Different supramolecular architectures mediated by different weak interactions in the crystals of three...

The synthesis and evaluation of the pharmacological activities of molecules containing the sulfonamide moiety have attracted interest as these compounds are important pharmacophores. The crystal structures of three closely related N-aryl-2,5-dimethoxybenzenesulfonamides, namely N-(2,3-dichlorophenyl)-2,5-dimethoxybenzenesulfonamide, C₁₄H₁₃Cl₂NO₄S, (I), N-(2,4-dichlorophenyl)-2,5-dimethoxybenzenesulfonamide, C₁₄H₁₃Cl₂NO₄S, (II), and N-(2,4-dimethylphenyl)-2,5-dimethoxybenzenesulfonamide, C₁₆H₁₉NO₄S, (III), are described. The asymmetric unit of (I) consists of two symmetry-independent molecules, while those of (II) and (III) contain one molecule each. The molecular conformations are stabilized by different intramolecular interactions, viz. C-H...O interactions in (I), N-H...Cl and C-H...O interactions in (II), and C-H...O interactions in (III). The crystals of the three compounds display different supramolecular architectures built by various weak intermolecular interactions of the types C-H...O, C-H...Cl, C-H...π(aryl), π(aryl)-π(aryl) and Cl...Cl. A detailed Hirshfeld surface analysis of these compounds has also been conducted in order to understand the relationship between the crystal structures. The d_norm and shape-index surfaces of (I)-(III) support the presence of various intermolecular interactions in the three structures. Analysis of the fingerprint plots reveals that the greatest contribution to the Hirshfeld surfaces is from H...H contacts, followed by H...O/O...H contacts. In addition, comparisons are made with the structures of some related compounds. Putative N-H...O hydrogen bonds are observed in 29 of the 30 reported structures, wherein the N-H...O hydrogen bonds form either C(4) chain motifs or R₂²(8) rings. Further comparison reveals that the characteristics of the N-H...O hydrogen-bond motifs, the presence of other interactions and the resultant supramolecular architecture is largely decided by the position of the substituents on the benzenesulfonyl ring, with the nature and position of the substituents on the aniline ring exerting little effect. On the other hand, the crystal structures of (I)-(III) display several weak interactions other than the common N-H...O hydrogen bonds, resulting in supramolecular architectures varying from one- to three-dimensional depending on the nature and position of the substituents on the aniline ring.