Infrared Spectroscopic Characterization of Calcium and Barium Hydrazone Complexes

Hydrazones have attracted considerable interest on account of their biological activities. Introduction of calcium and barium metal ions into m- and p-nitrobenzoic hydrazones is expected to modify these biological properties for enhanced activity and versatility. The ligands were synthesized from the parent acids. The complexes have been characterized using C, H and N microanalyses and IR spectrometry. The IR spectral data of the ligands and complexes revealed bonding via the C=O and C=N groups. The suggested metal to ligand stoichiometries are: [M (m-NBH)x]Cl₂.yH₂O, x, y = 1 and 4 for M = Ca; x, y = 2 and 3 for M = Ba respectively. [M(p-NBH)x]Cl₂.yH₂O, x, y = 1 and 12 for M = Ca; x, y = 1 and 3 for M = Ba respectively. The structural deductions are tentative pending future X-ray structural studies.