The experimental X-ray diffraction and theoretical investigations of structure of some salicylaldehyde derivative Schiff bases including methoxy group

Within the scope of the thesis, molecular and crystal structures of (E)-2-[(4-ethylphenylimino)methy]-4-methoxyphenol (I) and (E)-4,6-dichloro-2-[(3,4-dimethylphenylimino)methyl]-3-methoxyphenol (II) compounds were determined. In the single crystal X-ray diffraction studies of compounds, direct methods were used in the structure solving when least squares methods were used in structure refinements. By using density functional methods in Gaussian 09W software package, the geometry optimizations with respect to the total energy of the molecules and the root mean square error values between the X-ray and the calculated geometries were obtained. The total energy chancing and the aromaticity values by means of harmonic oscillator model of aromaticity (HOMA) were found during the proton transfer process by using a potential energy surface scan calculation for each molecule. In the solid state both compounds prefer highly enol-imine form while in the solvent media compound (II) prefers keto-amine more than the enol-imine form depending on the solvent dielectric constant.