Detection of radical cations of group 14 element organometallics in alkane solutions using the method of time-resolved magnetic field effect

Abstract

Radical cations of Group 14 element organometallics R₄E and R₃EER₃ (E = Si,Ge,Sn, R = Me,Et) were generated in alkane solutions by X-ray irradiation and studied using the time-resolved magnetic field effect technique. Modeling shows that in alkane solutions the g-factors of Me₄E⁺˙ and Me₃EEMe₃⁺˙ are close to those measured in low temperature matrices. At concentrations of organometallics of about 0.1 M the fast electron self-exchange between radical cations Me₄E⁺˙ (E = Si,Ge) and the corresponding neutrals takes place. In the case of R₃EER₃ the electron self-exchange has not been observed. Short times of phase relaxation (∼10 ns) are found for all the studied radical cations. Possible contributions to relaxation rates are discussed. For solutions of Me₄E a peculiarity manifested as a positive magnetic field effect in strong magnetic field is observed in spin dynamics at short times. This peculiarity is assigned to the radical cations of olefins arising upon radiolysis of an alkane solvent.