALGC), Member
of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Pedro Salvador
- Institut de Química
Computacional i Catàlisi (IQCC) i Department de Química, Universitat de Girona, 17071 Girona, Spain
| | - Balazs Pinter
- Eenheid Algemene Chemie (ALGC), Member
of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
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8
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Structure and magnetic properties of Saturn-shaped fullerenol complexes with ferrocene and nickelocene dicarboxylic acids: DFT simulation. Struct Chem 2015. [DOI: 10.1007/s11224-015-0718-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Bühl M, Reimann C, Pantazis DA, Bredow T, Neese F. Geometries of Third-Row Transition-Metal Complexes from Density-Functional Theory. J Chem Theory Comput 2015; 4:1449-59. [PMID: 26621431 DOI: 10.1021/ct800172j] [Citation(s) in RCA: 358] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A set of 41 metal-ligand bond distances in 25 third-row transition-metal complexes, for which precise structural data are known in the gas phase, is used to assess optimized and zero-point averaged geometries obtained from DFT computations with various exchange-correlation functionals and basis sets. For a given functional (except LSDA) Stuttgart-type quasi-relativistic effective core potentials and an all-electron scalar relativistic approach (ZORA) tend to produce very similar geometries. In contrast to the lighter congeners, LSDA affords reasonably accurate geometries of 5d-metal complexes, as it is among the functionals with the lowest mean and standard deviations from experiment. For this set the ranking of some other popular density functionals, ordered according to decreasing standard deviation, is BLYP > VSXC > BP86 ≈ BPW91 ≈ TPSS ≈ B3LYP ≈ PBE > TPSSh > B3PW91 ≈ B3P86 ≈ PBE hybrid. In this case hybrid functionals are superior to their nonhybrid variants. In addition, we have reinvestigated the previous test sets for 3d- (Bühl M.; Kabrede, H. J. Chem. Theory Comput. 2006, 2, 1282-1290) and 4d- (Waller, M. P.; Bühl, M. J. Comput. Chem. 2007, 28, 1531-1537) transition-metal complexes using all-electron scalar relativistic DFT calculations in addition to the published nonrelativistic and ECP results. For this combined test set comprising first-, second-, and third-row metal complexes, B3P86 and PBE hybrid are indicated to perform best. A remarkably consistent standard deviation of around 2 pm in metal-ligand bond distances is achieved over the entire set of d-block elements.
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Affiliation(s)
- Michael Bühl
- School of Chemistry, North Haugh, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K., and Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
| | - Christoph Reimann
- School of Chemistry, North Haugh, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K., and Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
| | - Dimitrios A Pantazis
- School of Chemistry, North Haugh, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K., and Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
| | - Thomas Bredow
- School of Chemistry, North Haugh, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K., and Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
| | - Frank Neese
- School of Chemistry, North Haugh, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K., and Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
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Skara G, Pinter B, Geerlings P, De Proft F. Revealing the thermodynamic driving force for ligand-based reductions in quinoids; conceptual rules for designing redox active and non-innocent ligands. Chem Sci 2015; 6:4109-4117. [PMID: 29218177 PMCID: PMC5707504 DOI: 10.1039/c5sc01140j] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/30/2015] [Indexed: 12/18/2022] Open
Abstract
Metal and ligand-based reductions have been modeled in octahedral ruthenium complexes revealing metal-ligand interactions as the profound driving force for the redox-active behaviour of orthoquinoid-type ligands. Through an extensive investigation of redox-active ligands we revealed the most critical factors that facilitate or suppress redox-activity of ligands in metal complexes, from which basic rules for designing non-innocent/redox-active ligands can be put forward. These rules also allow rational redox-leveling, i.e. the moderation of redox potentials of ligand-centred electron transfer processes, potentially leading to catalysts with low overpotential in multielectron activation processes.
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Affiliation(s)
- G Skara
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2 , 1050 , Brussels , Belgium .
| | - B Pinter
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2 , 1050 , Brussels , Belgium .
| | - P Geerlings
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2 , 1050 , Brussels , Belgium .
| | - F De Proft
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2 , 1050 , Brussels , Belgium .
