Novel Heterotetranuclear V2Mo2 or V2W2 Complexes with 4,4′-Di-tert-butyl-2,2′-bipyridine: Syntheses, Crystal Structures, and Catalytic Activities

Two novel heterotetranuclear complexes [V2O2-(mu-MeO)(2)(mu-WO4)(2)(4,4'-(t)Bubpy)(2)] (1) and [V2O2(mu-MeO)(2)(mu-MoO4)(2)(4,4'-(t)Bubpy)(2)] (2) were synthesized, and the solid state structures of these complexes were revealed by single crystal X-ray crystallography. The heterotetranudear complexes 1 and 2 are centrosymmetric building blocks, considered as consisting of two [VO(4,4'-tubpy)](3+) units bridged mu-MO42- (M = W or Mo) anions connected with methoxy groups. Furthermore, catalytic activities of 1 and 2 in the alcohol oxidation with hydrogen peroxide as terminal oxidants in water as solvent were investigated.