Aqueous reduction of [Cp*2W2O51]: Characterization of the triangular clusters [Cp*3W3O4(OH)(2)](2+) and [Cp*3W3O6](+) - Comparison with molybdenum

Zinc reduction Of CP * 2W2O5 in an acidified water-methanol medium affords the green 3-electron trinuclear cluster [CP*3W3O4(OH)(2)](+2), isolated and crystallographically characterized as the triflate salt, 1. Upon exposure to air, this complex is oxidized to a related 2-electron cluster, [Cp * 3W3O6], which was crystallized and characterized in three different salts, 2-4. The 3-electron cluster exhibits a near-tetragonal frozen-glass EPR spectrum, and it shows evidence of coupling of the unpaired electron to only one of the three W atoms. The two-electron cluster is diamagnetic. An electro-spray ionization MS' study revealed a stepwise expulsion of neutral [CP*WO2] units as the main fragmentation process. DFT calculations unveiled the intimate details of the electronic structures of these complexes and fully rationalized the structural and spectroscopic properties.