Several aggregates of V2O2(μ-S)2 units. Syntheses, structures and properties of (Et4N)3{[V2S2O2(Et2dtc)2]2K}, (Et4N)2(NH4){[V2S2O2(C5H10dtc)2]2Na}, and (Et4N)3{[V2S2O2(Me2dtc)2]3Na3(H2O)} (dtc=dithiocarbamate)

Abstract

Three aggregates of V2O2(μ-S)2 units, (Et4N)3{[V2S2O2(Et2dtc)2]2K} (1), (Et4N)2(NH4){[V2S2O2(C5H10dtc)2]2Na} (2), and (Et4N)3{[V2S2O2(Me2dtc)2]3Na3(H2O)} (3) together with a mononuclear complex vanadium tri-pentamethylenedithiocarbamate have been obtained from a reaction system consisting of (NH4)3VS4, R2dtcNa (K) and PPh3 in CH3CN and structurally characterized. All the [V2S2O2(R2dtc)2]2− moieties possess very similar structure parameters and link each other by the interaction between V2O2(μ-S)2 units and alkali metal ion, which exists in O and S coordination sphere with coordinate number of 4, 5 or 6, respectively, for the three aggregate complexes. Infra red spectra of these aggregates exhibit the additional coordination of the V=O group to alkali metal, leading to red shift of the V=O stretch frequency. The 1H NMR signals of α-CH2 in the R2dtc ligands were observed to be close to those of the R2dtcNa, indicating the spin–spin coupling between both V(IV) sites in the [V2S2O2(R2dtc)2]2− moiety. The 51V NMR signals were observed at approximately 350 ppm. The cyclic voltammogram displays quasi-reversible couple at −0.60 to −0.73 V and an irreversible oxidation at 0.5–0.73 V, responsible for 3-/2-couple redox and 2- to 1- oxidation, respectively, of the [V2S2O2(R2dtc)2]2− moieties. Variable-temperature magnetic susceptibility study exhibits strong antiferromagnetic exchange interactions existing between the two V(IV) sites in the V2O2(μ-S)2 units.