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Ye S, Xue G, Krivokapic I, Petrenko T, Bill E, Que Jr L, Neese F. Magnetic circular dichroism and computational study of mononuclear and dinuclear iron(IV) complexes. Chem Sci 2015; 6:2909-2921. [PMID: 26417426 PMCID: PMC4583211 DOI: 10.1039/c4sc03268c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/26/2015] [Indexed: 12/13/2022] Open
Abstract
High-valent iron(IV)-oxo species are key intermediates in the catalytic cycles of a range of O2-activating iron enzymes. This work presents a detailed study of the electronic structures of mononuclear ([FeIV(O)(L)(NCMe)]2+, 1, L = tris(3,5-dimethyl-4-methoxylpyridyl-2-methyl)amine) and dinuclear ([(L)FeIV(O)(μ-O)FeIV(OH)(L)]3+, 2) iron(IV) complexes using absorption (ABS), magnetic circular dichroism (MCD) spectroscopy and wave-function-based quantum chemical calculations. For complex 1, the experimental MCD spectra at 2-10 K are dominated by a broad positive C-term band between 12000 and 18000 cm-1. As the temperature increases up to ~20 K, this feature is gradually replaced by a derivative-shaped signal. The computed MCD spectra are in excellent agreement with experiment, which reproduce not only the excitation energies and the MCD signs of key transitions but also their temperature-dependent intensity variations. To further corroborate the assignments suggested by the calculations, the individual MCD sign for each transition is independently determined from the corresponding electron donating and accepting orbitals. Thus, unambiguous assignments can be made for the observed transitions in 1. The ABS/MCD data of complex 2 exhibit ten features that are assigned as ligand-field transitions or oxo- or hydroxo-to-metal charge transfer bands, based on MCD/ABS intensity ratios, calculated excitation energies, polarizations, and MCD signs. In comparison with complex 1, the electronic structure of the FeIV=O site is not significantly perturbed by the binding to another iron(IV) center. This may explain the experimental finding that complexes 1 and 2 have similar reactivities toward C-H bond activation and O-atom transfer.
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Affiliation(s)
- Shengfa Ye
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Genqiang Xue
- Department of Chemistry , Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , USA .
| | - Itana Krivokapic
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Taras Petrenko
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Eckhard Bill
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Lawrence Que Jr
- Department of Chemistry , Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , USA .
| | - Frank Neese
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
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Kozhukh J, Minier MA, Lippard SJ. Synthesis and characterization of mononuclear, pseudotetrahedral cobalt(III) compounds. Inorg Chem 2015; 54:418-24. [PMID: 25531129 PMCID: PMC4303325 DOI: 10.1021/ic5009279] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Indexed: 11/30/2022]
Abstract
The preparation and characterization of two mononuclear cobalt(III) tropocoronand complexes, [Co(TC-5,5)](BF4) and [Co(TC-6,6)](BPh4), are reported. The cobalt(III) centers exist in rare pseudotetrahedral conformations, with twist angles of 65° and 74° for the [Co(TC-5,5](+) and [Co(TC-6,6)](+) species, respectively. Structural and electrochemical characteristics are compared with those of newly synthesized [Ga(TC-5,5)](GaCl4) and [Ga(TC-6,6)](GaCl4) analogues. The spin state of the pseudotetrahedral [Co(TC-6,6)](BPh4) compound was determined to be S = 2, a change in spin state from the value of S = 1 that occurs in the square-planar and distorted square-planar complexes, [Co(TC-3,3)](X) (X = BPh4, BAr'4) and [Co(TC-4,4)](BPh4), respectively.
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Affiliation(s)
- Julia Kozhukh
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Mikael A. Minier
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Mitra J, Sarkar S. Oxo-Mo(IV)(dithiolene)thiolato complexes: analogue of reduced sulfite oxidase. Inorg Chem 2013; 52:3032-42. [PMID: 23461669 DOI: 10.1021/ic302485c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A series of [Mo(IV)O(mnt)(SR)(N-N)](-) (mnt = maleonitriledithiolate; R = Ph, nap, p-Cl-Ph, p-CO2H-Ph, and p-NO2-Ph; N-N = 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen)) complexes analogous to the reduced active site of enzymes of the sulfite oxidase family has been synthesized and their participation in electron transfer reactions studied. Equatorial thiolate and dithiolene ligations have been used to closely simulate the three sulfur coordinations present in the native molybdenum active site. These synthetic analogues have been shown to participate in electron transfer via a pentavalent EPR-active Mo(V) intermediate with minimal structural change as observed electrochemically by reversible oxidative responses. The role of the redox-active dithiolene ligand as an electron transfer gate between external oxidants and the molybdenum center could be envisaged in one of the analogue systems where the initial transient EPR signal with <g> = 2.008 is replaced by the appearance of a typical Mo(V)-centered EPR (<g> = 1.976) signal. The appearance of such a ligand-based transient radical at the initial stage has been supported by the ligand-centered frontier orbital from DFT calculation. A stepwise rationale has been provided by computational study to show that the coupled effects of the diimine bite angle and the thiolato dihedral angle determine the metal- or ligand-based frontier orbital occupancy. DFT calculation has further supported the similarity between the reduced, semireduced, and oxidized resting state of the molybdenum center in Moco of SO with the synthesized complexes and their corresponding one-electron and fully oxidized species.
