Gas phase basicity of silanaldehydes and silanones

Henri E. Audier (1) , J. Fossey (1) , J.P. Denhez (1) , J.-P. Jacquet (1) , Philippe Mourgues (1)

1 DCMR - Laboratoire des mécanismes réactionnels

Gas basicities (GBs) and proton affinities (PAs) of CH3SiH=O, CH3CH2SiH=O, (CH3)2Si=O (CH3CH2)2Si=O, were determined by using the kinetic method as well as calculations. From experiment, GB of these molecules were respectively measured to be 203.3, 206.3, 213.4 and 218.0kcalmol-1. The precision is estimated to be 0.5kcalmol-1. Calculations are in excellent agreement with experiment. GB and PA of the R1R2Si=O compounds are far above those of their counterparts R1R2C=O, containing exclusively carbon. The difference lies between 25 and 30kcalmol-1 and slightly decreases as the substitution degree of silicon increases. This behavior strongly contrasts with that of silanols or silanamines whose GB and PA are close to those of the corresponding alcohols or amines. This can be explained by the high ΔHf of neutral low coordinate molecules containing silicon. © 2003 Elsevier Science B.V. All rights reserved.

Henri E. Audier, J. Fossey, J.P. Denhez, J.-P. Jacquet, Philippe Mourgues. Gas phase basicity of silanaldehydes and silanones. International Journal of Mass Spectrometry, 2003, 227 (3), pp.381-389. ⟨10.1016/S1387-3806(03)00089-7⟩. ⟨hal-00917375⟩