A Family of Oxo-Chalcogenide Molybdenum and Tungsten Complexes, (n-Bu₄N)₂[M₂O₂(μ-Q)₂(1,3-dithiole-2-thione-4,5-dithiolate)₂] (M = Mo, W; Q = S, Se):  New Synthetic Entries, Structure, and Gas-Phase Behavior

Abstract

A new series of complexes with the general formula (n-Bu4N)2[M2O2(micro-Q)2(dmit)2] (where M = Mo, W; Q = S, Se; dmit = 1,3-dithiole-2-thione-4,5-dithiolate) have been prepared. Fragmentation of the trinuclear cluster (n-Bu4N)2[Mo3(micro3-S)(micro-S2)3(dmit)3] in the presence of triphenylphosphine (PPh3) gives the dinuclear compound (n-Bu4N)2[Mo2O2(micro-S)2(dmit)2] [(n-Bu4N)2[2]], which is formed via oxidation in air from the intermediate (n-Bu4N)2[Mo3(micro3-S)(micro-S)3(dmit)3] [(n-Bu4N)2[1]] complex. Ligand substitution of the molybdenum sulfur bridged [Mo2O2(micro-S)2(dimethylformamide)6]2+ dimer with the sodium salt of the dmit dithiolate also affords the dianionic compound (n-Bu4N)2[2]. The whole series, (n-Bu4N)2[Mo2O2(micro-Se)2(dmit)2] [(n-Bu4N)2[3]], (n-Bu4N)2[W2O2(micro-S)2(dmit)2] [(n-Bu4N)2[4]], (n-Bu4N)2[W2O2(micro-Se)2(dmit)2] [(n-Bu4N)2[5]], and (n-Bu4N)2[Mo2O2(micro-S)2(dmid)2] [(n-Bu4N)2[6]; dmid = 1,3-dithiole-2-one-4,5-dithiolate], has been synthesized by the excision of the polymeric (Mo3Q7Br4)x phases with PPh3 or 1,2-bis(diphenylphosphanyl)ethane in acetonitrile followed by the dithiolene incorporation and further degradation in air. Direct evidence of the presence of the intermediates with the formula [M3Q4(dmit)3]2- (M = Mo, W; Q = S, Se) has been obtained by electrospray ionization mass spectrometry. The crystal structures of (n-Bu4N)2[1], (PPh4)2[Mo2O2(micro-S)2(dmit)2] [(PPh4)2[2]; PPh4 = tetraphenylphosphonium], (n-Bu4N)2[2], (n-Bu4N)2[4], (PPh4)2[W2O2(micro-Se)2(dmit)2] [(PPh4)2[5]], and (n-Bu4N)2[6] have been determined. A detailed study of the gas-phase behavior for compounds (n-Bu4N)2[2-6] shows an identical fragmentation pathway for the whole family that consists of a partial breaking of the two dithiolene ligands followed by the dissociation of the dinuclear cluster.

Screening of biological properties of MoV2O2S2- and MoV2O4-based coordination complexes: Investigation of antibacterial, antifungal, antioxidative and antitumoral activities versus growing of Spirulina platensis biomass

“…The [Mo (V) 2O2E2] 2+ compounds have served for many years as small molecular models for the active centers of many molybdoenzymes. [12,20,35,[49][50][51][52][53][54][55][56] Such molybdenum-sulfur bridged systems are indeed involved in certain enzymatic electron transfer processes and therefore an antioxidant activity can be expected. Here we have tested the possibility of such biological application by measuring the radical scavenging capacity against two common oxidant radicals: ABTS •+ and DDPH • .…”

The dithiolene ligand and tetrathiafulvalene precursor molecules 4,5-bis(bromomethyl)-1,3-dithiol-2-one and 4,5-bis[(dihydroxyphosphoryl)methyl]-1,3-dithiol-2-one

“…Structurally characterized molecules having the 1,3-dithiol-2-one moiety are not uncommon, although it is noteworthy that the majority of such examples incorporate this fragment as part of a tetrathioethylene group, the opposing side of which is either chelated to a transition metal (Yang et al, 1991;Kobayashi et al, 1992;Fourmigué et al, 1998;Keefer et al, 1998;Smucker et al, 2003;Llusar et al, 2005;Faulmann et al, 2006;Rabaça et al, 2006;Nomura & Fourmigué, 2007;Llusar et al, 2008) or a heavy main group element (Chohan et al, 1999;Avarvari & Fourmigué, 2003), or is alkylated (Simonsen et al, 1990;Xue et al, 2003;Nomura et al, 2009) or arylated (Yu et al 1995). Of the crystallographically identified molecules that might be compared with (I) and (II), the nearest and best comparison is given by 4,5-dicarbamoyl-1,3-dithiol-2one, (IV) (Baudron et al, 2003).…”

Synthesis, characterization and structure of a low coordinate desoxomolybdenum cluster stabilized by a dithione ligand

“…The former approach has resulted in molecular superconductors 5-7. While the homoleptic 1,2-dithiolene mononuclear complexes resulted in a range of geometry from square planar to trigonal prismatic, structures and properties of the polynuclear complexes of 1,2-dithiolene are yet to be fully developed,8 although such complexes are of interest as promising materials 7,9…”