Nickel(II), Cobalt(II), Palladium(II) and Beryllium(II) Chelates of 2,4,6-Heptanetrione

Abstract

Abstract Divalent metal chelates of heptane-2,4,6-trione (H2daa) were synthesized and their structures were discussed. Nickel(II), cobalt(II) and palladium(II) ions gave Ni(Hdaa)2·2H2O, Ni2(daa)2·4H2O, Ni2(daa)2·4Py, Co(Hdaa)2·2H2O, Co2(daa)2·4H2O, Co2(daa)2·4Py, Pd(Hdaa)2 and Pd(Hdaa)2·2H2O respectively, while beryllium (II) ion unexpectedly gave bis (2-amino-2-heptene-4,6-dionato) beryllium (II) which resulted from an amino-derivative of the original ligand. Spectroscopic results suggested that the coordination structure of nickel(II) and cobalt(II) ions was octahedral hexacoordinate, that of palladium(II) ion square planar tetracoordinate and that of beryllium(II) ion tetrahedral tetracoordinate. NMR study of the palladium(II) chelate suggested partial enolization of an uncoordinated carbonyl group. It was also found that nickel, cobalt and platinum ions promoted catalytically the bimolecular-condensation of heptane-2,4,6-trione.