Mo-S Bonds Research Articles

Ab initio studies on the electronic structure of the complexes containing Mo-S bond using relativistic effective core potentials

An ab initio calculation was performed on the electronic structures of MoS, MoS2-4 and Mo2S2 using relativistic effective core potential (RECP) for molybdenum, and non-relativistic ECP for sulfur. We predicted that the equilibrium bond length and the dissociation energy of MoS in ground state are 3.89 a.u. and 4.67 eV, respectively, and that the bond is a triple-bond. The ground state of MoS2-4 in Td symmetry is 1A1 and π-bonding dominates σ-donation in the molybdenum-sulfur interaction. The Mo2S2 is a model contracted from bi-nuclear sulfur-bridged clusters, and the bonding orbitals 1b1u, 1b1g and 1b2g make the dominant contribution to the stabilization of sulfur-bridged species.

Study of a molybdenum dithiocarboxylato complex. Chemical characterization, crystal and molecular structure of tetrakis(?-dithionaphthoato)molybdenum(IV)

The complex Mo(α-C10H7CS2)4 has been prepared from several starting materials: [Mo(NNHPh)2(butane-2,3-diolate)2] · H2NNHPh, [MoCl(NNMe2)2(PPh3)2]+Cl−, [MoO2 (MeCHOCHOHMe)2] · 2MeCHOHCHOHMe or [(C4H9)4N]6Mo7O24, reacted withα-C10H7CS2H. The complex Mo(α-C10H7CS2)4 crystallizes from CH2Cl2-Et2O in the orthorhombic space group Pbca,a=13.655(3)A,b=21.707(5)A,c= 26.365(2)A, V=7814.81A3, Z=8; 5075 reflections collected, 2723 used in solution to give R=0.0517, Rw=0.0564. The molybdenum is eight coordinate with geometry approximating to aD2d dodecahedron. The average Mo-S bond lengths are 2.526(3)A and 2.479(3)A for the dodecahedrala andb sites, respectively.

Formate dehydrogenase molybdenum and tungsten sites—observation by EXAFS of structural differences

Preliminary EXAFS data has been collected on the molybdennum ( K-edge) in C. pasteurianum formate dehydrogenase and the tungsten ( L III-edge) in C. thermoaceticum formate dehydrogenase. In the presence of dithionite, the tungsten enzyme was devoid of W = O bonds, and exhibited average W-(O, N) and W-S bond lengths of 2.13 ± 0.03 Å and 2.39 ± 0.03 Å, respectively. In sharp contrast, the C. pasteurianum molybdenum site has three Mo = O bonds with an average bond lengths of 1.74 ± 0.03 Å. It is also the first molybdenum enzyme found lacking Mo-S bonds, and does not appear to be redox active in the presence of formate or dithionite. Model compounds WO 2(8-hydroxyquinoline) 2 = WO 2(ox) 2, and WO 2(8 mercaptoquinoline) 2 = WO 2(tox) 2, were also examined. Respective predicted bond lengths for WO 2(ox) 2 and WO 2(tox) 2 were W = O of 1.71, 1.73 Å; W-N of 2.31,2.29 Å; W-O or W-S of 1.92 or 2.40 Å, with estimated uncertainties of ±0.03 Å.

Molybdenum EXAFS of the desulfovibrio gigas MO(2Fe-2S) protein—structural similarity to “desulfo” xanthine dehydrogenase

The molybdenum EXAFS of the Mo(2Fe-2S) protein from Desulfovibrio gigas has been examined using fluorescence detection and synchrotron radiation. In the oxidized form the molybdenum environment is found to contain two terminal oxo groups and two long (2.47 Å) Mo-S bonds. Evidence was also found for an oxygen or nitrogen donor ligand a 1.90 Å. Addition of dithionite to the oxidized enzyme results in loss of a terminal oxo group, perhaps due to protonation. In addition, a 0.1 Å contraction in the Mo-S bond lengths is observed. The behavior of both oxidized and dithionite-treated forms is similar to that observed previously with “desulfo” xanthine oxidase.

