Kinetics of the formation and hydrolysis reactions of some thiomolybdate(VI) anions in aqueous solution

Clarke, Nicholas J.; Laurie, Stuart H.; Blandamer, M. J.; Burgess, John; Hakin, Andrew W.

doi:10.1016/s0020-1693(00)85933-2

Cited by 17 publications

(17 citation statements)

References 9 publications

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“…Two important results with regard to TTM formation and existence in biological systems are that its complete formation in aqueous media requires a high S:Mo ratio and that its known increasing hydrolysis rate with increasing H ϩ concentration proceeds without detectable formation of the intermediate oxythio ions in the above scheme. [8] Earlier claims that, like MoO 4 2Ϫ , polymerisation of TTM occurs in lower pH solutions have not been substantiated. However, treatment with polysulfide produces dimeric and trimeric species in which the Mo centres have been reduced to oxidation states V and IV respectively, [ 6 ].…”

Section: Methodsmentioning

confidence: 98%

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Thiomolybdates — Simple but Very Versatile Reagents

Laurie

2000

Eur. J. Inorg. Chem.

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A large number of thiometallate anions, MOxS4−xn−, and some of the seleno analogues, are known in which M is a transition metal in a high oxidation state. They are characterised by their strong colours arising from low energy S(Se)→M charge transfer transitions, by unusual redox properties and by their ability to act as ligands to produce a wide range of heterometal complexes. This review outlines some of these properties associated with the thiometallate anions of molybdenum(VI). These anions are prepared by passing H2S through an alkaline molybdate solution, giving a sequential replacement of O atoms by S and ultimately MoS42− (TTM) as product. The thiomolybdates, particularly TTM, have been the most intensively studied because of their ease of preparation, their relatively greater thermal and hydrolytic stabilities and their biological roles. Unusual redox changes which involve internal electron transfer have been shown by reaction with organic disulfides and with CuII. In the latter case insoluble polymeric products are readily formed which, from EPR and EXAFS studies, involve S‐bridged reduced Cu and Mo centres. Reaction of TTM with CuI, on the other hand, produces a range of complexes in which from 1 to 6 Cu ions add across the tetrahedral faces of TTM with no redox changes. Further CuI ions can be added to the [Cu6(MoS4)] moiety to produce cluster ions. This illustrates the ability of the thiometallates to act as building blocks for a very wide range of heterometal complexes ranging from simple linear ions to complex clusters, a prime example of the latter being the FeMo cofactor of the enzyme nitrogenase. TTM was identified sometime ago as the reactive intermediate in the Mo‐induced Cu‐deficiency that afflicts ruminants with serious consequences. Subsequently TTM, as its ammonium salt, has been successfully used in removing the excess Cu and then controlling the Cu levels of patients of Wilson’s disease. It appears to act by blocking the intestinal absorption of Cu and by converting Cu into a metabolically inert form, and in these respects is different to the mode of action of chelating agents which can be used for treating this disease.

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Section: Methodsmentioning

confidence: 98%

“…These spectral details are given in Table 2. The distinctive UV/Vis spectra of TTM and the oxythiomolybdate anions ( Figure 1) have been used [8] to determine the rate constants for the formation (pseudo-first order with S 2Ϫ in excess) and hydrolysis of the ions as in Scheme 1.…”

Section: Preparation and Properties Of The Thiomolybdatesmentioning

confidence: 99%

Thiomolybdates — Simple but Very Versatile Reagents

Laurie

2000

Eur. J. Inorg. Chem.

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“…Although the hydrolysis of tetrathiometalates has been studied previously, this report examines the effects of changes in the metal ion, pH, and cation [77][78][79][80]. The absorption of MoS 2À 4 was followed at 469 nm and the absorption of WS 2À 4 was followed at 394 nm.…”

Section: Hydrolytic Stabilitymentioning

confidence: 99%

Reversible precipitation of bovine serum albumin by metal ions and synthesis, structure and reactivity of new tetrathiometallate chelating agents

Lee

Schulman

Stiefel

et al. 2007

Journal of Inorganic Biochemistry

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“…The preparation of Mo(VI) thiometalates proceeds via successive substitution of oxide ligands in the corresponding [MoO 4 ] 2− oxoanion 1, 10, 46, 49, 51–54. The sulfidation of molybdate to tetrathiomolybdate occurs in four successive slower steps each of which can be described as first order in both [MoO x S 4− x ] 2− ( x = 0–4) and [HS] − : …”

Section: Geometric and Energetic Reaction Profile Of The Interconversmentioning

confidence: 99%

Electronic structure calculations on multiply charged anions containing MS bonds (M = Cr, Mo, W) and their heterobimetallic cluster complexes

Gili

Tsipis

2006

Int J of Quantum Chemistry

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Molecular 2Ϫ have been investigated using electronic structure calculation (HF, MP4SDQ and DFT) methods. For the discrete mononuclear anions HF/lanl2dz(M)ഫ6-31ϩG*(S,O) method provided the best description of their molecular structures, while for the heterobimetallic dinuclear and trinuclear clusters the B3LYP/lanl2dz(M)ഫ6-31ϩG* method gave equilibrium geometries closely resembling the experimental ones. Electronic and spectroscopic (IR, UV-Vis) properties of the thiometalates are discussed in relation to their structures, while the bonding mechanism was analyzed in the framework of the natural bond orbital (NBO) approach. The nature of the highest occupied molecular orbitals (HOMOs) of all thiometalates indicated their ability to act as ligands coordinated with metal centers and forming clusters of higher nuclearity. The lowest-lying vertical one-electron detachment processes from the ground state of the Correspondence to: P. Gili;

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Kinetics of the formation and hydrolysis reactions of some thiomolybdate(VI) anions in aqueous solution

Cited by 17 publications

References 9 publications

Thiomolybdates — Simple but Very Versatile Reagents

Thiomolybdates — Simple but Very Versatile Reagents

Reversible precipitation of bovine serum albumin by metal ions and synthesis, structure and reactivity of new tetrathiometallate chelating agents

Electronic structure calculations on multiply charged anions containing MS bonds (M = Cr, Mo, W) and their heterobimetallic cluster complexes

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