VIBRATIONAL-SPECTRA AND NORMAL MODE ASSIGNMENTS FOR (CH3)3SIN3, (CH3)3SINCO AND (CH3)3SINCS

The i.r. spectra (20-3500 cm-1 of gaseous and solid (CH3)3SiN3, (CH3)3SiNCO and (CH3)3SiNCS have been recorded. The Raman spectra (25-3100 cm-1) of these three compounds in the gaseous (except (CH3)3SiNCS), liquid and solid states have also been recorded. A vibrational assignment is proposed for each molecule. The spectral data for the heavy atom vibrations are consistent with C3v symmetry for the isocyanate and the isothiocyanate and there is good evidence for lower symmetry for the azide. The SiNC bend was observed in the Raman spectrum of gaseous isocyanate at 37 cm-1 with the overtone centered at 84 cm-1. This same mode was observed in the Raman spectrum of the isothiocyanate in the liquid state at ∼45 cm-1. For the azide, this motion was observed in the Raman spectra of both the gaseous and liquid samples at 102 and 111 cm-1, respectively. © 1978.