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Affiliation(s)
- Joyee Mitra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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Volpe EC, Wolczanski PT, Darmon JM, Lobkovsky EB. Syntheses and characterizations of α-iminopyridine compounds (alkylNCHpy)2Fe(L/Xn), and an assessment of redox non-innocence. Polyhedron 2013. [DOI: 10.1016/j.poly.2012.08.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Williams VA, Hulley EB, Wolczanski PT, Lancaster KM, Lobkovsky EB. Exploring the limits of redox non-innocence: pseudo square planar [{κ4-Me2C(CH2NCHpy)2}Ni]n (n = 2+, 1+, 0, −1, −2) favor Ni(ii). Chem Sci 2013. [DOI: 10.1039/c3sc50743b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Scarborough CC, Lancaster KM, DeBeer S, Weyhermüller T, Sproules S, Wieghardt K. Experimental Fingerprints for Redox-Active Terpyridine in [Cr(tpy)2](PF6)n (n = 3–0), and the Remarkable Electronic Structure of [Cr(tpy)2]1–. Inorg Chem 2012; 51:3718-32. [DOI: 10.1021/ic2027219] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Christopher C. Scarborough
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta Georgia
30322, United States
| | - Kyle M. Lancaster
- Department
of Chemistry and Chemical
Biology, Cornell University, Ithaca, New
York 14853, United States
| | - 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
| | - Thomas Weyhermüller
- 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
- EPSRC National UK EPR Facility
and Service, Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, United
Kingdom
| | - Karl Wieghardt
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36,
D-45470 Mülheim an der Ruhr, Germany
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17
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García-Monforte MA, Alonso PJ, Arauzo AB, Martín A, Menjón B, Rillo C. A square-pyramidal organochromium(v) compound. Dalton Trans 2012; 41:1297-303. [DOI: 10.1039/c1dt11376c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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18
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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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Matz KG, Mte RP, Rothstein R, Kirk ML, Nieter Burgmayer SJ. Study of molybdenum(4+) quinoxalyldithiolenes as models for the noninnocent pyranopterin in the molybdenum cofactor. Inorg Chem 2011; 50:9804-15. [PMID: 21894968 PMCID: PMC3268461 DOI: 10.1021/ic200783a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A model system for the molybdenum cofactor has been developed that illustrates the noninnocent behavior of an N-heterocycle appended to a dithiolene chelate on molybdenum. The pyranopterin of the molybdenum cofactor is modeled by a quinoxalyldithiolene ligand (S(2)BMOQO) formed from the reaction of molybdenum tetrasulfide and quinoxalylalkyne. The resulting complexes TEA[Tp*MoX(S(2)BMOQO)] [1, X = S; 3, X = O; TEA = tetraethylammonium; Tp* = hydrotris(3,5-dimethylpyrazolyl)borate] undergo a dehydration-driven intramolecular cyclization within quinoxalyldithiolene, forming Tp*MoX(pyrrolo-S(2)BMOQO) (2, X = S; 4, X = O). 4 can be oxidized by one electron to produce the molybdenum(5+) complex 5. In a preliminary report of this work, evidence from X-ray crystallography, electronic absorption and resonance Raman spectroscopies, and density functional theory (DFT) bonding calculations revealed that 4 possesses an unusual asymmetric dithiolene chelate with significant thione-thiolate character. The results described here provide a detailed description of the reaction conditions that lead to the formation of 4. Data from cyclic voltammetry, additional DFT calculations, and several spectroscopic methods (IR, electronic absorption, resonance Raman, and electron paramagnetic resonance) have been used to characterize the properties of members in this suite of five Mo(S(2)BMOQO) complexes and further substantiate the highly electron-withdrawing character of the pyrrolo-S(2)BMOQO ligand in 2, 4, and 5. This study of the unique noninnocent ligand S(2)BMOQO provides examples of the roles that the N-heterocycle pterin can play as an essential part of the molybdenum cofactor. The versatile nature of a dithiolene appended by heterocycles may aid in modulating the redox processes of the molybdenum center during the course of enzyme catalysis.
