FT-IR, FT-Raman spectra and ab-initio DFT vibrational analysis of 2-chloro-5-aminopyridine

Abstract

The FT-IR and FT-Raman spectra of 2-chloro-5-aminopyridine (CAP) have been recorded in the region 4000-400 cm -1 and 3500-100 cm -1 , respectively. The optimized geometry, frequency and intensity of the vibrational bands of CAP were obtained by the ab- initio and DFT levels of theory with complete relaxation in the potential energy surface using 6-31G(d,p) and 6-311+G(2df,2p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated potential energy distribution (PED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed bar type spectrograms.