Complexes of Cu(II), Co(II) and Ni(II) with pyrazole-derived ligands. Crystal structure of {bis[3-phenyl-5-(2-pyridyl)pyrazolato, kappa N-1 :kappa N-2]copper(II)}

摘要

The reaction of the pyrazole derived-ligands 3-phenyl-5-(2-pyridyl)pyrazole (HL0) and 3-phenyl-5-(6-methyl-2-pyridyl)pyrazole (HL1) with Cu((CHCOO)-C-3)(2), Co(CH3COO)(2) and Ni(CH3COO)(2) was carried out. Products were characterised by elemental analyses, conductivity measurements and infrared and electronic spectroscopy. The IR spectra of complexes display the typical absorption bands of pyrazole-derived ligands. The nature of the complexes depends on the metal. M, the ligand, HL, and the M:HL ratio: Ni(HL)(2)(CH3COO)(2), Cu(L)(2), (HL = HL0, HL1), Co(L-0)(2). In the complexes of Co(II) and Cu(II) the pyrazole is deprotonated, the band nu (N-H) was not observed in IR spectroscopy. The crystal structure of [Cu(L-0)(2)] consists of discrete centrosymmetric molecules involving a co-ordinated CuN(pz)(2)N(py)(2) core with planar geometry. The anionic ligand L-0 is not completely planar. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 42]