Investigation of some (e)-4-bromo-2-methyl-6-[(phenylimino)methyl]phenol derivatives by spectroscopic, crystalographic and computational methods

Within the scope of this master thesis, new Schiff bases containing various new substituents were synthesized by using 5-bromo-2-hydroxy-3-methylbenzaldehyde and aniline derivatives. Single crystals of the synthesized compounds were obtained using suitable solvents. XRD results show that all of the compounds have phenol-imine form in the solid state. The FT-IR results are in accord with the XRD results. UV-Vis spectra of the compounds were recorded in four solvents with different dielectric constants such as hexane, chloroform, DMSO, and ethanol. According to the results of UV-Vis spectroscopy, the absence of absorption above 400 nm indicates that the compounds are in the form of phenol-imine. NMR spectra of the compounds were recorded in CDCl3. The results obtained showed that the compounds were in the form of phenol-imine according to NMR spectroscopy. In addition, computational studies of the structures were studied at the DFT/B3LYP 6-311G(d,p) theoretical level using the Gaussian 09 package program. Computationally, geometric optimizations of the compounds were done, HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital) energies were calculated and MEP (Molecular Electrostatic Potential) maps were examined. Nucleophilic and electrophilic powers were compared to determine the chemical properties of the structures. At the same time, computational FT-IR, UV-Vis and NMR analyzes were performed and the results were found to be compatible with the experimental results.