[Mo2O2S2]-Based Oxothiomolybdates and Their Reactivity with Pyrazole and Triazole

Extending the family of oxothiomolybdates, the interaction of the cyclic anion [Mo8O8S8(OH)8(C2O4)]2− and the complex [Mo4O4S4(C2O4)5]6− with organic compounds of the azole series—pyrazole (pzH) and 1,2,4-triazole (trzH) in water solution and in the melt of ligands was investigated. In water solution pyrazole plays only the role of cation (upon protonation) to form the complex (pzH2)2[Mo2O2S2(C2O4)2(H2O)2]. While in the reaction in melt of pzH in the case of the initial cyclic anion, the resulting anionic product [Mo6O6S6(pz)6(MoO4)]2− represents a pioneering example of a cyclic oxothiometalate Mo6 anchored by the coordination of six bridging pyrazolates (pz), complemented by a MoO42− core. At the same time, the interaction of [Mo4O4S4(C2O4)5]6− with pzH and trzH melts yields the binuclear clusters [Mo2O2S2(C2O4)2L2]2−, where L = pzH or trzH. The composition and structures of the compounds were determined using a variety of physicochemical methods, including single-crystal X-ray diffraction analysis.