The intramolecular stacking interaction in ternary complexes formed by ATP and heteroaromatic N-base ligands

The stability constants of binary ML(2+) complexes formed by Zn2+ or Cd2+ (M(2+)) and isoquinoline or benzimidazole(L) and ternary M(ATP)L(2-) complexes containing ATP in addition were determined by potentiometric pH titration in aqueous solution. It has been found that there is an intramolecular stacking interaction between the heteroaromatic N-Base ligands and the base part of ATP in the ternary complexes, this interaction may have relation to the structure of the aromatic rings of the L ligands.