Structure property relationship in two thiazole derivatives: Insights of crystal structure, Hirshfeld surface, DFT, QTAIM, NBO and molecular docking studies

Detailed structural and noncovalent interactions in two thiazole derivatives (<i>N-(4-Bromophenyl)-2-(methylthio)thiazole-5-carboxamide</i> and <i>Ethyl-5-((4-bromophenyl)carbamoyl)thiazole-4-carboxylate</i>) are investigated by single crystal X-ray diffraction study and computational approaches. The structure investigation revealed that various interactions like C-H…O, N-H…O, and N-H…N hydrogen bonds and Br…Br interactions are involved in constructing ring motifs to stabilize the crystal packing. Hirshfeld surface analysis and fingerprint plots were carried out to study the differences and similarities in the relative contribution of noncovalent interactions in both the molecules. The FMOs and other global reactive parameters are analyzed for thiazole derivatives. The strength and nature of weak interactions present in the molecule were characterized by RDG-based NCI and QTAIM analyses. Natural bond orbital (NBO) analysis unravels the importance of non-covalent and hyperconjugative interactions for the stability of the molecules in their solid state. Further, molecular docking of <i>N-(4-Bromophenyl)-2-(methylthio)thiazole-5-carboxamide</i> and <i>Ethyl-5-((4-bromophenyl)carbamoyl)thiazole-4-carboxylate</i> with SARS-Covid-19 have been carried out.