Some mixed ligand complexes of Zn (II) and Cd (II) derived from phthalic acid, oxalic acid, succinic acid and nitrogen containing heterocyclic bases were prepared and had been characterized on the basis of their melting point studies, conductivity, magnetic measurements along with their infrared spectra and electronic spectroscopic studies. All complexes showed tetrahedral structure with moderate outcome of antimicrobial activity against some human pathogenic bacteria.

Antibiotic resistance has been growing at an alarming rate and consequently the activity of antibiotics has dropped dramatically day by day. Metal complex [Co (SB) (SCN)] (where, SB = 2-[(6-Amino-hexylimino)-methyl] phenol) have been reported for the purpose of searching new antimicrobial agents. The Schiff base and it's transition metal complex was characterized by means of several physiochemical and spectroscopic methods. Several biomedical toxicological properties of the complex has been determined by monitoring the parameters cell growth inhibition, survival time of tumour mice, timebody relation, causing of intraperitoneal cells and macrophages, alkaline phosphatase activity, haematological effect and biopsy of tumour. The synthesized Schiff base Co (II) complex was found to have anticancer and cytotoxic function.

Two complexes of Cu(II) and Ni(II) with the ligand N- (4-methoxybenzylidene) isonicotinohydrazide, having the formula [M(La)2]2+ (M = Cu(II) and Ni(II)) were synthesized. The ligand was synthesized by the condensation of isonicotinic acid hydrazide (isoniazid) with 4- methoxybenzaldehyde (p- anisaldehyde). The complexes were characterized by FTIR, UV-Vis spectroscopy, molar conductivity, magnetic susceptibility and evaluated for their in vitro antibacterial activity against human pathogens like gram negative Escherichia coli (E. coli) and gram positive Bacillus cereus (B. cereus)strains. The results indicate that all complexes consist of N and O coordination with metals has better antimicrobial activity.

New complexes of Cu (II) and Ni (II) of the Schiff Base, 2-(((2-((4-hydroxybenzylidene) amino)ethyl)imino)methyl) phenol were synthesized and characterized by analytical and  physico-chemical techniques including magnetic susceptibility, conductivity measurements, electronic and IR spectral studies. The infrared spectral studies revealed the tetra-dentate nature of the Schiff base in the complexes. On the basis of all characterizations, square- planar geometry has proposed for all the obtained complexes. The complexes showed moderate antimicrobial activity against Escherichia coli and Staphylococcus aureus.