Thermal study of some new Ni(II) and Cu(II) complexes with ligands derived from N,N-dimethylbiguanide as potential antimicrobials

The reaction between [M(DMBG)(2)]center dot nH(2)O ((1) M:Ni, n = 0; (4) M:Cu, n = 1), ammonia/hydrazine and formaldehyde in methanol resulted in new complexes of type [ML]center dot nH(2)O ((2) M:Ni, L:L-1, n = 0; (3) M:Ni, L:L-2, n = 0, (5) M:Cu, L:L-1, n = 0 and (6) M:Cu, L:L-2, n = 3; HDMBG: N,N-dimethylbiguanide, L-1 = ligand resulted from ammonia system and L-2 = ligand resulted from hydrazine system). The features of complexes have been assigned from microanalytical, IR and UV-Vis data. The thermal transformations of compounds are complex processes according to TG and DTG curves including melting, phase transition, dehydration, oxidative condensation of -C=N- units as well as thermolysis processes. The final products of decomposition are the most stable metal oxides.