Photoelectron spectra and molecular properties CXXII. The low first ionization energies of the β-trimethylsilyl substituted sulfides (H3C)3SiH2CSCH2Si(CH3)3 and ((H3C)3Si)3CSCH3 and their rationalization

Article abstract of DOI:10.1016/0022-328X(90)87004-W

The rather low first vertical ionization energies of bis(trimethylsilylmethyl)sulfide, IE₁ ^V = 8.04 eV, and tris(trimethylsilyl)methylmethyl sulfide, IE₁ ^V = 7.66 eV, are compared with those of other alkyl, silylalkyl and silylsulfides and shown further to confirm the small influence of α-trimethylsilyl groups and of the very large donor effect of β-trimethylsilyl substituents in the ground state of radical cations.The overall 2.8 eV (!) lowering of the sulfur ? lone pair ionization and of the individual, mostly non-additive, substituent effects, are rationalized in terms of a qualitative approach based on the electron distribution in the ground state of the neutral molecules.