The vibrational spectra of norbornene and nadic anhydride

Abstract

The vibrational spectra of norbornene (bicyclo[2,2,1]hept-2-ene) and nadic anhydride (cis-endo-5-norbornene-2,3-dicarboxylic anhydride) have been investigated by infrared, Raman and inelastic neutron scattering spectroscopies and density functional theory (DFT). For norbornene, the five missing fundamentals have been located. In the C–H stretch region, the infrared and Raman spectra synthesised from the DFT calculations are shown to be in poor agreement with the experimental spectra. Visualisation of the C–H stretch modes shows that assignments made on the basis of group frequency correlations are incorrect. Nadic anhydride has not been previously investigated by vibrational spectroscopy. This paper demonstrates that with state-of-the-art inelastic neutron scattering spectra it is possible to successfully analyse complex systems that have not been studied before.