Microwave, r0 Structural Parameters, Conformational Stability, and Vibrational Assignment of (Chloromethyl)fluorosilane

The FT-microwave spectrum (6.5-26 GHz) of (chloromethyl)fluorosilane (ClCH2-SiH2F) has been recorded and 250 transitions for the parent species along with C-13, Cl-37, Si-29, and Si-30 isotopologues have been assigned for trans conformer. Infrared spectra (3100 to 400 cm(-1)) of gas, solid, and the variable temperature (-100 to -60 degrees C) studies of the infrared spectra of the sample dissolved in xenon have been recorded. Additionally, the variable temperature (-153 to -133 degrees C) studies of the Raman spectra of the sample dissolved in krypton have been recorded. The enthalpy difference between the trans and gauche conformers in xenon solutions has been determined to be 109 +/- 15 cm(-1) (1.47 +/- 0.16 kJ mol(-1), and in krypton solution, the enthalpy difference has been determined to be 97 +/- 16 cm(-1) (1.16 +/- 0.19 kJ mol(-1)) with the trans conformer as the more stable form. Approximately 46 +/- 2% of the trans form is present at ambient temperature. By utilizing the microwave rotational constants of five isotopologues for trans and the structural parameters predicted from MP2(full)/6-311+G(d,p) calculations, adjusted r(0) parameters have been obtained for trans conformer. The r(0) structural parameter values for the trans form are for the heavy atom distances (angstrom): Si-F = 1.608 (3); C-Cl = 1.771 (3); Si-C = 1.884 (3); and angles (deg): angle FSiC = 108.9 (5); angle ClCSi = 104.9 (5). The results are discussed and compared to some related molecules.