Conclusions
The optimized geometries of the studied compounds were calculated by B3LYP/6-31G(d), B3LYP/6-31G(d,p), and B3LYP/6-311G(d,p) levels of theory and it was found to be in good agreement with the experimental data. The TD-DFT has been used to determine the UV-vis spectra of all compounds. The agreement between the calculated and experimental maximum absorption wavelengths is excellent. In addition, it can be suggested that TD-DFT method is a valuable method in the prediction of the excitation states for this type of compounds.
Another important conclusion that we can draw from these calculations is that the results of the frontier orbital calculations are indicating that the nucleophilicity (i.e.EHOMO-ELUMO) of molecule 3 is the highest among the studied molecules (Table 5). Since nucleophilicity is closely related to basicity the knowledge of predicted nucleophilicity can be very important in fixation and similar process. This means calculation and prediction methods can safely be applied.
Acknowledgements
This work was supported by the Scientific and Technological Research Council of Turkey (TBAG-HD 101T224).
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