H. Bock et J. Meuret, PHOTOELECTRON-SPECTRA AND MOLECULAR-PROPE RTIES .148. 1ST VERTICAL IONIZATION ENERGIES OF BETA-TRIMETHYL-SUBSTITUTED ETHERS RO-CH(3-N)[SI(CH3)3]N, Journal of organometallic chemistry, 459(1-2), 1993, pp. 43-54
The first vertical ionization energies of dialkylethers are lowered up
to 3 eV (!) by beta-trimethylsilyl substituents and, therefore, furth
er confirm the powerful electron donor effect of -CH3-n[Si(CH3)3]n and
-Si[Si(CH3)3]3 groups. The gas-phase photoelectron spectra are assign
ed based on geometry-optimized MNDO calculations and the substituent e
ffects are discussed in terms of conformationally dependent hyperconju
gative second order perturbations.