Molecular Recognition in Methanol:  The First Example of Hydrogen-Bond-Mediated Self-Association of a Calix[4]arene in Polar, Protic Solvent

Abstract

Tetraalaninecalixarene was prepared by coupling of tetraaminocalix[4]arene with alanine. It dimerizes in methanol, providing the first example of a substituted calixarene that undergoes self-association through hydrogen bonding in polar, protic solvent. The association constant in 24:1 MeOH:H2O was determined to be 29 000 M-1. Addition of arginine or lysine results in disruption of the dimer and formation of a 1:1 complex between the amino acid and the tetraalaninecalixarene. The preparation of a peptidocalixarene that associates in polar solvent opens new doors for the use of calixarenes for molecular recognition in biologically relevant environments.