Coordination behavior between zinc salts and L-α-methionine

The solubility properties of ZnCl2/ZnAc2/ZnSO4-Met-H2O systems at 25 degrees C in the whole cocentration range have been investigated by phase equilibrium method. The results indicate that ZnAc2 and ZnSO4 systems are both simple systems, which do not exist any compound; there are 2 complexes formed in ZnCl2 system: Zn(Met)Cl-2 and Zn(Met)(2)Cl-2. 2H(2)O. Under the direction of phase equilibrium result, 2 solid complexes have been prepared in water and characterized by chemical analysis, IR, X-ray diffraction. Their combustion energies have also been determined by means of a RBC-type-1 rotating-bomb calorimeter, and their standard enthalpies of formation, Delta(f,) (coor(s))H-empty set, have been calculated which are (-828.32 +/- 3.00) kJ mol(-1) and (-1 117.08 +/- 6.15) kJ.mol(-1), respectively.