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Affiliation(s)
- Kelly G. Matz
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010
| | - Regina P. Mte
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131-0001
| | - Rebecca Rothstein
- Department of Chemistry, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131-0001
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20
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Joy S, Krämer T, Paul ND, Banerjee P, McGrady JE, Goswami S. Isolation and Assessment of the Molecular and Electronic Structures of Azo-Anion-Radical Complexes of Chromium and Molybdenum. Experimental and Theoretical Characterization of Complete Electron-Transfer Series. Inorg Chem 2011; 50:9993-10004. [DOI: 10.1021/ic200708c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sucheta Joy
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
| | - Tobias Krämer
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Nanda D. Paul
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
| | - Priyabrata Banerjee
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
| | - John E. McGrady
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Sreebrata Goswami
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India
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21
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Samuel PP, Horn S, Döring A, Havelius KGV, Reschke S, Leimkühler S, Haumann M, Schulzke C. A Crystallographic and Mo K-Edge XAS Study of Molybdenum Oxo Bis-, Mono-, and Non-Dithiolene Complexes - First-Sphere Coordination Geometry and Noninnocence of Ligands. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201100331] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Micera G, Garribba E. Is the spin-orbit coupling important in the prediction of the 51V hyperfine coupling constants of V(IV) O2+ species? ORCA versus Gaussian performance and biological applications. J Comput Chem 2011; 32:2822-35. [PMID: 21735449 DOI: 10.1002/jcc.21862] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 04/01/2011] [Accepted: 05/15/2011] [Indexed: 01/26/2023]
Abstract
Density functional theory calculations of the (51)V hyperfine coupling (HFC) tensor A, have been completed for eighteen V(IV)O(2+) complexes with different donor set, electric charge and coordination geometry. A tensor was calculated with ORCA software with several functionals and basis sets taking into account the spin-orbit coupling contribution. The results were compared with those obtained with Gaussian 03 software using the half-and-half functional BHandHLYP and 6-311g(d,p) basis set. The order of accuracy of the functionals in the prediction of A(iso), A(z) and dipolar term A(z,anis) is BHandHLYP > PBE0 >> B3PW > TPSSh >> B3LYP >> BP86 > VWN5 (for A(iso)), BHandHLYP > PBE0 >> B3PW > TPSSh > B3LYP >> BP86 > VWN5 (for A(z)), B3LYP > PBE0 ∼ B3PW ∼ BHandHLYP >> TPSSh > BP86 ∼ VWN5 (for A(z,anis)). The good agreement in the prediction of A(z) with BHandHLYP is due to a compensation between the overestimation of A(iso) and underestimation of A(z,anis) (A(z) = A(iso) + A(z,anis)), whereas among the hybrid functionals PBE0 performs better than the other ones. BHandHLYP functional and Gaussian software are recommended when the V(IV)O(2+) species contains only V-O and/or V-N bonds, whereas PBE0 functional and ORCA software for V(IV)O(2+) complexes with one or more V-S bonds. Finally, the application of these methods to the coordination environment of V(IV)O(2+) ion in V-proteins, like vanadyl-substituted insulin, carbonic anhydrase, collagen and S-adenosylmethionine synthetase, was discussed.
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Affiliation(s)
- Giovanni Micera
- Dipartimento di Chimica e Centro Interdisciplinare per lo Sviluppo della Ricerca Biotecnologica e per lo Studio della Biodiversità della Sardegna, Università di Sassari, Via Vienna 2, I-07100 Sassari, Italy
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23
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Pérez-Pla F, Llopis E, Piles M. The different kinetic and mechanistic behaviors of molybdenum and tungsten in the reduction of tris(benzene-1,2-dithiolato)Mo(VI) and W(VI) complexes by ascorbic acid in aqueous media. INT J CHEM KINET 2011. [DOI: 10.1002/kin.20524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Irwin M, Krämer T, McGrady JE, Goicoechea JM. On the Structural and Electronic Properties of [Zn2(4,4′-bipyridine)(mes)4]n− (n = 0–2), a Homologous Series of Bimetallic Complexes Bridged by Neutral, Anionic, and Dianionic 4,4′-Bipyridine. Inorg Chem 2011; 50:5006-14. [DOI: 10.1021/ic200241d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark Irwin
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Tobias Krämer
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - John E. McGrady
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Jose M. Goicoechea
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
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25
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Mangiameli MF, González JC, García SI, Frascaroli MI, Van Doorslaer S, Salas Peregrin JM, Sala LF. New insights on the mechanism of oxidation of d-galacturonic acid by hypervalent chromium. Dalton Trans 2011; 40:7033-45. [DOI: 10.1039/c1dt10214a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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26
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Sala LF, González JC, García SI, Frascaroli MI, Van Doorslaer S. Detection and structural characterization of oxo-chromium(V)-sugar complexes by electron paramagnetic resonance. Adv Carbohydr Chem Biochem 2011; 66:69-120. [PMID: 22123188 DOI: 10.1016/b978-0-12-385518-3.00002-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This article describes the detection and characterization of oxo-Cr(V)-saccharide coordination compounds, produced during chromic oxidation of carbohydrates by Cr(VI) and Cr(V), using electron paramagnetic resonance (EPR) spectroscopy. After an introduction into the main importance of chromium (bio)chemistry, and more specifically the oxo-chromium(V)-sugar complexes, a general overview is given of the current state-of-the-art EPR techniques. The next step reviews which types of EPR spectroscopy are currently applied to oxo-Cr(V) complexes, and what information about these systems can be gained from such experiments. The advantages and pitfalls of the different approaches are discussed, and it is shown that the potential of high-field and pulsed EPR techniques is as yet still largely unexploited in the field of oxo-Cr(V) complexes. Subsequently, the discussion focuses on the analysis of oxo-Cr(V) complexes of different types of sugars and the implications of the results in terms of understanding chromium (bio)chemistry.
