Vibrational Spectra and Stable Conformations of Methyl 6-Methoxy-2,3,4,9-Tetrahydro-1H-1,4-Ethanocarbazole-3-Carboxylate

A study is performed of IR absorption and Raman spectra of methyl 6-methoxy-2,3,4,9-tetrahydro-1H-1,4-ethanocarbazole-3-carboxylate. Optimized structures and the harmonic force fields of stable conformers are calculated using the density functional theory (the B3LYP, M062X, and BVP86 functionals combined with basis sets of different completeness). A detailed explanation of the spectra is proposed based on calculations, and the characteristic frequencies of the most stable forms of a given compound are identified. The theoretical spectra are analyzed relative to experimental data.