The synthesis of W–O–M (M = Al, Ti, Ni, Zn) μ–oxo clusters by hydrolysis of tungsten aminoalkoxides and their structural characterisation

Abstract

Three novel heterobimetallic W–O–M clusters have been synthesised by the hydrolysis of mixtures of W(O)(OPri)3(bdmap) with Ti(OPri)4, Zn(acac)2 and Al(OPri)3, respectively. A fourth, related W–O–Ni cluster has been obtained by adventitious hydrolysis of a mixture of W(O)(OMe)4 and Ni(dmap)2 [Hbdmap=1,3-bis-(dimethylamino)-propan-2-ol; Hdmap=1-(dimethylamino)propan-2-ol]. W2Ti2(O)2(μ2–O)4(OPri)6(μ2–bdmap)2 (1) adopts a central W2Ti2O6 core with an adamantane-like structure while W2Al2(O)2(OPri)2(μ2–O)4(μ2–bdmap)4 (3) has an analogous W2Al2O6 core but which adopts an isomeric cube arrangement with two parallel sides missing. W2Zn2(O)2(μ2–O)3(OPri)2(acac)2(μ2–bdmap)2 (2) is similar to 1 but the two bidentate acac groups result in the elimination of one μ2–O bridge; the resulting W2Zn2O5 core forms an adamantane structure with one W–O–Zn linkage missing. In contrast, W4Ni4(O)4(OMe)4(μ2–OMe)4(μ2–O)4(dmap)8 (4) forms a tetrameric square of four linked W–O–Ni units.