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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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2
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Reschke S, Mebs S, Sigfridsson-Clauss KGV, Kositzki R, Leimkühler S, Haumann M. Protonation and Sulfido versus Oxo Ligation Changes at the Molybdenum Cofactor in Xanthine Dehydrogenase (XDH) Variants Studied by X-ray Absorption Spectroscopy. Inorg Chem 2017; 56:2165-2176. [DOI: 10.1021/acs.inorgchem.6b02846] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Stefan Reschke
- Institut für
Biochemie und Biologie, Molekulare Enzymologie, Universität Potsdam, 14476 Potsdam, Germany
| | - Stefan Mebs
- Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Ramona Kositzki
- Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Silke Leimkühler
- Institut für
Biochemie und Biologie, Molekulare Enzymologie, Universität Potsdam, 14476 Potsdam, Germany
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany
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3
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Maia LB, Moura I, Moura JJ. EPR Spectroscopy on Mononuclear Molybdenum-Containing Enzymes. FUTURE DIRECTIONS IN METALLOPROTEIN AND METALLOENZYME RESEARCH 2017. [DOI: 10.1007/978-3-319-59100-1_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Young CG. Chemical systems modeling the d1 Mo(V) states of molybdenum enzymes. J Inorg Biochem 2016; 162:238-252. [PMID: 27432259 DOI: 10.1016/j.jinorgbio.2016.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/14/2016] [Accepted: 06/03/2016] [Indexed: 11/29/2022]
Affiliation(s)
- 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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5
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Affiliation(s)
- Charles G. Young
- Department of Chemistry and PhysicsLa Trobe Institute for Molecular ScienceLa Trobe University3086MelbourneVictoriaAustralia
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McGrath AP, Laming EL, Casas Garcia GP, Kvansakul M, Guss JM, Trewhella J, Calmes B, Bernhardt PV, Hanson GR, Kappler U, Maher MJ. Structural basis of interprotein electron transfer in bacterial sulfite oxidation. eLife 2015; 4:e09066. [PMID: 26687009 PMCID: PMC4760952 DOI: 10.7554/elife.09066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 11/12/2015] [Indexed: 11/13/2022] Open
Abstract
Interprotein electron transfer underpins the essential processes of life and relies on the formation of specific, yet transient protein-protein interactions. In biological systems, the detoxification of sulfite is catalyzed by the sulfite-oxidizing enzymes (SOEs), which interact with an electron acceptor for catalytic turnover. Here, we report the structural and functional analyses of the SOE SorT from Sinorhizobium meliloti and its cognate electron acceptor SorU. Kinetic and thermodynamic analyses of the SorT/SorU interaction show the complex is dynamic in solution, and that the proteins interact with Kd = 13.5 ± 0.8 μM. The crystal structures of the oxidized SorT and SorU, both in isolation and in complex, reveal the interface to be remarkably electrostatic, with an unusually large number of direct hydrogen bonding interactions. The assembly of the complex is accompanied by an adjustment in the structure of SorU, and conformational sampling provides a mechanism for dissociation of the SorT/SorU assembly.
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Affiliation(s)
- Aaron P McGrath
- Structural Biology Program, Centenary Institute, Sydney, Australia
| | - Elise L Laming
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - G Patricia Casas Garcia
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Marc Kvansakul
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - J Mitchell Guss
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - Jill Trewhella
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - Benoit Calmes
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Paul V Bernhardt
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Graeme R Hanson
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | - Ulrike Kappler
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Megan J Maher
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
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7
