The molecular geometry of compounds of the series (CH3)nSi(NCX)4-n, (where n 0, 1, 2, 3 X S, O) were investigated with the objective of determining the magnitudes of the SiNC angles. Measurement of the infrared spectra and dipole moments were carried out. The infrared spectra unambiguously suggest linearity, and this is supported by dipole moment calculations. The deviation from linearity observed by electron diffraction is a consequence of shrinkage effects δ(SiNCX) resulting from low frequency, large amplitude vibrations. From the dipole moment values it is concluded that the N-Si-N angle in the di- and trifunctional isothiocyanates is larger than the tetrahedral angle. The structural differences between the silicon and carbon compounds can be attributed to (dp)π bonding in the former.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry