Superoxide scavenging and antimicrobial activities of novel transition metal complexes of oxydiacetate dianion as primary ligand: spectral characterization, cyclic voltammetric investigations and crystal structure.

Abstract Complexes of stoichiometries [M(oda)(4-pic)H 2 O]· x H 2 O [M = Cu( 1 ), x  = 2; Co ( 2 ), x  = 4; Ni ( 3 ), x  = 2; ] [Fe(oda)(4-pic)]·Cl ( 4 ) and {[Cu(2-pa) 2 ]·2H 2 O} n ( 5 ) (H 2 oda = oxydiacetic acid, 4-pic = 4-picoline and 2-paH = 2-picolinic acid) were prepared to explore their uses as possible models for mono- and poly-nuclear metallo-pharmaceuticals. The chemical structures were elucidated by IR, FAB-Mass, 1 H, 13 C NMR, EPR and UV–visible (ligand field) spectral analyses. Electrochemical investigations are consistent with formation of stable quasi-reversible redox Co II/III and Cu II/III couples in the solution. Single crystal X-ray data of the complex ( 5 ) indicated a 1D coordination polymeric structure with extensive H-bonding to form supramolecular frameworks. The antimicrobial activities were examined against Escherichia coli (k-12), Bacillus subtilis (MTC-121), Staphylococcus aureus (IOASA-22), Salmonella typhimurium (MTCC-98), Candida albicans , Aspergillus fumigatus and Penicillium marneffei . The superoxide dismutase (SOD) activities of the Cu(II) complexes ( 1 and 5 ) were assessed employing nitrobluetetrazolium (NBT) assay.