A new lower rim calyx[4]arene derivative with mixed pendant arms containing both soft and hard ligand sites. Crystal structures of the ligand and its complexes with sodium and lead(II) - Castellano, Eduardo Ernesto; Namor, Angela F. Danil de; Samir, C.; Piro, Oscar E.; Polikarpov, Igor (Annual Meeting of the American Crystallographic Association, 2003)