The interaction of hard base chelating agents (LH) such as 8-quinolinol (oxH), salicylaldehyde (salH) and N-nitrosophenylhydroxylamine (NphaH) with ammonium tetrathiomolybdate(VI), (1), in aqueous solution yields disulphidomolybdenum(VI) complexes, [MoS2L2]. The i.r. absorptions at 540 and 510 cm-1 are assigned to v(Mo-S), which indicate that the two sulphido-groups are cis to each other, The interaction of (1) with soft base chelating agents (SS), such as dithiocarbamates (dtc), dithiophosphate (dtp) and xanthates (xan) yields dimeric sulphido-bridged sulphidomolybdenum(V) complexes, [Mo2S4(SS)2] and with potassium ethylthioxanthate (KEttxan) yields a molybdenum(IV) complex, [Mo(Ettxan)4]. The [Mo2S4(R2dtc)2] complexes were also obtained by the interaction of [MoO2(R2dtc)2] with phosphorus pentasulphide in xylene. It was concluded that tetrathiomolybdate(VI) undergoes facile reduction when compared with tetraoxomolybdate(VI). © 1986 VCH Verlagsgesellschaft mbH.

M. Ramakrishna Udupa

AMMONIUM COMPOUNDS

Biochemistry

Chemical Reactions - Redox

Potassium compounds

Salts

DITHIOCARBONATES

SOFT BASE CHELATING AGENTS

TETRATHIOMOLYBDATE(VI) ANION

Molybdenum compounds

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IIT Madras

Reactivity of the tetrathiomolybdate(VI) anion towards hard and soft base chelating agents

Transition Metal Chemistry

The interaction of H2S gas with aqueous ammonium heptamolybdate solution in the presence of diethylenetriamine (dien) led to the formation of diethylenetriammonium tetrathiomolybdate crystals. The elemental analyses, UV-Visible, IR, and 1H NMR spectra suggested the presence of organic cation and (MoS4)2- moiety. The 1H NMR revealed the presence of two sets of symmetrical A2X2 multiple patterns. The compound crystallizes in the monoclinic system with space group Pn, a = 7.196(6), b = 7.532(3), c = 11.525(10) Å, α = 90°, β = 90.17(3)°, γ = 90°, V = 624.78(8) Å3, and Z = 2, wR1 = 0.0261 and wR2 = 0.0698. The structure consists of tetrahedral tetrathiomolybdate anions, which form an extended three-dimensional network in the solid state with Mo-S⋯H-N hydrogen bonding with the organic cation.

Journal of Chemical Crystallography

Preparation, characterization, and X-ray structure analysis of diethylenetriammonium tetrathiomolybdate

The interaction of ammonium tetrathiomolybdate with the barium salts of the dithiocarbamates (dtc) of glycine, DL-alanine and DL-2-aminobutyric acid yielded Ba[Mo2S4(dtc)2]. The molar conductivities (∼ 50 Ω-1 cm-1) in DMSO indicated the ionic nature of the complexes. The subnormal magnetic moment (0.4 B.M.), electronic and IR spectral data and CVM peak potentials ( -0.95 and -1.25 V vs SCE) suggested a dimeric species with a [Mo2S4]2+ core. The IR spectral data suggested the bidentate coordination of the dithiocarbamate groups and the absence of coordination by the carboxylate group. Thermal properties of the complexes are discussed. © 1992.

Polyhedron

Sulphidomolybdenum(V) complexes with amino acid dithiocarbamates

Synthesis and characterization of four Mo(VI) complexes of a diprotic tridentate ONS chelating ligand (H2L) containing the rather elusive [MoVIOS]2+ core is reported. These [MoVIOSL] complexes are obtained from their corresponding [MoVIO2L] precursors using a combination of PPh3 and PPh3S. This process of oxo-abstraction and sulfido-inclusion affected by PPh3-PPh3S is reported for the first time and may be considered as a general method of converting [MoVIO2L] complexes to the corresponding [MoVIOSL] complexes. Direct structural characterization of these complexes could not be done due to the ease of solvolysis of these oxosulfidomolybdenum(VI) complexes to the corresponding dioxomolybdenum(VI) analogues. However, the structure of these [MoVIOSL] complexes could be reasonably surmised from the corresponding structurally characterized [MoVIO2L] complexes. Points of attachment of the potentially pentadentate but functionally tridentate ONS chelating ligands to [MoVIOS]2+ are located mainly through analysis of IR and UV-Vis spectral data and comparison with corresponding [MoVIO2L] complexes of known structure. Conditions under which solvolysis of [MoVIOS]2+ to the [MoVIO2]2+ core is significantly retarded have been identified and make us hopeful of obtaining single crystals of [MoVIOSL]. © 2009 Taylor &amp; Francis.

Journal	Transition Metal Chemistry
Publisher	Kluwer Academic Publishers
ISSN	03404285
Open Access	No