Study On Phase Chemistry And Thermochemistry Of The Complexes Of L-α-Amino Acids With Zinc Salts

The solubility properties of Zinc salts-amino acids-H2O(Znic salts=ZnAc2,ZnCl2 ; amino acid=L-ɑ-Leu/Try/Val/Thr) systems at 25℃ in the whole concentration ranges have been investigated by phase equilibrium. the phase diagram indicate that no complex is formed in the ZnAc2 salts systems and there are 6 complexes in the ZnCl2 salts systems. Zn(Leu)Cl2(15),Zn(Try)Cl2· 0.5H2O (23),Zn(Val)Cl2· H2O (19),Zn(Val)2Cl2(20),Zn(Thr)Cl2·H2O(27),Zn(Thr)2Cl2(28)。only Zn(Leu)Cl2(15) is congruently soluble in water .The 6 complexes are prepared by phase method. The composition of them are mensurated by chemical analysis which are in consistency with the results of phase equilibrium. According to the literatures, Zn(Thr)Ac2·H2O, has also been prepared. the 7 complexes above are not reported in any literature.The results of X-ray diffraction of the two complexes show that they are new species which are different from ligands. The IR of complexes reveal that the N of ɑ-amino and the O of carboxyl in the four amino acids coodinate with Zn(Ⅱ). And the coordination of Cl- and the C-OH in the Zn(Thr)Ac2·H2O have been supposed. The thermal analysis of these complexes show that the final product of the decomposition of them are all ZnO, but the processes of the decomposition are quite different. The detail analysis are reported.The combustion energies of Zn(Thr)2Cl2 has been mensurated using a precision rotating-bomb calorimeter. The standard enthalpy of combustion and standard enthalpy of formation have been computed.And the solution heat of the Zn(Leu)Cl2 and Zn(Thr)Ac2?2H2O have been mensurated on the RD496-Ⅲ micro Calorimeter. And the soluble equlibrium is supposed.