Sensitivity of the C-N Vibration to Solvation in Dicyanobenzenes: A DFT Study

Using DFT calculations, we have studied the C-N vibration of dicyanobenzenes in different solvents. The effects of solvent polarity and hydrogen bonding were evaluated. The frequency is decreased by 4 cm–1 when the solvent polarity increases. In the current study, the red shift due to the solvent polarity was underestimated by PCM. For hydrogen bonding, the frequency is increased by 10 cm–1 because of the charge transfer from the lone pair of nitrogen in C≡N to water, which slightly increases the bond strength of C-N. The C-N vibration of dicyanobenzenes is calculated to be sensitive to solvation.