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Affiliation(s)
- Luis F Sala
- Departamento de Químico Física-Área Química General, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
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27
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Micera G, Garribba E. Application of DFT Methods in the Study of VIVO2+-Peptide Interactions. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000382] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Huang H, Rheingold AL, Hughes RP. Synthesis and X-ray Structure of a Diamagnetic Oxo-Bridged Trifluoromethyl−Chromium(V) Complex: Structural and Computational Comparisons between CF3 and CH3 Ligands in Two Different Oxidation States of Chromium. Organometallics 2010. [DOI: 10.1021/om100543t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hui Huang
- Departments of Chemistry, 6128 Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, and University of California, San Diego, California 92093-0358
| | - Arnold L. Rheingold
- Departments of Chemistry, 6128 Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, and University of California, San Diego, California 92093-0358
| | - Russell P. Hughes
- Departments of Chemistry, 6128 Burke Laboratory, Dartmouth College, Hanover, New Hampshire 03755, and University of California, San Diego, California 92093-0358
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29
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30
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Irwin M, Jenkins RK, Denning MS, Krämer T, Grandjean F, Long GJ, Herchel R, McGrady JE, Goicoechea JM. Experimental and Computational Study of the Structural and Electronic Properties of FeII(2,2′-bipyridine)(mes)2 and [FeII(2,2′-bipyridine)(mes)2]−, a Complex Containing a 2,2′-Bipyridyl Radical Anion. Inorg Chem 2010; 49:6160-71. [DOI: 10.1021/ic100817s] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark Irwin
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Rhiannon K. Jenkins
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Mark S. Denning
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Tobias Krämer
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Fernande Grandjean
- Department of Physics, B5, University of Liège, B-4000, Sart-Tilman, Belgium
| | - Gary J. Long
- Department of Chemistry, Missouri University of Science and Technology, University of Missouri, Rolla, Missouri 65409-0010
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, tr. 17. Listopadu 12, 77146 Olomouc, Czech Republic
| | - John E. McGrady
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Jose M. Goicoechea
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
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31
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Sproules S, Benedito FL, Bill E, Weyhermüller T, DeBeer George S, Wieghardt K. Characterization and electronic structures of five members of the electron transfer series [Re(benzene-1,2-dithiolato)3](z) (z = 1+, 0, 1-, 2-, 3-): a spectroscopic and density functional theoretical study. Inorg Chem 2010; 48:10926-41. [PMID: 19831363 DOI: 10.1021/ic9010532] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of ReCl(5) with 3 equiv of a benzene-1,2-dithiolate derivative in CH(3)CN produced, after the addition of [C(8)H(16)N]Br ([C(8)H(16)N](+) is 5-azonia-spiro[4,4]nonane), brownish-green crystals of [C(8)H(16)N][Re(tms)(3)] (1c) and [C(8)H(16)N][Re(Cl(2)-bdt)(3)] (2c), where (tms)(2-) represents 3,6-bis(trimethylsilyl)benzene-1,2-dithiolate and (Cl(2)-bdt)(2-) is 3,6-dichlorobenzene-1,2-dithiolate. Chemical reduction of [Re(bdt)(3)] (3b) with n-butyllithium in the presence of PPh(4)Br yielded [PPh(4)][Re(bdt)(3)] (3c), where (bdt)(2-) is benzene-1,2-dithiolate. The three monoanionic complexes possess a diamagnetic ground state (Re(V), d(2), S = 0). The crystal structures of 1c x 2 CH(3)CN and 2c x C(3)H(6)O have been determined by X-ray crystallography. The electrochemistry establishes that the complexes are members of electron transfer series involving a monocation [Re(V)(L(*))(2)(L)](+) (S = 0(?)), a neutral [Re(V)(L(*))(L)(2)](0) (S = 1/2), a monoanion [Re(V)(L)(3)](1-) (S = 0), a dianion [Re(IV)(L)(3)](2-) (S = 1/2), and a trianion [Re(III)(L)(3)](3-) (S = 1(?)). The unique X-band EPR spectrum of the neutral species clearly describes a diamagnetic Re(V) d(2) central ion with the unpaired electron located in a purely ligand-centered molecular orbital, whereas it is metal-centered in the dianionic form: a Re(IV) d(3) ion with three dithiolate(2-) ligands. S K-edge and Re L-edge X-ray absorption spectroscopy confirms these assignments and furthermore shows that the monoanion has a Re(V) central ion with three dianionic ligands. The geometrical and electronic structures of all members of the electron transfer series have been calculated by density functional theoretical methods, and the S K-pre-edge spectra have been simulated and assigned using a time-dependent DFT protocol.
