Synthesis and characterization of transition metal complexes of hydrochloride salt of 3-chlorobenzaldehyde hydralazine hydrazone: a new class of possible anti-cariogenic agents

A novel hydrazone, formed by the condensation of the hydrochloride salt of hydralazine with 3‐chlorobenzaldehyde, and its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. Their structures have been elucidated on the basis of elemental analyses, conductance measurements, magnetic moments, and spectral (infrared, 1H NMR, UV–visible, electrospray ionization (ESI) mass) and thermal studies. The bidentate behaviour of the ligand is proposed on the basis of spectral studies. Interestingly, all four complexes exhibit different geometry around the metal centre. The conductance data of the complexes suggest them to be non‐electrolytes. The ESI mass spectra of the complexes support their monomeric nature. The compounds were tested against two Gram‐positive and three Gram‐negative bacterial strains and three fungal strains. Excellent inhibitory activity is observed against the Gram‐positive bacteria Streptococcus mutans and Enterococcus faecalis which play major roles in tooth decay. Among the fungal strains used, Candida albicans is inhibited predominantly. Copyright © 2014 John Wiley & Sons, Ltd. 3‐Chlorobenzaldehyde hydralazine hydrazone and its transition metal complexes were investigated for their antimicrobial activity against two Gram‐positive and three Gram‐negative bacterial strains and three fungal strains. Excellent inhibitory activity is exhibited against Gram‐positive bacteria E. faecalis and S. mutans, which play a major role in tooth decay, and the fungal strain C. albicans.