Marcel H. B. Grote Gansey, Willem Verboom, Frank C. J. M. van Veggel, Victor Vetrogon, Françoise Arnaud-Neu, Marie-José Schwing-Weill and David N. Reinhoudt
Molecular modeling and molecular dynamics of a series of calix[4]arene tetracarboxylic acids and tricarboxylic acid monoamides revealed that in an aqueous environment the phenolic oxygen atoms do not participate in the complexation of Ac3+. This observation led to the design and synthesis of new calix[4]arene based ionophores, containing multiple glycine units, having an increased number of potential donor sites. Potentiometric titrations in methanol with La3+ as a non-radioactive model for Ac3+ indicated that, although the level of complexation is high for all ligands, a new calix[4]arene derivative 5 is superior at pH < 4.