METAL-COMPLEXES WITH DISUBSTITUTED OXAMIDIC LIGANDS

Three oxamidic ligands have been prepared by reaction of oxalyldichlor ide with the appropriate amine H2NC6H4P(C6H5)(2) (H(2)A), H2NC2H4(NC5H 4) (H2B) and H2NC2H4SC6H5 (H2C). They have been characterized by eleme ntal analyses, IR, NMR, mass spectrometry and for H2B by X-ray diffrac tometry. The crystals, grown from a tetrahydrofuran/diethylether solut ion, are monoclinic, space group P2(1)/c, cell dimensions a=9.503(4), b=6.278(4), c=13.083(5) Angstrom and beta=100.24(4)degrees with Z=2. T he asymmetric unit is half of the ligand molecule which shows an inver sion centre between the C-C bond of the oxamidic group. The molecule i s elongated in a three steps configuration. The reaction of H(2)A with trans-Pd(C6H5CN)(2)(Cl)(2) forms the white mononuclear cis-Pd(A) and the yellow homodinuclear trans-Pd-2(A)(Cl)(2) complexes as confirmed b y scanning electron microscopy (SEM) and EDX analyses and by an X-ray structure of Pd-2(A)(C)(2). The yellow crystals, grown from alcoholic solution, are monoclinic, space group P2(1)/c, cell dimensions a=10.33 5(5), b=10.246(5), c=16.480(6) Angstrom and beta=100.81(5)degrees with Z=2; as for H2B crystals, the asymmetric unit is half of the whole mo lecule. A distorted square planar coordination around each metal ion i s reached by the coordination of a phosphorus, an oxygen and a nitroge n atom of the ligand and a chlorine atom. H2B forms the homodinuclear nickel(II) and copper(II) complexes M(B)(X)(2) (X=Cl-, CH3COO-, ClO4-) . Crystals of the dinuclear copper(II) complex Cu-2(B) (Cl)(2)(dmso)(2 ) grown from dimethylsulphoxide, are triclinic, space group P (1) over bar, cell dimensions a=8.352(5), b=8.361(5), c=9.959(4) Angstrom, alp ha=83.39(4) beta=85.49(3), gamma=75.38(5)degrees with Z=1. Again the d inuclear entity shows a inversion centre between the two C-C bonds of the oxamide ligand. Each copper(II) ion has a distorted square pyramid al environment formed by two nitrogen atom and an oxygen atom of half oxamidic ligand, a chlorine atom and the oxygen atom of a dimethylsulp hoxide molecule; the copper-copper distance is 5.28 Angstrom. An antif erromagnetic interaction was observed for the dinuclear copper(II) com plexes. H2C does not form complexes when reacted with transition metal ions.