New Hybrid (E)‐4‐((pyren‐1‐ylmethylene)amino)‐N‐(thiazol‐2‐yl)benzenesulfonamide as a Potential Drug Candidate: Spectroscopy, TD‐DFT, NBO, FMO, and MEP Studies**.

A novel pyrene‐sulfathiazole‐based potential drug candidate 3 was designed, successfully synthesized by a condensation reaction of pyrenecarboxaldehyde (1) with sulfathiazole (2) in good yield, and fully characterized by NMR, IR, UV‐Vis, and HRMS spectroscopic techniques. The TD‐DFT/B3LYP calculations displayed that the recorded peaks at 396, 377, 280, and 236 nm were due to the mainly n‐π* and partially π‐π* transitions that occurred on pyrene, azomethine, and sulfathiazole moieties. The NBO results disclosed that the electron delocalizations happened onto sulfathiazole, aromatic rings (pyrene and Ph‐), and azomethine groups had the main responsibility of the lowering stabilization energy of compound 3. The NMR shifts were calculated by using the GIAO approaches in the DMSO phase and compared with the relevant data recorded. The thermodynamic and quantum chemical quantities were used for elucidating the physicochemical properties and reactivity behavior, in THF, DMSO, and water simulation environments. Accordingly, the calculated DM (D) and α (au) order of compound 3 were calculated in the order of vacuum<THF<DMSO<water, which indicated that the stability and thus reactivity of the compound strongly depended on the solvent environment. The FMO studies implied that the electron‐donating possibility of compound 3 was dominant to the electron‐accepting potency. In this work, the SMD version of IEFPCM was used in solvent media simulations. [ABSTRACT FROM AUTHOR]