FT-IR, FT-Raman spectra and ab initio HF and DFT calculations of 2-nitro- and 4-nitrobenzaldehydes

Combined experimental and theoretical studies on molecular and vibrational structure of 2-nitrobenzaldehyde and 4-nitrobenzaldehydes are reported. The Fourier transform infrared and Fourier transform Raman spectra of 2NB and 4NB has been recorded in the solid phase. The optimized geometry has been calculated by HF and B3LYP methods with 6-311++G(d,p) basis set. The harmonic vibrational frequencies of the title compounds have been performed at the same level of theories. The scaled theoretical wave numbers show very good agreement with the experimental values. The thermodynamic functions of the title compounds have also been computed at HF/6-311++G(d,p) and B3LYP/6311++G(d,p) levels of theory. A detailed interpretation of the infrared and Raman spectra of 2NB and 4NB is reported. The theoretical FT-IR spectra of the title molecules have also been constructed.