Template synthesis of novel 16-membered tetraazamacrocyclic transition metal complexes : DNA cleavage and antimicrobial studies

Abstract

A new series of 16-membered tetraazamacrocyclic complexes of type [ML]X 2 [where M=Ni, Co, Cu, Zn, Hg, VO IV , Cd II and Mn II ; X 2 = 2Cl - , SO 2- 4 ] by incorporating an N 4 donor site has been synthesized via the template condensation of m-phenylenediamine, formaldehyde, p-anisidine and metal salts in 1 : 2 : 1 : 0.5 molar ratio. The structural features of the complexes have been confirmed by microanalytical data, IR, UV-Vis, 1 H NMR, ESR and CV techniques. The UV-Vis, magnetic susceptibility and ESR spectral data of the complexes suggest a square-planar geometry around the central metal ion except VO IV complex which has square-pyramidal geometry. The electrochemical behaviour, the anodic and cathodic potential and the number of electrons transferred were calculated using cyclic voltammogram. The X-band EPR spectrum of copper complex in DMSO at 300 K and 77 K were recorded and its salient features are reported. The antimicrobial data show good results. The nuclease activity of the above metal complexes shows that only copper complex cleaves CT-DNA through redox chemistry in the presence of oxidant.