V4S4 cubane-like cluster: synthesis, structure and properties of (Et4N)[V4S4(C4H8dtc)6]

A cubane-type cluster compound (Et4N)[V4S4(C4H8dtc)6] was obtained from a reaction system consisting of (NH4)3VS4, C4H8dtcNH4 and PPh3 in CH3CN and the compound was structurally characterized. The four V atoms possess very similar structure parameters, implying their equivalence and electronic delocalization in the V4S4 core. The 1H NMR signals of α-CH2 in the ligating C4H8dtc ligands are observed at 4.77, 5.17 and 7.57 ppm, assignable to the terminal and bridged C4H8dtc ligands, respectively. The cyclic voltammogram displays two reversible couples at −0.80 V/−0.75 V and −0.02 V/0.01 V, responsible for 2−/1− couple and 1−/0 redox processes, respectively, of the V4S4 complex. Variable-temperature magnetic susceptibility study reveals the presence of intramolecular antiferromagnetic exchange interactions.