Coordination of 4-mercapto-1,2-dithiole-3-thione heterocycles to ruthenium(II) and molybdenum(VI) centres

Deprotonation of 4-mercapto-1,2-dithiole-3-thiones with NEt3 followed by reaction with [Ru(H)(Cl)(CO)(PPh3)3] affords virtually quantitative yields of turquoise [Ru(H)(RC3S4)(CO)(PPh3)2] (R = Ph, Mes) in which the heterocycle is bound as a bidentate uninegative ligand through the two exocyclic sulfur atoms. The presence of both possible isomers in each case is indicated by NMR spectroscopy. Reaction of the 4-mercapto-1,2-dithiole-3-thiones with [MoO2(acac)2] results in displacement of the acac ligands and formation of [MoO2(RC3S4)2]. The crystal structures of [Ru(H)(MesC3S4)(CO)(PPh3)2] and [MoO2(MesC3S4)2] have been determined.