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Affiliation(s)
- Stephen Sproules
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
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32
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Milsmann C, Patra GK, Bill E, Weyhermüller T, DeBeer George S, Wieghardt K. Octahedral monodithiolene complexes of iron: characterization of S,S'-coordinated dithiolate(1-) pi radical monoanions: a spectroscopic and density functional theoretical investigation. Inorg Chem 2009; 48:7430-45. [PMID: 19572498 DOI: 10.1021/ic900936p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of cis-[Fe(III)(cyclam)Cl(2)]Cl with 1 equiv of sodium N-diethyldithiocarbamate, toluene-3,4-dithiolate, and maleonitriledithiolate in methanol in the presence of triethylamine afforded the cations [Fe(III)(cyclam)(Et(2)dtc)](2+) (1), [Fe(III)(cyclam)(tdt)](+) (2), and [Fe(III)(cyclam)(mnt)](+) (3), which were isolated as triflate, hexafluorophosphate, and tetrafluoroborate salt, respectively, using sodium triflate, potassium hexafluorophosphate, or sodium tetrafluoroborate as the source for the counteranion. Complexes 1, 2, and 3 possess an S = (1)/(2) ground state (low-spin ferric d(5)). These salts were characterized by X-ray crystallography, UV-vis, Mössbauer, and electron paramagnetic resonance spectroscopies. Cyclic voltammetry revealed that 2 and 3 are reversibly one-electron-reduced, generating neutral 2(red) and 3(red), respectively, and one-electron-oxidized, generating dicationic 2(ox) and 3(ox), respectively. Fe and S K-edge X-ray absorption spectroscopy (XAS) revealed that 2 (S = (1)/(2)) and 2(ox) (S = 0) possess a low-spin ferric ion. Complexes 2 and 3 are S,S'-coordinated to a closed-shell dithiolate(2-) ligand, whereas 2(ox) and 3(ox) consist of a low-spin ferric ion antiferromagnetically coupled to a dithiolate(1-) pi radical ligand. They are singlet diradicals [Fe(III)(cyclam)(dithiolate(*))](2+). The analysis of the sulfur K pre-edge transitions reveals significant multiplet effects in the spectra of 2 and 2(ox), which provide rare experimental evidence for a singlet diradical description for 2(ox). Mössbauer spectroscopy on frozen solutions of 2(red) clearly show the presence of a high-spin ferrous ion (S = 2). The experimentally established electronic structures of the three members of the electron transfer series [Fe(cyclam)(dithiolate)](2+,+,0) have been verified by broken symmetry density functional theoretical calculations, which have been calibrated against the experiment by calculating XAS and Mössbauer spectra.
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Affiliation(s)
- Carsten Milsmann
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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Benedito FL, Petrenko T, Bill E, Weyhermüller T, Wieghardt K. Square Planar Bis{3,6-bis(trimethylsilyl)benzene-1,2-dithiolato}metal Complexes of CrII, CoIII, and RhII: An Experimental and Density Functional Theoretical Study. Inorg Chem 2009; 48:10913-25. [DOI: 10.1021/ic9008976] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Flávio Luiz Benedito
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Taras Petrenko
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- 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
| | - Karl Wieghardt
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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34
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Banerjee P, Sproules S, Weyhermüller T, DeBeer George S, Wieghardt K. Electronic Structure of the [Tris(dithiolene)chromium]z (z = 0, 1−, 2−, 3−) Electron Transfer Series and Their Manganese(IV) Analogues. An X-ray Absorption Spectroscopic and Density Functional Theoretical Study. Inorg Chem 2009; 48:5829-47. [DOI: 10.1021/ic900154v] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Priyabrata Banerjee
- 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 George
- Stanford Synchroton Radiation Lightsource, SLAC, Stanford University, Stanford, California 94309
| | - Karl Wieghardt
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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35
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Sundararajan M, Ganyushin D, Ye S, Neese F. Multireference ab initio studies of zero-field splitting and magnetic circular dichroism spectra of tetrahedral Co(II) complexes. Dalton Trans 2009:6021-36. [PMID: 19623403 DOI: 10.1039/b902743b] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A newly developed multireference (MR) ab initio method for the calculation of magnetic circular dichroism (MCD) spectra was calibrated through the calculation of the ground- and excited state properties of seven high-spin (S = 3/2) Co(II) complexes. The MCD spectra were computed by the explicit treatment of spin-orbit coupled (SOC) and spin-spin coupled (SSC) N-electron states. For the complexes studied in this work, we found that the SOC is more important than the SSC for determining the ground state zero field splitting (ZFS). Our computed ZFS parameter D for the [Co(PPh(3))(2)Cl(2)] model complex is -17.6 cm(-1), which is reasonably close to the experimental value of -14.8 cm(-1). Generally, the computed absorption and MCD spectra are in fair agreement with experiment for all investigated complexes. Thus, reliable electronic structure and spectroscopic predictions for medium sized transition metal complexes are feasible on the basis of this methodology. This characterizes the presented method as a promising tool for MCD spectra interpretations of transition metal complexes in a variety of areas of chemistry and biology.