ChemInform Abstract: ELECTRONIC AND RESONANCE RAMAN SPECTROSCOPIC STUDIES ON THE TETRATHIOMOLYBDATE(VI) ION, (MOS4)2‐. DETERMINATION OF THE EXCITED‐STATE MOLECULAR GEOMETRY

The electronic absorption and resonance Raman spectra of the tetrathiomolybdate(VI) ion have been recorded at low temperatures on solid samples. The resonance Raman spectrum, excited within the contour of the lowest-energy charge-transfer absorption band (1T2â†�1A1) at ca. 470 nm, is characterized by a number of overtone and combination tone progressions, the most prominent being that in ν1(a1). A theoretical model, based on the Condon approximation and the harmonic-oscillator approximation for both the ground and excited states, is used to simulate the excitation profiles of ν1 and its first two overtones, from which it is calculated that the MoS bond length increases by 0.07 ± 0.005 A in the excited state. Additionally, we discuss the nature of excited-state Jahn–Teller effects and the bandwidths of the members of the v1ν1 progression in terms of current theoretical knowledge.

Electronic and resonance Raman spectroscopic studies on the tetrathiomolybdate(VI) ion, [MoS4]2–. Determination of the excited-state molecular geometry

The electronic absorption and resonance Raman spectra of the tetrathiomolybdate(VI) ion have been recorded at low temperatures on solid samples. The resonance Raman spectrum, excited within the contour of the lowest-energy charge-transfer absorption band (1T2â†�1A1) at ca. 470 nm, is characterized by a number of overtone and combination tone progressions, the most prominent being that in ν1(a1). A theoretical model, based on the Condon approximation and the harmonic-oscillator approximation for both the ground and excited states, is used to simulate the excitation profiles of ν1 and its first two overtones, from which it is calculated that the MoS bond length increases by 0.07 ± 0.005 A in the excited state. Additionally, we discuss the nature of excited-state Jahn–Teller effects and the bandwidths of the members of the v1ν1 progression in terms of current theoretical knowledge.

The crystal and molecular structure of tetraphenylarsonium Tetrakis(benzenethiolato)oxomolybdate(V)

Crystals of the title compound, Ph4As+ [MoO(SPh)4]-, belong to the triclinic space group Pī with cell dimensions a 12.623(8), b 14.295(7), c 14.301(9) Ǻ, α 94.43(4), β 111.43(5), γ 65.70(4)° and Z2. The structure has been refined with diffractometer data measured with Mo Kα radiation to give a conventional R factor of 0.056 for 3215 unique terms. The Mo, As, S and O atoms were refined with anisotropic temperature factors and the C atoms with isotropic factors. The square- pyrimidal [MoO(SPh)4]- anion has the Mo atom lying 0.82 Ǻ from the basal plane of the four S atoms with Mo-O 1.699(9) Ǻ, the mean Mo-S bond lengths 2.403(5) Ǻ and the mean S...S distance 3.20(3) Ǻ. The geometry about the As atom in the Ph4As+ cation is regular tetrahedral, the mean As-C bond length being 1.91(1) Ǻ.

ChemInform Abstract: ADDUCTS OF MOLYBDENUM(V) TRICHLORIDE SULPHIDE

Chemischer InformationsdienstVolume 6, Issue 11 Organoelement Compounds ChemInform Abstract: ADDUCTS OF MOLYBDENUM(V) TRICHLORIDE SULPHIDE DAVID BRITNELL, DAVID BRITNELLSearch for more papers by this authorGERALD W. A. FOWLES, GERALD W. A. FOWLESSearch for more papers by this authorDAVID A. RICE, DAVID A. RICESearch for more papers by this author DAVID BRITNELL, DAVID BRITNELLSearch for more papers by this authorGERALD W. A. FOWLES, GERALD W. A. FOWLESSearch for more papers by this authorDAVID A. RICE, DAVID A. RICESearch for more papers by this author First published: March 18, 1975 https://doi.org/10.1002/chin.197511407AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume6, Issue11March 18, 1975 RelatedInformation

Adducts of molybdenum(V) trichloride sulphide

The compound MoCl3S reacts with methyl cyanide to give MoCl3S,MeCN and MoCl3S,2MeCN, which have been characterised as containing six-co-ordinate molybdenum with bridging Mo–S–Mo and terminal MoS bonds respectively. The complex MoCl3S,2MeCN reacts with other ligands; 1,4-dioxan and 1,2-bis(methoxy)-ethane give adducts MoCl3S,2diox and MoCl3S,bme, while pyridine gives the salt [Hpy][MoCl4S,py] and 1,10-phenanthroline reduces molybdenum to the quadrivalent state in forming MoCl2S,phen. Direct reaction of MoCl3S with py gives MoCl3S,3py (one py being in the lattice). The salts WCl3S and MoCl3S did not react with any of the ligands tried even after prolonged reaction periods.