Peroxido Complexes of Vanadium(V) as Ligands. Crystal Structures of [Cd(NH3)6][{VO(O2)2(OH)}2{μ-Cd(NH3)4}] and [{VO(O2)2(Im)}2{μ-Cu(Im)4}] (Im = Imidazole)

Two novel heterometallic complexes [Cd(NH3)6][{VO(O2)2(OH)}2{μ-Cd(NH3)4}] (2) and [{VO(O2)2(Im)}2{μ-Cu(Im)4}] (3) (Im = imidazole) containing peroxidovanadium complexes as metalloligands were prepared and characterized by spectral methods. X-ray single-crystal analysis revealed the presence of unique trinuclear complexes in the crystal structures of 2 and 3. The structure of 2 contains an anionic complex, whose two {VO(O2)2(OH)}2– ions are interconnected by a {μ-Cd(NH3)4}2+ group. Compound 3 is a trinuclear neutral complex comprising two {VO(O2)2(Im)}− ions and a single bridging {μ-Cu(Im)4}2+ group. The bonding via an equatorial OH– ligand in 2 and via a doubly bonded apical oxygen atom in 3 represents coordination modes previously unobserved for diperoxidovanadium complexes. Compared with complex 2, density functional theory studies reported decreased Cu−μ-O bond orders and increased μ-O–V bond orders in 3, in accordance with the expected Jahn–Teller distortion of the latter complex.