Synthesis and structure of a high nuclearity oxomolybdenum(V) complex, [(C5Me5RhIII)8(MoV12O36)(MoVIO4)]2+

Hydrothermal treatment of MoO[sub 3][center dot]2H[sub 2]O with [(C[sub 5]Me[sub 5]Rh)[sub 2](OH)[sub 3]]Cl yields a Cl[sup [minus]]/OH[sup [minus]] salt of the [(C[sub 5]Me[sub 5]Rh)[sub 8](Mo[sub 13]O[sub 40])][sup 2+] cation. This species contains a central [(Mo[sup V][sub 12]O[sub 36])(Mo[sup VI]O[sub 4])][sup 14[minus]] core having the [Al[sub 13]O[sub 4](OH)[sub 24](H[sub 2]O)[sub 12]][sup 7+] framework structure ([epsilon]-Keggin structure). This dodecanuclear oxomolybdenum(V) complex is comprised of six Mo-Mo dimers and shows for the first time that Mo[sup V] can form high-nuclearity polyoxoanions.