Abstract:

The intra molecular interactions in complexes of Aspartic acid with divalent metal ions (Mg, Ca & Zn) M(Asp)1 were investigated in this work. The acidity constants of Asp and stability constants of M(Asp) are determined and reported as well. The effect of intra molecular interactions can be seen by comparison of these stability constants. Mg and Ca ions form weaker bonds to Asp than Zn ion. Zn(Asp) complex undergoes an intra molecular interaction and builds a chelate in two forms ( an open – isomer M(Asp)op and a closed – isomer M(Asp)cl ). The concentration independent intra molecular interaction constant for two isomers has been calculated and reported. The obtained results demonstrate that for some M(Asp) complexes the stability constant is largely affected by the affinity of metal ions for amine group. This shows a kind of selectivity of metal ions and transfer them via complex – building with the aspartate. Also all three metal ions complexes could be considered as mineral carriers. These complexes can release the minerals in human body in certain conditions ( e,g. pH – range).