Similarities and differences in the crystal packing of methoxybenzyl and methoxyphenylethyl-1,3,4-oxadiazole-2(3H)-thiones

Abstract

This work reports the crystal and molecular structures of five 1,3,4-oxadiazol-2(3H)-thiones derived from 2, 3 and 4-methoxy substituted 2-phenylacetic acid and 2- and 4-methoxy substituted 3-phenylpropanoic acid. The methoxybenzyl-1,3,4-oxadiazol-2(3H)-thiones are V-shaped while the corresponding methoxyphenylethyl-systems are close to planar, which impacts the solid state molecular packing arrangement. For molecules 1–4, inversion related N–H⋯S hydrogen bonds generating R²₂(8) rings dominate the packing, supported by an eclectic mix of C–H⋯O, C–H⋯S, C–H⋯π and π⋯π contacts that stack the molecules into interconnected columns. In contrast, each of the two unique molecules in the asymmetric unit of 5 forms N–H⋯O contacts with like molecules augmented by C–H⋯S contacts for one molecule and C–H⋯O contacts for the other to generate planar layers that are interconnected though a series of π⋯π stacking interactions.