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Liu X, Xing N, Song J, Wu Q, Yan Z, Zhang Y, Xing Y. Two novel oxomolybdenum(V)-trispyrazolylborate complexes: Synthesis, structure, and catalytic performance in the cyclohexane oxidation. Polyhedron 2015. [DOI: 10.1016/j.poly.2015.09.056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Doonan CJ, Gourlay C, Nielsen DJ, Ng VWL, Smith PD, Evans DJ, George GN, White JM, Young CG. d(1) Oxosulfido-Mo(V) Compounds: First Isolation and Unambiguous Characterization of an Extended Series. Inorg Chem 2015; 54:6386-96. [PMID: 26046577 DOI: 10.1021/acs.inorgchem.5b00708] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of Tp(iPr)Mo(VI)OS(OAr) with cobaltocene in toluene results in the precipitation of brown, microcrystalline oxosulfido-Mo(V) compounds, [CoCp2][Tp(iPr)Mo(V)OS(OAr)] (Cp(-) = η(5)-C5H5(-), Tp(iPr)(-) = hydrotris(3-isopropylpyrazol-1-yl)borate, OAr(-) = phenolate or 2-(s)Bu, 2-(t)Bu, 3-(t)Bu, 4-(s)Bu, 4-Ph, 3,5-(s)Bu2, 2-CO2Me, 2-CO2Et or 2-CO2Ph derivative thereof). The compounds are air- and water-sensitive and display ν(Mo═O) and ν(Mo[Formula: see text]S) IR absorption bands at ca. 890 and 435 cm(-1), respectively, 20-40 cm(-1) lower in energy than the corresponding bands in Tp(iPr)MoOS(OAr). They are electrochemically active and exhibit three reversible cyclovoltammetric waves (E(Mo(VI)/Mo(V)) = -0.40 to -0.66 V, E([CoCp2](+)/CoCp2) = -0.94 V and E(CoCp2/[CoCp2](-)) = -1.88 V vs SCE). Structural characterization of [CoCp2][Tp(iPr)MoOS(OC6H4CO2Et-2)]·2CH2Cl2 revealed a distorted octahedral Mo(V) anion with Mo═O and Mo[Formula: see text]S distances of 1.761(5) and 2.215(2) Å, respectively, longer than corresponding distances in related Tp(iPr)MoOS(OAr) compounds. The observation of strong S(1s) → (S(3p) + Mo(4d)) S K-preedge transitions indicative of a d(1) sulfido-Mo(V) moiety and the presence of short Mo═O (ca. 1.72 Å) and Mo[Formula: see text]S (ca. 2.25 Å) backscattering contributions in the Mo K-edge EXAFS further support the oxosulfido-Mo(V) formulation. The compounds are EPR-active, exhibiting highly anisotropic (Δg 0.124-0.150), rhombic, frozen-glass spectra with g1 close to the value observed for the free electron (ge = 2.0023). Spectroscopic studies are consistent with the presence of a highly covalent Mo[Formula: see text]S π* singly occupied molecular orbital. The compounds are highly reactive, with reactions localized at the terminal sulfido ligand. For example, the compounds react with cyanide and PPh3 to produce thiocyanate and SPPh3, respectively, and various (depending on solvent) oxo-Mo(V) species. Reactions with copper reagents also generally lead to desulfurization and the formation of oxo-Mo(V) or -Mo(IV) complexes.
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Affiliation(s)
| | | | | | | | | | | | - Graham N George
- §Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | | | - 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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9
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Yang J, Giles LJ, Ruppelt C, Mendel RR, Bittner F, Kirk ML. Oxyl and hydroxyl radical transfer in mitochondrial amidoxime reducing component-catalyzed nitrite reduction. J Am Chem Soc 2015; 137:5276-9. [PMID: 25897643 PMCID: PMC4872596 DOI: 10.1021/jacs.5b01112] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of electron paramagnetic resonance (EPR) spectroscopy and computational approaches has provided insight into the nature of the reaction coordinate for the one-electron reduction of nitrite by the mitochondrial amidoxime reducing component (mARC) enzyme. The results show that a paramagnetic Mo(V) species is generated when reduced enzyme is exposed to nitrite, and an analysis of the resulting EPR hyperfine parameters confirms that mARC is remarkably similar to the low-pH form of sulfite oxidase. Two mechanisms for nitrite reduction have been considered. The first shows a modest reaction barrier of 14 kcal/mol for the formation of ·NO from unprotonated nitrite substrate. In marked contrast, protonation of the substrate oxygen proximal to Mo in the Mo(IV)-O-N-O substrate-bound species results in barrierless conversion to products. A fragment orbital analysis reveals a high degree of Mo-O(H)-N-O covalency that provides a π-orbital pathway for one-electron transfer to the substrate and defines orbital constraints on the Mo-substrate geometry for productive catalysis in mARC and other pyranopterin molybdenum enzymes that catalyze this one-electron transformation.
