Trans-1,2-Cyclohexanedicarboxylic acid derivatives as pH-trigger for conformationally controlled crowns

Abstract

Conversion of trans-1,2-cyclohexanedicarboxylic acid derivatives into dianions under the action of strong bases leads to dramatic conformational changes: a conformer with diaxial position of carboxylate groups becomes predominant. Thus the trans-1,2-cyclohexanedicarboxylic acid moiety can be used for pH-induced conformational switching. The conformational energy changes upon protonation amount to 10 kJ/mol.