Premium
Intramolecular stacking interaction in mixed‐ligand complexes containing ATP 4− and aromatic N ‐heterocyclic ligands
Author(s) -
XueYi Le,
FuHai Wu,
XiaoFeng He,
FenYun Song,
LiangNian Ji
Publication year - 1998
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19980160410
Subject(s) - chemistry , intramolecular force , moiety , stacking , potentiometric titration , crystallography , ligand (biochemistry) , ionic strength , ring (chemistry) , aromaticity , stereochemistry , ternary operation , titration , aqueous solution , inorganic chemistry , molecule , ion , organic chemistry , receptor , biochemistry , computer science , programming language
The stability constants of the binary ML 2+ and ternary M(ATP)L 2− complexes, where L=Iq (isoquinoline) or BIm (benzimidazole) and M=Zn 2+ or Cd 2+ , have been determined by potentiometric pH titration in aqueous solution at I =0.1 mol/L (NaClO 4 ), T =25°C. The stability of the ternary complexes characterized by Δlog K M =logK M(ATP)L M(ATP)L ‐ log K M ML corresponding to the equilibrium M(ATP) 2− + ML 2+ = M(ATP)L 2− + M 2+ in higher than what would be expected on statistical grounds. The increase may be related to the stacking interaction between the aromatic ring of the ligands L and the purine moiety of ATP 4– . 1 H NMR studies of Zn 2+ /ATP 4− /L confirm the presence of stacking in the ternary complexes. It is concluded that the strength of the intramolecular stacking interaction ia dependent on the structure of the aromatic ring of the ligand L and the formation of a metal ion bridge. Possible implications an discussed briefly.