Metal(II) complexes of the carbonylnitronate ligands O2NCHC(O)R- (R = Ph, OMe or OEt) and X-ray structure of (DMANH)[Ni(O2NCHC(O)Ph)(3)] (DMAN = 1,8-bis(dimethylamino)naphthalene)

New coordination compounds involving carbonylnitronate ligands O2NCHC(O)R- (R = Ph, OMe or Oft) are prepared by a synthetic procedure based on the rea ction of a nickel(II) or palladium(II) salt with benzoylnitromethane or alk yl nitroacetate in the presence of a deprotonating agent. The use of the pr oton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) in tetrahydrofuran aff ords, in high yields, the anionic complexes (DMANH)[Ni(O2NCHC(O)R)(3)] as b rilliant green solids. The benzoylnitronate complex (R = Ph) crystallises i n a monoclinic unit cell [space group P2(1)/n, a = 13.061(2), b = 16.415(2) , c = 17.827(2) Angstrom, beta = 102.7(2)degrees], which contains four octa hedral anionic nickel complexes each close to a big DMANH (+) cation. One n itronate ligand is easily replaced by two molecules of ethanol to give the neutral complexes [Ni(O2NCHC(O)R)(2)(EtOH)(2)]. The nickel is O,O'-coordina ted to the ligand through one carbonyl and one nitro oxygen atom. A differe nt coordination mode, in which only the nitro group is bonded to the metal, is, however, observed in the palladium complexes [PdCl(O2NCHC(O)R)](2) (R = OMe, Oft). (C) 1999 Elsevier Science S.A. All rights reserved.