Synthesis and Spectroscopic Characterization of Cobalt(II) and Nickel(II) Complexes with 5-Methyl-1-(2´-pyridyl)-pyrazole-3-carboxamide

Abstract

A host of novel Co(II) and Ni(II) complexes with the 5-Methyl-1-(2´-pyridyl)pyrazole-3-carboxamide ligand (MPyPzCA) have been synthesized and characterized through analytical and physico-chemical data. Magnetic and electronic spectral studies classify the reported bis-chelates as 6 coordinated distorted octahedral ones. A scrutiny of the IR spectra between the ligand and its complexes and in analogy with the crystal structure analysis indicates that one ligand exercises neutral tridentate (NNO) behaviour through pyrazolyl 2_N and pyridyl 1′_N and amidic oxygen whereas the second ligand binds the same central metal atom through pyrazolyl 2_N and pyridyl 1′_N, respectively in the bis-chelates. The coordinated H₂O molecule satisfies the sixth coordination site.The anions (X) in all the cases retain their ionic nature.