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Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Logan J. Giles
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Christian Ruppelt
- Department of Plant Biology, Braunschweig University of Technology, Humboldtstrasse 1, 38023 Braunschweig, Germany
| | - Ralf R. Mendel
- Department of Plant Biology, Braunschweig University of Technology, Humboldtstrasse 1, 38023 Braunschweig, Germany
| | - Florian Bittner
- Department of Plant Biology, Braunschweig University of Technology, Humboldtstrasse 1, 38023 Braunschweig, Germany
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
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Xu XJ. Synthesis, crystal structure, and thermal stability of [Mo2O4(μ2-O)(C6H4O2)2(H2O)] · (C8H9N2)2 · 2H2O. RUSS J COORD CHEM+ 2014. [DOI: 10.1134/s1070328414010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Xing N, Shan H, Tian X, Yao Q, Xu LT, Xing YH, Shi Z. Two new scorpionate oxomolybdenum(vi)–poly(pyrazolyl)borate complexes: synthesis, structure, and catalytic performance in the oxidation of cyclohexane. Dalton Trans 2013; 42:359-63. [DOI: 10.1039/c2dt32184j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Hanson GR, Noble CJ, Benson S. XSophe – Sophe – XeprView and Molecular Sophe: Computer Simulation Software Suites for the Analysis of Continuous Wave and Pulsed EPR and ENDOR Spectra. PROGRESS IN THEORETICAL CHEMISTRY AND PHYSICS 2013. [DOI: 10.1007/978-94-007-4893-4_5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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13
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Yan Y, Chandrasekaran P, Mague JT, DeBeer S, Sproules S, Donahue JP. Redox-Controlled Interconversion between Trigonal Prismatic and Octahedral Geometries in a Monodithiolene Tetracarbonyl Complex of Tungsten. Inorg Chem 2011; 51:346-61. [DOI: 10.1021/ic201748v] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yong Yan
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans,
Louisiana 70118-5698, United States
| | - Perumalreddy Chandrasekaran
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans,
Louisiana 70118-5698, United States
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Joel T. Mague
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans,
Louisiana 70118-5698, United States
| | - Serena DeBeer
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
- 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, U.K
| | - James P. Donahue
- Department of Chemistry, Tulane University, 6400 Freret Street, New Orleans,
Louisiana 70118-5698, United States
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14
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Sempombe J, Stein B, Kirk ML. Spectroscopic and electronic structure studies probing covalency contributions to C-H bond activation and transition-state stabilization in xanthine oxidase. Inorg Chem 2011; 50:10919-28. [PMID: 21972782 DOI: 10.1021/ic201477n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A detailed electron paramagnetic resonance (EPR) and computational study of a key paramagnetic form of xanthine oxidase (XO) has been performed and serves as a basis for developing a valence-bond description of C-H activation and transition-state (TS) stabilization along the reaction coordinate with aldehyde substrates. EPR spectra of aldehyde-inhibited XO have been analyzed in order to provide information regarding the relationship between the g, (95,97)Mo hyperfine (A(Mo)), and (13)C hyperfine (A(C)) tensors. Analysis of the EPR spectra has allowed for greater insight into the electronic origin of key delocalizations within the Mo-O(eq)-C fragment and how these contribute to C-H bond activation/cleavage and TS stabilization. A natural bond orbital analysis of the enzyme reaction coordinate with aldehyde substrates shows that both Mo═S π → C-H σ* (ΔE = 24.3 kcal mol(-1)) and C-H σ → Mo═S π* (ΔE = 20.0 kcal mol(-1)) back-donation are important in activating the substrate C-H bond for cleavage. Additional contributions to C-H activation derive from O(eq) lp → C-H σ* (lp = lone pair; ΔE = 8.2 kcal mol(-1)) and S lp → C-H σ* (ΔE = 13.2 kcal mol(-1)) stabilizing interactions. The O(eq)-donor ligand that derives from water is part of the Mo-O(eq)-C fragment probed in the EPR spectra of inhibited XO, and the observation of O(eq) lp → C-H σ* back-donation indicates a key role for O(eq) in activating the substrate C-H bond for cleavage. We also show that the O(eq) donor plays an even more important role in TS stabilization. We find that O(eq) → Mo + C charge transfer dominantly contributes to stabilization of the TS (ΔE = 89.5 kcal mol(-1)) and the Mo-O(eq)-C delocalization pathway reduces strong electronic repulsions that contribute to the classical TS energy barrier. The Mo-O(eq)-C delocalization at the TS allows for the TS to be described in valence-bond terms as a resonance hybrid of the reactant (R) and product (P) valence-bond wave functions.
