Dinuclear nickel(II) complex of a N2O3-donor Schiff base derived from acetylacetone and 1,3-diamino-2-hydroxypropane

The synthesis and X-ray structure of a dinuclear nickel(II) complex of the triply deprotonated pentadentate Schiff base, N,N′-(2-hydroxypropane-1,3-diyl)bis(acetylacetoneimine) (apacaH3), are reported. The complex, which was obtained by reaction of apacaH3 with nickel acetate in ethanol, has a binuclear structure of type [Ni2 (apaca)(OAc)] in which each metal centre is bound to a deprotonated enolic oxygen and an imine nitrogen from an acetylacetoneimine ‘arm’ of apaca. The nickel centres are bridged by both an alkoxide oxygen derived from the 2-hydroxypropane unit in apaca and an acetato group. Each metal centre has a distorted square-planar geometry, with the overall configuration being non-planar. This complex is isostructural with a previously-reported, copper(II) complex of similar stoichiometry, prepared by an analogous procedure from copper(II) acetate. The present result contrasts with a previous report in which apacaH3 was claimed to interact with nickel(II) acetate in ethanol in the presence of potassium ethoxide to yield a square-planar complex of the corresponding doubly deprotonated Schiff base ligand.