Crystal Engineering Approach toward Selective Formation of an Asymmetric Supramolecular Synthon in Primary Ammonium Monocarboxylate (PAM) Salts and Their Gelation Studies

A crystal engineering approach assisted
by Cambridge Structural
Database (CSD) analyses was adopted in synthesizing a new series of
primary ammonium monocarboxylate (PAM) salts derived from variously
substituted phenylacetic acid (PA) and chiral amines
(R)- and (S)-1-phenylethyl amines
(PEA) with the aim of ascertaining an asymmetric one-dimensional
(1D) PAM synthon (designated as synthon W) over the other symmetric
possibility (synthon X). Characterization of 32 such PAM salts by
single crystal X-ray diffraction (SXRD) revealed the exclusive formation
of synthon W. The results suggested that the chiral ammonium components
must have played a crucial role in generating exclusive formation
of synthon W. Interestingly, about 28% of the PAM salts thus synthesized
herein displayed gelation ability thereby emphasizing the role of
1D PAM synthon W in gelation.