The first thermochromic vanadium(IV)alkoxide system

摘要

The green crystalline,homoleptic vanadium(IV)alkoxide[V_2(mu-OPr~i)_2(OPr~i)_6](I)has been reproducibly prepared in more than 60% yield;its identity was confirmed by chemical and physical methods including single-crystal X-ray diffractometry.Complex I is thermochromic in solution,changing reversibly from royal blue to gold yellow when cooled from 300 to 210 K.The assignment of this thermochromic behaviour to a mononuclear(5 = 1/2)(reversible)binuclear(S - 1)solution equilibrium is discussed.Complex I is a potential precursor of industrially-relevant vanadium-(IV),-(V)and mixed-valence vanadium oxides.