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Affiliation(s)
- Joseph Sempombe
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, USA
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15
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Mtei RP, Lyashenko G, Stein B, Rubie N, Hille R, Kirk ML. Spectroscopic and electronic structure studies of a dimethyl sulfoxide reductase catalytic intermediate: implications for electron- and atom-transfer reactivity. J Am Chem Soc 2011; 133:9762-74. [PMID: 21648481 PMCID: PMC3142581 DOI: 10.1021/ja109178q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The electronic structure of a genuine paramagnetic des-oxo Mo(V) catalytic intermediate in the reaction of dimethyl sulfoxide reductase (DMSOR) with (CH(3))(3)NO has been probed by electron paramagnetic resonance (EPR), electronic absorption, and magnetic circular dichroism (MCD) spectroscopies. EPR spectroscopy reveals rhombic g- and A-tensors that indicate a low-symmetry geometry for this intermediate and a singly occupied molecular orbital that is dominantly metal centered. The excited-state spectroscopic data were interpreted in the context of electronic structure calculations, and this has resulted in a full assignment of the observed MCD and electronic absorption bands, a detailed understanding of the metal-ligand bonding scheme, and an evaluation of the Mo(V) coordination geometry and Mo(V)-S(dithiolene) covalency as it pertains to the stability of the intermediate and electron-transfer regeneration. Finally, the relationship between des-oxo Mo(V) and des-oxo Mo(IV) geometric and electronic structures is discussed relative to the reaction coordinate in members of the DMSOR enzyme family.
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Affiliation(s)
- Regina P Mtei
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, USA
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16
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Sugimoto H, Tano H, Suyama K, Kobayashi T, Miyake H, Itoh S, Mtei RP, Kirk ML. Chalcogenidobis(ene-1,2-dithiolate)molybdenum(IV) complexes (chalcogenide E = O, S, Se): probing Mo≡E and ene-1,2-dithiolate substituent effects on geometric and electronic structure. Dalton Trans 2011; 40:1119-31. [PMID: 21165484 PMCID: PMC3168557 DOI: 10.1039/c0dt00871k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New square-pyramidal bis(ene-1,2-dithiolate)MoSe complexes, [Mo(IV)Se(L)(2)](2-), have been synthesised along with their terminal sulfido analogues, [Mo(IV)S(L)(2)](2-), using alkyl (L(C(4)H(8))), phenyl (L(Ph)) and methyl carboxylate (L(COOMe)) substituted dithiolene ligands (L). These complexes now complete three sets of Mo(IV)O, Mo(IV)S and Mo(IV)Se species that are coordinated with identical ene-1,2-dithiolate ligands. The [alkyl substituted Mo(S/Se)(L(C(4)H(8)))(2)](2-) complexes were reported in prior investigations (H. Sugimoto, T. Sakurai, H. Miyake, K. Tanaka and H. Tsukube, Inorg. Chem. 2005, 44, 6927, H. Tano, R. Tajima, H. Miyake, S. Itoh and H. Sugimoto, Inorg. Chem. 2008, 47, 7465). The new series of complexes enable a systematic investigation of terminal chalcogenido and supporting ene-1,2-dithiolate ligand effects on geometric structure, electronic structure, and spectroscopic properties. X-ray crystallographic analysis of these (Et(4)N)(2)[MoEL(2)] (E = terminal chalocogenide) complexes reveals an isostructural Mo centre that adopts a distorted square pyramidal geometry. The M≡E bond distances observed in the crystal structures and the ν(M≡E) vibrational frequencies indicate that these bonds are weakened with an increase in L→Mo electron donation (L(COOMe) < L(Ph) < L(C(4)H(8))), and this order is confirmed by an electrochemical study of the complexes. The (77)Se NMR resonances in MoSeL complexes appear at lower magnetic fields as the selenido ion became less basic from MoSeL(C(4)H(8)), MoSeL(Ph) and MoSeL(COOMe). Electronic absorption and resonance Raman spectroscopies have been used to assign key ligand-field, MLCT, LMCT and intraligand CT bands in complexes that possess the L(COOMe) ligand. The presence of low-energy intraligand CT transition in these MoEL(COOMe) compounds directly probes the electron withdrawing nature of the -COOMe substituents, and this underscores the complex electronic structure of square pyramidal bis(ene-1,2-dithiolate)-Mo(IV) complexes that possess extended dithiolene conjugation.
