Metal complexes of 1-methyl-3,4-diphenylpyrazole, a ligand formed by the reaction between benzil and N,N,-dimethylhydrazine

Abstract

New complexes of the general formulae MnX 2L 2 (X = Cl,Br), MnBr 2L 3, CoX 2L 2 (X = Cl, Br, I, NCS, NO 3), NiX 2L 2 (X = Cl, NO 3), NiBr 2L 3·H 2O, NiL 2L 4·H 2O, CuCl 2L, CuBr 2L 2·H 2O, Cu(NO 3) 2L 2, ZnX 2L 2 (X = Cl, Br, NO 3, Zn(NCS) 2L 2·H 2O, CdX 2L 2 (X = I, NO 3) and HgCl 2L, where L is 1-methyl-3,4-diphenylpyrazole, have been prepared and characterized by elemental analysis, conductivity measurements, magnetic moments and spectral ( 1H-NMR, IR and electronic) studies. The ligands is formed by the reaction between benzil and N,N-dimethylhydrazine. The nitrogen of the >CN bond is the donor atom to the metal ions. The bis-ligand halide complexes are pseudotetrahedral, while the nitrate complexes contain octahedrally coordinated metal ions. The IR spectra of MCl 2L (M = Cu, Hg) are indicative of the presence of both terminal and bridging metal-halogen bonds supporting polymeric structures. The stereochemistry and the nature of the nickel(II) complexes are markedly dependent upon the anions; the chloride complex is pseudotetrahedral, the iodide square planar, the nitrate polymeric octahedral, while the proposed structural formula for NiBr 2L 3·H 2O comprises Nickel(II) atoms present in both square planar and octahedral coordination environments.