Structure and vibrational frequencies of 6-chloro-8-thia-1,4-epoxybicyclo[4.3.0]non-2-ene: density functional theory study

The Fourier transform infrared (FT-IR) spectrum of 6-chloro-8-thia-1,4-epoxybicyclo4.3.0]non-2-ene has been recorded in the region 4000–525 cm^? 1. The optimised geometry, frequency and intensity of the vibrational bands of the title compound have been calculated using the ab initio Hartree–Fock and the density functional theory method with 6-31G(d,p) and 6-311G(d,p) basis set levels. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR spectrum. The observed and the calculated frequencies are found to be in good agreement. The theoretical vibrational spectrum of the title compound were interpreted by means of potential energy distributions using VEDA 4 program.