THERMOANALYTICAL BEHAVIOR OF HISTIDINE COMPLEXES WITH TRANSITION-METAL IONS

The tendency of histidine to form biologically important complexes wit h transition metal ions is well known. However, in the literature ther e is little information about the thermochemical behaviour of these co mplexes in the solid state, and the results are often contradictory. I n this work, the synthesis and the thermoanalytical investigation of c omplexes of formula MeHis(2), MeHis(2)(NO3)(2) and MeHis(2)(NO3)(2) ar e reported, with Me = Co(II), Ni(II) or Cu(II) and His = histidine. Th e results show anomalous behaviour for histidine as a ligand compared with imidazole and its derivatives, in metal-ligand-nitrate ion intera ctions.