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Affiliation(s)
- Mahesh Sundararajan
- Institut für Physikalische und Theoretische Chemie, Wegelerstr. 12, University of Bonn, D-53115 Bonn, Germany
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Pattanayak P, Pratihar JL, Patra D, Mitra S, Bhattacharyya A, Man Lee H, Chattopadhyay S. Synthesis, structure and reactivity of azosalophen complexes of vanadium(IV): studies on cytotoxic properties. Dalton Trans 2009:6220-30. [DOI: 10.1039/b903352a] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lu CC, DeBeer George S, Weyhermüller T, Bill E, Bothe E, Wieghardt K. An electron-transfer series of high-valent chromium complexes with redox non-innocent, non-heme ligands. Angew Chem Int Ed Engl 2008; 47:6384-7. [PMID: 18618881 DOI: 10.1002/anie.200800669] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Connie C Lu
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
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Lu C, DeBeer George S, Weyhermüller T, Bill E, Bothe E, Wieghardt K. An Electron-Transfer Series of High-Valent Chromium Complexes with Redox Non-Innocent, Non-Heme Ligands. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200800669] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ganyushin D, Neese F. First-principles calculations of magnetic circular dichroism spectra. J Chem Phys 2008; 128:114117. [DOI: 10.1063/1.2894297] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Lu CC, Bill E, Weyhermüller T, Bothe E, Wieghardt K. Neutral bis(alpha-iminopyridine)metal complexes of the first-row transition ions (Cr, Mn, Fe, Co, Ni, Zn) and their monocationic analogues: mixed valency involving a redox noninnocent ligand system. J Am Chem Soc 2008; 130:3181-97. [PMID: 18284242 DOI: 10.1021/ja710663n] [Citation(s) in RCA: 235] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of bis(alpha-iminopyridine)metal complexes featuring the first-row transition ions (Cr, Mn, Fe, Co, Ni, and Zn) is presented. It is shown that these ligands are redox noninnocent and their paramagnetic pi radical monoanionic forms can exist in coordination complexes. Based on spectroscopic and structural characterizations, the neutral complexes are best described as possessing a divalent metal center and two monoanionic pi radicals of the alpha-iminopyridine. The neutral M(L*)2 compounds undergo ligand-centered, one-electron oxidations generating a second series, [(L(x))2M(THF)][B(ArF)4] [where L(x) represents either the neutral alpha-iminopyridine (L)0 and/or its reduced pi radical anion (L*)-]. The cationic series comprise mostly mixed-valent complexes, wherein the two ligands have formally different redox states, (L)0 and (L*)-, and the two ligands may be electronically linked by the bridging metal atom. Experimentally, the cationic Fe and Co complexes exhibit Robin-Day Class III behavior (fully delocalized), whereas the cationic Zn, Cr, and Mn complexes belong to Class I (localized) as shown by X-ray crystallography and UV-vis spectroscopy. The delocalization versus localization of the ligand radical is determined only by the nature of the metal linker. The cationic nickel complex is exceptional in this series in that it does not exhibit any ligand mixed valency. Instead, its electronic structure is consistent with two neutral ligands (L)0 and a monovalent metal center or [(L)2Ni(THF)][B(ArF)4]. Finally, an unusual spin equilibrium for Fe(II), between high spin and intermediate spin (S(Fe) = 2 <--> S(Fe) = 1), is described for the complex [(L*)(L)Fe(THF)][B(ArF)4], which consequently is characterized by the overall spin equilibrium (S(tot) = 3/2 <--> S(tot) = 1/2). The two different spin states for Fe(II) have been characterized using variable temperature X-ray crystallography, EPR spectroscopy, zero-field and applied-field Mössbauer spectroscopy, and magnetic susceptibility measurements. Complementary DFT studies of all the complexes have been performed, and the calculations support the proposed electronic structures.
