Structural study of four benzyloxybenzoic acids and benzyloxyanilines using X-ray powder diffraction: interplay of strong and weak intermolecular interactions

Abstract

Crystal structures of two benzyloxybenzoic acids (1 and 2) and two benzyloxyanilines (3 and 4) have been solved from laboratory X-ray powder diffraction data using the direct space methodology. The refinements of structures 1, 2, 3 and 4 have been carried out following the Rietveld method. The nature of intermolecular interactions in 1–4 has been analyzed through the Hirshfeld surfaces and 2D fingerprint plots. The COOH functional group generates a cyclic R22(8) synthon via intermolecular O–H⋯O hydrogen bonds in 1 and 2. An interplay of O–H⋯O and C–H⋯O hydrogen bonds, and C–H⋯π interactions in 1 and 2 facilitates the formation of three-dimensional supramolecular frameworks in 1 and a one-dimensional step-like architecture in 2. While the combination of N–H⋯π and C–H⋯π interactions link the molecules in 3 into parallel columns along the [100] direction, no such molecular assembly has been observed in 4. Hirshfeld surface analyses of 1–4 as well as a few related benzyloxybenzoic acid and benzyloxyaniline derivatives retrieved from the Cambridge structural database (CSD) indicate that about 90% of Hirshfeld surface areas in this class of compounds are due to H⋯H, C⋯H and O⋯H contacts.