Solvent and structural effects on the UV absorption spectra of N-(substituted phenyl)-2-cyanoacetamides.

UV absorption spectra of N-(substituted phenyl)-2-cyanoacetamides have been recorded in the range 200-400 nm in the set of selected solvents. The solute-solvent interactions were analyzed on the basis of linear solvation energy relationships (LSER) concept proposed by Kamlet and Taft. The effects of substituents on the absorption spectra were interpreted by correlation of absorption frequencies with Hammett substituent constant, σ. It was found that substituents significantly change the extent of conjugation. Furthermore, the experimental findings were interpreted with the aid of ab initio B3LYP/6-311G(d,p) method. Electronic energies was calculated by the use of 6-311++G(3df,3pd) methods with standard polarized continuum model (PCM) for inclusion of the solvent effect.