Vibrational spectroscopic studies, conformations and ab initio calculations of 1,2‐bis(trifluorosilyl)ethane (SiF3CH2CH2SiF3)

摘要: Infrared spectra of 1,2-bis(trifluorosilyl)ethane (SiF3CH2CH2SiF3) were obtained in the vapour and liquid phases, argon matrices solid phase. Raman compound as a recorded at various temperatures between 293 270 K an apparently crystalline observed. The revealed existence two conformers (anti gauche) vapour, matrix. When was chock-frozen on cold finger 78 annealed to 150 K, certain weak bands vanished crystal. vibrational crystal demonstrated mutual exclusion IR accordance with C2h symmetry. Intensity variations pairs gave ΔH(gauche—anti) = 5.6 ± 0.5 kJ mol−1 liquid, suggesting 85% anti 15% gauche equilibrium room temperature. Annealing experiments indicate that conformer also has lower energy matrices, is low-energy present both have been interpreted, 34 17 tentatively identified. Ab initio density functional theory (DFT) calculations performed giving optimized geometries, infrared intensities anharmonic frequencies for conformers. conformational difference derived CBS-QB3 G3 5 mol−1. Copyright © 2009 John Wiley & Sons, Ltd.