Molecular structures of 3,6-di(hexylthioureido)acridine conformers, their protonation, 1H NMR and IR analyses: Theoretical and experimental studies

The optimized structures of the 3,6-di(hexylthioureido)acridine conformers were obtained using density functional theory (DFT) and ONIOM methods. Three conformers of 3,6-di(hexylthioureido)acridine and their corresponding protonated forms were found. Single-point energies calculations were obtained using second-order Møller-Plesset at the MP2(fc)/6-31G(d) level. The computed 1H NMR chemical shifts referenced to TMS in DMSO for all conformers were obtained. The presence of symmetrical conformers of the neutral and protonated structures were confirmed by the 1H NMR measurement. The measured and computed IR spectra of the neutral and protonated species of 3,6-di(hexylthioureido)acridine were obtained and compared.