Ab initio calculations and vibrational spectra of 5-methoxy indole

Polarized Fourier transformed infrared (FT-IR) spectra of partially oriented 5-methoxy indole crystals and the Raman spectra of the melt and polycrystalline 5-methoxy indole are reported. Solvent effect study on the IR spectrum of 5-methoxy indole is also reported. Observed frequencies for normal modes are compared with those calculated from normal mode coordinate analysis carried out on the basis of ab initio force fields using the 3-21G basis set theoretical optimized geometry. The manifestations of the NH-π interaction in the vibrational spectra are discussed.