The electronic effect of XMe3 and CH2XMe3(X = Si, Ge, Sn, or Pb) substituents in organometallic sulphides. A kinetic and photoelectron spectroscopic study

Abstract

For organometallic sulphides p-Me₃XC₆H₄SMe (I), p-Me₃XCH₂C₆H₄ SMe (II), and PhSCH₂XMe₃(III)(X = Si, Ge. Sn, or Pb) the oxidation rates with perbenzoic acid have been measured spectrophotometrically at 25° and compared with the ionization energies obtained by u.v. photoelectron spectroscopy measurements. From the results obtained for sulphides (I), +I, (p→d)_π and hyperconjugative contributions almost cancel out; for series (II) and (III) however the electron-releasing character of the CH₂XMe₃ group confirms the importance of C-metal hyperconjugation. Solvent effects on the oxidation rates of the title compounds have also been studied and are discussed in detail.