Organometallic peroxy radicals. Part II. A kinetic electron spin resonance study of some organogermylperoxy radicals

Abstract

Trimethylgermylperoxy and triphenylgermylperoxy have been prepared and their kinetic behaviour investigated by electron spin resonance techniques. At low temperatures (< −50 °C) these radicals exist in equilibrium with the tetroxide. The thermodynamic parameters for this equilibrium (−ΔH0 ≈ 11.5 kcal mol−1 and −ΔS0 ≈ 26.5 cal deg−1 mol−1) are the same, within experimental error, for both radicals. Above −50 °C (CH3)3GeO2 and (C6H5)3GeO2 decay irreversibly by a unimolecular process. (C6H5)3GeO2 is slightly less stable than (CH3)3GeO2 although both radicals appear to fit an Arrhenius equation of the approximate form log (kepr1/s−1) ≈ 5 − 6/θ where θ = 2.303RT kcal mol−1.