Recognition and Binding of Aliphatic Dicarboxylic Acids C4 - C10 by Diiminocalix[4]arene

Host-Guest complexation of 5,17-bis-(N-tolyliminomethyl)-25,27-dipropoxycalix[4]arene with aliphatic dicarboxylic acids C4 - C10 has been studied in water-organic solution by the RP HPLC and molecular modeling methods. The stability constants (log K-A = 2.56 - 3.05) of the supramolecular complexes are depended on structure, pKa and log P values of the acids. The complexation is determined by the hydrogen bonds of the COOH group of the dicarboxylic acids with nitrogen atoms at the upper rim or oxygen atoms at the lower rim of the calixarene.