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Affiliation(s)
- Connie C Lu
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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Kapre RR, Bothe E, Weyhermüller T, George SD, Muresan N, Wieghardt K. Electronic Structures of Tris(dioxolene)chromium and Tris(dithiolene)chromium Complexes of the Electron-Transfer Series [Cr(dioxolene)3]z and [Cr(dithiolene)3]z (z = 0, 1−, 2−, 3−). A Combined Experimental and Density Functional Theoretical Study. Inorg Chem 2007; 46:7827-39. [PMID: 17715917 DOI: 10.1021/ic7008607] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
From the reaction mixture of 3,6-di-tert-butylcatechol, H2[3,6L(cat)], [CrCl3(thf)3], and NEt3 in CH3CN in the presence of air, the neutral complex [CrIII(3,6L*(sq))3] (S = 0) (1) was isolated. Reduction of 1 with [Co(Cp)2] in CH2Cl2 yielded microcrystals of [Co(Cp)2][CrIII(3,6L*(sq))2(3,6L(cat))] (S = 1/2) (2) where (3,6L*(sq)(1-) is the pi-radical monoanionic o-semiquinonate of the catecholate dianion (3,6Lcat)(2-). Electrochemistry demonstrated that both species are members of the electron-transfer series [Cr(3,6LO,O)]z (z = 0, 1-, 2-, 3-). The corresponding tris(benzo-1,2-dithiolato)chromium complex [N(n-Bu)4][CrIII(3,5L*S,S)2(3,5LS,S)] (S = 1/2) (3) has also been isolated; (3,5LS,S)(2-) represents the closed-shell dianion 3,5-di-tert-butylbenzene-1,2-dithiolate(2-), and (3,5L*S,S)(1-) is its monoanionic pi radical. Complex 3 is a member of the electron-transfer series [Cr(3,5L(S,S))3]z (z = 0, 1-, 2-, 3-). It is shown by Cr K-edge and S K-edge X-ray absorption, UV-vis, and EPR spectroscopies, as well as X-ray crystallography, of 1 and 3 that the oxidation state of the central Cr ion in each member of both electron-transfer series remains the same (+III) and that all redox processes are ligand-based. These experimental results have been corroborated by broken symmetry density functional theoretical calculations by using the B3LYP functional.
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Affiliation(s)
- Ruta R Kapre
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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Ray K, Debeer George S, Solomon EI, Wieghardt K, Neese F. Description of the ground-state covalencies of the bis(dithiolato) transition-metal complexes from X-ray absorption spectroscopy and time-dependent density-functional calculations. Chemistry 2007; 13:2783-97. [PMID: 17290468 DOI: 10.1002/chem.200601425] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The electronic structures of [M(L(Bu))(2)](-) (L(Bu)=3,5-di-tert-butyl-1,2-benzenedithiol; M=Ni, Pd, Pt, Cu, Co, Au) complexes and their electrochemically generated oxidized and reduced forms have been investigated by using sulfur K-edge as well as metal K- and L-edge X-ray absorption spectroscopy. The electronic structure content of the sulfur K-edge spectra was determined through detailed comparison of experimental and theoretically calculated spectra. The calculations were based on a new simplified scheme based on quasi-relativistic time-dependent density functional theory (TD-DFT) and proved to be successful in the interpretation of the experimental data. It is shown that dithiolene ligands act as noninnocent ligands that are readily oxidized to the dithiosemiquinonate(-) forms. The extent of electron transfer strongly depends on the effective nuclear charge of the central metal, which in turn is influenced by its formal oxidation state, its position in the periodic table, and scalar relativistic effects for the heavier metals. Thus, the complexes [M(L(Bu))(2)](-) (M=Ni, Pd, Pt) and [Au(L(Bu))(2)] are best described as delocalized class III mixed-valence ligand radicals bound to low-spin d(8) central metal ions while [M(L(Bu))(2)](-) (M=Cu, Au) and [M(L(Bu))(2)](2-) (M=Ni, Pd, Pt) contain completely reduced dithiolato(2-) ligands. The case of [Co(L(Bu))(2)](-) remains ambiguous. On the methodological side, the calculation led to the new result that the transition dipole moment integral is noticeably different for S(1s)-->valence-pi versus S(1s)-->valence-sigma transitions, which is explained on the basis of the differences in radial distortion that accompany chemical bond formation. This is of importance in determining experimental covalencies for complexes with highly covalent metal-sulfur bonds from ligand K-edge absorption spectroscopy.
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Affiliation(s)
- Kallol Ray
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
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Ray K, Petrenko T, Wieghardt K, Neese F. Joint spectroscopic and theoretical investigations of transition metal complexes involving non-innocent ligands. Dalton Trans 2007:1552-66. [PMID: 17426855 DOI: 10.1039/b700096k] [Citation(s) in RCA: 268] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of transition metal complexes involving non-innocent o-dithiolene and o-phenylenediamine ligands has been characterized in detail by various spectroscopic methods like magnetic circular dichroism (MCD), absorption (abs), resonance Raman (rR), electron paramagnetic resonance (EPR), and sulfur K-edge X-ray absorption spectroscopies. A computational model for the electronic structure of the complexes is then proposed based on the density functional theory (DFT) or ab-initio methods, which can successfully account for the observed trends in the experimental spectra (MCD, rR, and abs) of the complexes. Based on these studies, the innocent vs non-innocent nature of the ligands in a given transition metal complex is found to be dependent on the position of the central metal ion in the periodic table, its effective nuclear charge in interplay with relativistic effects.
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Affiliation(s)
- Kallol Ray
- Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, D-53115 Bonn, Germany
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