Synthesis and electronic, magnetic and E.s.r. studies of some bimetallic alkoxides of copper(II) with niobium(V) and tantalum(V)

Abstract

Novel bimetallic alkoxides of copper(II) of the type Cu[M(OPr-i)₆]₂ (M = Nb or Ta) have been synthesised by the interaction of CuCl₂ (1 mol) with K[M(OPr-i)₆] (2 mol). These bimetallic isopropoxides undergo facile alcohol interchange with primary alcohols such as MeOH, EtOH, n-PrOH and n-BuOH. However, with t-BuOH, the reaction cannot be driven to completion even under prolonged continuous azeotropic fractionation of the liberated i-PrOH and the final product corresponded in analysis to Cu[Ta(OPr-i)₂(OBu-t)₄]₂.I.r., electronic and electron spin resonance spectral and magnetic susceptibility measurements indicate a distorted octahedralD 4h geometry for copper(II) in these bimetallic alkoxides.