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Affiliation(s)
- Hideki Sugimoto
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871Japan
| | - Hiroyuki Tano
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Koichiro Suyama
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Tomoya Kobayashi
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hiroyuki Miyake
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shinobu Itoh
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871Japan
| | - Regina P. Mtei
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131–0001, USA
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131–0001, USA
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17
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Muraoka T, Nakamura T, Nakamura A, Ueno K. Reactions of (Silyl)(silylene)tungsten and -molybdenum Complexes with Sulfur Reagents. Organometallics 2010. [DOI: 10.1021/om100875h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takako Muraoka
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, Kiryu 376-8515, Japan
| | - Tomoko Nakamura
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, Kiryu 376-8515, Japan
| | - Atsushi Nakamura
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, Kiryu 376-8515, Japan
| | - Keiji Ueno
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, Kiryu 376-8515, Japan
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18
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Reinheimer EW, Olejniczak I, Łapiński A, Swietlik R, Jeannin O, Fourmigué M. Structural distortions upon oxidation in heteroleptic [Cp(2)W(dmit)] tungsten dithiolene complex: combined structural, spectroscopic, and magnetic studies. Inorg Chem 2010; 49:9777-87. [PMID: 20882972 DOI: 10.1021/ic1006296] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Four different cation radical salts are obtained upon electrocrystallization of [Cp(2)W(dmit)] (dmit = 1,3-dithiole-2-thione-4,5-dithiolato) in the presence of the BF(4)(-), PF(6)(-), Br(-), and [Au(CN)(2)](-) anions. In these formally d(1) cations, the WS(2)C(2) metallacycle is folded along the S···S hinge to different extents in the four salts, an illustration of the noninnocent character of the dithiolate ligand. Structural characteristics and the charge distribution on atoms, for neutral and ionized complexes with various folding angles, were calculated using DFT methods, together with the normal vibrational modes and theoretical Raman spectra. Raman spectra of neutral complex [Cp(2)W(dmit)] and its salts formed with BF(4)(-), AsF(6)(-), PF(6)(-), Br(-), and [Au(CN)(2)](-) anions were measured using the red excitation (λ = 632.8 nm). A correlation between the folding angle of the metallacycle and the Raman spectroscopic properties is analyzed. The bands attributed to the C═C and C-S stretching modes shift toward higher and lower frequencies by about 0.3-0.4 cm(-1) deg(-1), respectively. The solid state structural and magnetic properties of the three salts are analyzed and compared with those of the corresponding molybdenum complexes. Temperature dependence of the magnetic susceptibility shows the presence of one-dimensional antiferromagnetic interactions in the BF(4)(-), PF(6)(-), and [Au(CN)(2)](-) salts, while an antiferromagnetic ground state is identified in the Br(-) salt below T(Néel) = 7 K. Interactions are systematically weaker in the tungsten salts than in the isostructural molybdenum analogs, a consequence of the decreased spin density on the dithiolene ligand in the tungsten complexes.
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Affiliation(s)
- Eric W Reinheimer
- Sciences Chimiques de Rennes, Université de Rennes I & CNRS UMR 6226, Campus de Beaulieu, 35042 Rennes, France
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19
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Drew SC, Baldas J, Boas JF. Theoretical Calculation of the Magnetic Resonance Parameters of Trigonal-Prismatic Tris(o-aminobenzenethiol)technetium and -rhenium Complexes. Inorg Chem 2010; 49:6799-801. [DOI: 10.1021/ic1009175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Simon C. Drew
- Max Planck Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany
| | - John Baldas
- Australian Radiation Protection and Nuclear Safety Agency, Lower Plenty Road, Yallambie, Victoria 3085, Australia
| | - John F. Boas
- Australian Radiation Protection and Nuclear Safety Agency, Lower Plenty Road, Yallambie, Victoria 3085, Australia
- School of Physics, Monash University, Victoria 3800, Australia
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20
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Yang J, Rothery R, Sempombe J, Weiner JH, Kirk ML. Spectroscopic characterization of YedY: the role of sulfur coordination in a Mo(V) sulfite oxidase family enzyme form. J Am Chem Soc 2010; 131:15612-4. [PMID: 19860477 DOI: 10.1021/ja903087k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electronic paramagnetic resonance (EPR), electronic absorption, and magnetic circular dichroism spectroscopies have been performed on YedY, a SUOX fold protein with a Mo domain that is remarkably similar to that found in chicken sulfite oxidase, Arabidopsis thaliana plant sulfite oxidase, and the bacterial sulfite dehydrogenase from Starkeya novella. Low-energy dithiolene --> Mo and cysteine thiolate --> Mo charge-transfer bands have been assigned for the first time in a Mo(V) form of a SUOX fold protein, and the spectroscopic data have been used to interpret the results of bonding calculations. The analysis shows that second coordination sphere effects modulate dithiolene and cysteine sulfur covalency contributions to the Mo bonding scheme. In particular, a more acute O(oxo)-Mo-S(Cys)-C dihedral angle results in increased cysteine thiolate S --> Mo charge transfer and a large g(1) in the EPR spectrum. The spectrosocopic results, coupled with the available structural data, indicate that these second coordination sphere effects may play key roles in modulating the active-site redox potential, facilitating hole superexchange pathways for electron transfer regeneration, and affecting the type of reactions catalyzed by sulfite oxidase family enzymes.
