Bimetallic Alkoxides of Nickel(II) with Niobium(V) and Tantalum(V)

A new class of bimetallic isopropoxides of nickel(II) with niobium and tantalum with the general formula, Ni[M(OPr')6]2, (where M = Nb or Ta) have been synthesized by the reaction of nickel chloride isopropanolate, NiCl2-A:Pr'OH, with potassium hexaisopropoxy metalates, KM(OPr')6, (M = Nb or Ta) in the molar ratio 1:2. These derivatives have been characterized by elemental analyses, molecular weight determinations, infrared and visible reflectance spectro­ scopy in addition to magnetic susceptibility measurements. Alcohol interchange reactions of these bimetallic alkoxides have also been studied. On the basis of above studies, an octahedral geom­ etry has been assigned to Ni(II) in primary bimetallic alkoxides while in secondary derivatives, it appears that there exists an equilibrium between octahedral and tetrahedral forms.