From Small {Mo2O4}2+ Aggregates to Infinite Solids

Mononuclear oxohalomolybdates(V) readily generate in the mixtures of alcohols and pyridines through a series of substitution and dimerization reactions, still reactive dinuclear {Mo2O4}2+ fragments which assemble together into larger cluster species. In all, the {Mo2O4}2+ unit with the two molybdenum atoms connected by a single metal-metal bond, appears as a recurrent structural motif, either as a single {Mo2O4}2+ unit in dinuclear compounds or as assemblies of two, three, four or six units through bridging oxygen donor ligands in tetranuclear, hexanuclear, octanuclear and dodecanuclear compounds, respectively. Pyridine, halide, alkoxide and alcohol ligands occupy the peripheral positions of the molybdenum oxide cores. Their structures will be presented in terms of different arrangements and connectivities among the basic dinuclear building blocks. By using a suitable linker, an oxalate adopting a bisbidentate binding mode was shown to serve the purpose, the {Mo2O4}2+ units were connected into infinite chains.