Synthesis, Characterization and Biological Activity of Chromium(III), Manganese(II), Cobalt(II), Nickel(II), Copper(II) and Zinc(II) Complexes with New Schiff Base Derived from 6-methylquinoxaline-2, 3(1H,4H)-dione and Diethylenetriamine

The new metal complexes of chromium(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) were prepared by direct reactions of their metal chlorides with new Schiff base, ((3Z)-3,3'-((azanediyl-bis(ethane-2,1-diyl))bis(azanylylidene))bis(6-methyl-3,4-dihydroquinoxalin-2(1H)-one)) and fully characterized on the basis of GC-MS, 1H ,13C NMR spectra and CHNM elemental analyses. The magnetic susceptibility of solid complexes and their molar conductance in DMSO solutions revealed the octahedral geometry for all complexes with [ML(H2O)2]Cl2 (M:Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) and [CrL(H2O)Cl]Cl2. Furthermore, the antimicrobial activity of the complexes were scanned against two bacteria and fungi and it is found that the cobalt(II),copper(II) and zinc(II) complexes showed the highest inhibition zone towards the selected microorganisms where as the other complexes exhibited medium activity with relative to standard antibiotic Ciproflaxine of 20 µg/ml. Furthermore, the nickel(II),copper(II) and zinc(II) complexes exhibited remarkable inhibition zones against Candida albicans and Aspergillus flavus.