Investigation of supramolecular synthons in the crystals of N-(aryl)-succinamic acids and N-(aryl)-maleamic acids: A case study of 4-oxo-4-(pyridin-2-ylamino)butanoic acid

Abstract

Abstract 4-Oxo-4-(pyridin-2-ylamino)butanoic acid crystallizes with two symmetry independent molecules (A and B) in the asymmetric unit. The crystal structure features hetero R 2 2 ( 8 ) synthon comprising of N H⋯O = C(acid) and O H⋯Npyridyl hydrogen bonds between the molecules A and B resulting in one-dimensional (1D) helical columns running down the a axis which are further stabilized by C H⋯O = C(acid) interactions. The C H⋯O = C(amide) interactions characterized by R 2 2 ( 14 ) rings between the molecules of the neighbouring channels result in a 1D architecture. Hirshfeld surface analysis comprising of dnorm surface and 2D Fingerprint plot (FP) analyses revealed that the maximum contribution to the Hirshfeld surfaces of A and B are from H⋯H contacts followed by O⋯H/H⋯O contacts. In the crystal structure of the reported N-(aryl)-succinamic/maleamic acids, the most repetitive supramolecular synthons are either amide…acid C(7) chains or a combination of acid…acid R 2 2 ( 8 ) homodimers and amide…amide C(4) chains, which are very different from the one observed in the present structure.