Structural, anticancer and antioxidant studies of 1-oxomelamine and its copper(II) complex

The condensation of melamine with 2-benzoylpyridine yielded a Schiff’s base(L 1 , MBP). The product showed the characteristic IR and NMR spectral peaks due to ketimine(>C N), aromatic ring and –NH 2 groups. 15 N NMR of MBP indicated –NH 2 (82.51 ppm), melamine nitrogen(174.52 ppm) and pyridine nitrogen (316.59 ppm). When MBP ligand was refluxed with Cu 2+ in ethanol yielded 1-oxomelamine(L 2 ), an oxidized product of MBP which formed a complex [Cu(L 2 ) 2 (H 2 O)]·H 2 O (L 2 =1-oxomelamine). The elemental analyses and TG-DSC inferred that one of the –NH 2 groups of melamine is oxidized. The deprotoned oxygen coordination, ring nitrogen and the aqua ligand complete five coordination of Cu 2+ . The photoluminescence showed intense emission peaks at 544 and 572 nm on excitation at 265 and 280 nm. The complex showed higher intense emission peaks than the ligand (MBP). This is due to vibrational relaxation occurring via d→d energy levels while relaxing to the ground state. The EPR spectrum at LNT showed hyperfine splitting in the g ӏӏ component of the Cu 2+ centre, showing a square pyramid geometry. TG-DSC showed a loss of two water molecules. The anticancer activity by MTT assay method indicated that IC 50 value is 38.5 μM, indicating a good anticancer activity. The antioxidant properties of the complex was investigated by DPPH assay, FERA and SOD activity studies.