Polymorphs of Substituted p-Toluenesulfonanilide: Synthesis, Single-Crystal Analysis, Hirshfeld Surface Exploration,...

Polymorphism is an exciting feature of chemical systems where a compound can exist in different crystal forms. The present investigation is focused on the two polymorphic forms, triclinic (MSBT) and monoclinic (MSBM), of ethyl 3-iodo-4-((4-methylphenyl)sulfonamido)benzoate prepared from ethyl 4-amino-3-iodobenzoate. The prepared polymorphs were unambiguously confirmed by single-crystal X-ray diffraction (SC-XRD) analysis. According to the SC-XRD results, the molecular configurations of both structures are stabilized by intramolecular N-H···I and C-H···O bonding. The crystal packing of MSBT is different as compared to the crystal packing of MSBM because MSBT is crystallized in the triclinic crystal system with the space group P1̅, whereas MSBM is crystallized in the monoclinic crystal system with the space group P2₁/c. The molecules of MSBT are interlinked in the form of dimers through N-H···O bonding to form R₂²(8) loops, while the MSBM molecules are connected with each other in the form of an infinite chain through C-H···O bonding. The crystal packing of both compounds is further stabilized by off-set π···π stacking interactions between phenyl rings, which is found stronger in MSBM as compared to in MSBT. Moreover, Hirshfeld surface exploration of the polymorphs was carried out, and the results were compared with the closely related literature structure. Accordingly, the supramolecular assembly of these polymorphs is mainly stabilized by noncovalent interactions or intermolecular interactions. Furthermore, a density functional theory (DFT) study was also carried out, which provided good support for the SC-XRD and Hirshfeld studies, suggesting the formation of both intramolecular and intermolecular interactions for both compounds.