Formation and Transformations of Polynuclear Hydroxo- and Oxotrimethylacetate Complexes of Ni(II) and Co(II)

Abstract

Transformations of polymeric trimethylacetate complexes [M(OH) n (OOCCMe3)2 – n ] m (M = Ni (I) and Co (II)) and clusters Ni9(μ4-OH)3(μ3-OH)3(μ-O,O-OOCCMe3)(μ-O,O"-OOCCMe3)7(μ3-O,O,O"-OOCCMe3)3(μ4-O,O,O",O"-OOCCMe3)(HOOCCMe3)4(III) and Co6(μ3-OH)2(μ-OOCCMe3)10(HOOCCMe3)4(VIII), which are formed from Iand IIupon their recrystallization from nonpolar solvents, were studied. It was shown that the action of N-phenyl-o-phenylenediamine (L) on Ior IIIresults, depending on the solvent, in different tetranuclear clusters with the hydroxo bridges. For example, in benzene, the L2Ni4(μ3-OH)2(HOOCCMe3)4(μ-OOCCMe3)6complex (IX) is formed; its L molecules are coordinated in a monodentate way, whereas in acetonitrile, they chelate to give the {[o-C6H4(NH2)(NHPh)]2Ni4(μ3-OH)2(MeCN)2(OOCCMe3)2(μ-OOCCMe3)4} compound (X). Heating of Xin the presence of atmospheric oxygen yields IX, the mononuclear bissemiquinonediimine [o-C6H4(NH)(NPh)]2Ni complex (XI), and water. It was noted that the use of aniline in these reactions affords, independent of the nature of the solvent, only one (NH2C6H5)2Ni4(μ3-OH)2(HOOCCMe3)4(μ-OOCCMe3)6cluster (VI); in acetonitrile, this cluster is formed as the solvate VI· 2HOOCCMe3(VIa). When treated with ethanol, Iand IIIgive the Ni4(EtOH)6(μ3-OH)2(μ2-OOCCMe3)4(OOCCMe3)2cluster (V), which is structurally close to the known cobalt-containing analog IV. Thermolysis of IVin decalin at 170°С causes its dimerization, giving the octanuclear Co8(μ4-O)2(μ n -OOCCMe3)12complex (VII) with the tetradentate oxo bridges.