Molecular structure and vibrational spectra of 4-, 5-, 6-chloroindole

The molecular geometry, IR intensities, harmonic and anharmonic vibrational frequencies of 4-, 5-, 6-chloroindole in the ground state were calculated by DFT/B3LYP level of theory using the 6-31G (d, p) basis set. To give complete and reasonable vibrational assignments, the normal coordinate analysis has been performed for 4-chloroindole, 5-chloroindole and 6-chloroindole. The effect of position of chloro atom on the molecular properties (electron density, dipole moments and energies) of the indole aromatic system is examined on the basis of calculation data for 4-, 5- and 6-chloroindoles.