Microwave, infrared and Raman spectra, adjusted r0 structural parameters, conformational stability, and vibrational assignment of cyclopropylfluorosilane

Abstract

FT-microwave, infrared spectra of gas and Raman spectra of liquid for cyclopropylfluorosilane, c-C3H5SiH2F have been recorded. 51 transitions for the 28Si, 29Si, and 30Si isotopomers have been assigned for the gauche conformer. Enthalpy differences in xenon solution by variable temperature infrared spectra between the more stable gauche and lesser stable cis form gave 109±9cm−1. From the microwave rotational constants for the three isotopomers (28Si, 29Si, 30Si) combined with structural parameters predicted from MP2(full)/6-311+G(d,p) calculations, adjusted r0 structural parameters were obtained for the gauche conformer. The heavy atom distances (Å): Si–C2=1.836(3); C2–C4=1.525(3); C2–C5=1.519(3); C4–C5=1.494(3); Si–F=1.594(3) and angles (°): ∠CSiF=111.2(5); ∠SiC2C4=117.5(5); ∠SiC2C5=119.2(5). To support the vibrational assignments, MP2(full)/6-31G(d) calculations were carried out. Results are discussed and compared to the corresponding properties of some similar molecules.