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Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, USA
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21
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Hanson GR, Lane I. Dimethylsulfoxide (DMSO) Reductase, a Member of the DMSO Reductase Family of Molybdenum Enzymes. METALS IN BIOLOGY 2010. [DOI: 10.1007/978-1-4419-1139-1_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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22
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A multiconfigurational perturbation theory study of the electronic structure and EPR g values of an oxomolybdenum enzyme model complex. Theor Chem Acc 2009. [DOI: 10.1007/s00214-009-0605-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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23
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Hanson GR, Noble CJ, Benson S. Molecular Sophe: An Integrated Approach to the Structural Characterization of Metalloproteins: The Next Generation of Computer Simulation Software. HIGH RESOLUTION EPR 2009. [DOI: 10.1007/978-0-387-84856-3_4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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24
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Roy S, Patra AK, Dhar S, Chakravarty AR. Photosensitizer in a Molecular Bowl and its Effect on the DNA-Binding and -Cleavage Activity of 3d-Metal Scorpionates. Inorg Chem 2008; 47:5625-33. [DOI: 10.1021/ic702508r] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Sovan Roy
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Ashis K. Patra
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Shanta Dhar
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Akhil R. Chakravarty
- Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
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25
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Young CG. Facets of early transition metal–sulfur chemistry: Metal–sulfur ligand redox, induced internal electron transfer, and the reactions of metal–sulfur complexes with alkynes. J Inorg Biochem 2007; 101:1562-85. [PMID: 17761291 DOI: 10.1016/j.jinorgbio.2007.06.040] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 06/25/2007] [Accepted: 06/26/2007] [Indexed: 10/23/2022]
Abstract
Metal-sulfur ligand redox interplay, induced internal electron transfer reactions, and the generation of dithiolene and organosulfur ligands in the reactions of metal-sulfur compounds with alkynes are important and useful facets of early transition metal-sulfur chemistry. This review focuses on developments in these areas over the past 30 years.
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Affiliation(s)
- Charles G Young
- School of Chemistry, University of Melbourne, Victoria 3010, Australia.
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26
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Drew SC, Young CG, Hanson GR. A Density Functional Study of the Electronic Structure and Spin Hamiltonian Parameters of Mononuclear Thiomolybdenyl Complexes. Inorg Chem 2007; 46:2388-97. [PMID: 17305330 DOI: 10.1021/ic060586b] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electron paramagnetic resonance spin Hamiltonian parameters of mononuclear thiomolybdenyl complexes based upon the tris(pyrazolyl)borate ligand, together with their molybdenyl analogues, are calculated using density functional theory. The electronic g matrix and 95Mo hyperfine matrix are calculated as second-order response properties from the coupled-perturbed Kohn-Sham equations. The scalar relativistic zero-order regular approximation (ZORA) is used with an all-electron basis and an accurate mean-field spin-orbit operator which includes all one- and two-electron terms. The principal values and relative orientations of the g and A interaction matrices obtained from the experimental spectra in a previous EPR study are compared with those obtained from unrestricted Kohn-Sham calculations at the BP86 and B3LYP level, and the latter are found to be in good quantitative agreement. A quasi-restricted approach is used to analyze the influence of the various molecular orbitals on g and A. In all complexes the ground state magnetic orbital is dX2-Y2-based and the orientation of the A matrix is directly related to the orientation of this orbital. The largest single contribution to the orientation of the g matrix arises from the spin-orbit coupling of the dYZ-based lowest-unoccupied molecular orbital into the ground state. A number of smaller, cumulative charge-transfer contributions augment the d-d contributions. A comparison of the theoretical EPR parameters obtained using both crystallographic and gas-phase geometry-optimized structures of Tp*MoO(bdt) (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate, bdt = 1,2-benzenedithiolate) suggests a correspondence between the metal-dithiolate fold angle and the angle of noncoincidence between g and A.
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Affiliation(s)
- Simon C Drew
- Centres for Magnetic Resonance and Metals in Biology, University of Queensland, Queensland 4072, Australia.
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