Copper(II) and nickel(II) complexes of pyrazole derived ligands: Synthesis, characterization and coordinating properties of two substituted thiocarbamyl pyrazoles, 3,5-dimethyl-1-N-methyl/ethyl thiocarbamyl pyrazole (HL_1, HL_2), potential ligands fo

摘要

The solid complexes of Cu(II) with different counterions and Ni(II) having no counterions with 3,5-dimethyl-1-N-methyl thiocarbamylpyrazole (HL_1) and 3,5-dimethyl-1-N-ethyl thiocarbamylpyrazole (HL_2), the ligands having coordination function of the pyrazole ring and the thiocarbamido group, have been prepared and their geometries established on the basis of molar conductance, magnetic susceptibility, IR, UV and visible spectral data. Magnetic and spectral features indicate paramagnetic [Cu(HL_1/HL_2)X_2] (X = Cl, Br), [Cu(HL_1/HL_2)_2] (ClO_4)_2 as either planar or tetragonally distorted octahedral species with the ligands in the neutral "thione" form, while Ni(L_1/L_2)_2 as the diamagnetic square planar species with the ligands in the deprotonated "thiol" form. X-ray crystallographic studies of Ni(L_2)_2 has unambiguously proved the distorted square planar environment around the central nickel(II) ion; the ligand molecules are cis-coordinated to the nickel(II) ion.