Molecular recognition of dicarboxylate ions by bis-phenylureas derived from a new dicarboxylic acid.

A new dicarboxylic acid 4 was synthesized from 1,5-dichloroanthraquinone (1) and modified to ditopic receptors for binding of diammonium and dicarboxylate salts by multiple hydrogen bonds. The cis and trans isomers of 4 were assigned by the relative binding affinities of the bis(crown ether) derivatives, 5a and 5b to alkyl diammonium dipicrates. The association constants (K-a) between p-substituted bis-phenylureas and adipate vary from 5 x 10(2) to 2 x 10(4) M(-1) in DMSO-d(6), depending on substituents in the phenyl ring. Copyright (C) 1996 Elsevier Science Ltd