The reactions of elemental germanium with 3,5-di-tert-butyl-1,2-benzoquinone

Abstract

Germanium powder reacts slowly with 3,5-di-tert-butyl-1,2-benzoquinone (dbbq) in refluxing toluene to give products whose composition depends on the initial mole ratio of the reactants. When Ge ∶ dbbsq = 1 ∶ 2, the solid product is a monoradical + diradical species, but in non-aqueous solvents this converts to a diamagnetic oligomer. Treatment with 2,2′-bipyridine, or monodentate nitrogen donors (= L) gives diamagnetic germanium(IV) derivatives Ge(dbc)₂L₂ (dbc²⁻ = 3,5-di-tert-butylcatecholate dianion). When the initial Ge ∶ dbbq mole ratio = 1 ∶ 3, the product is the diradical Ge(dbbsq˙)₂(dbc). The reaction of Ge and 4 dbbq, or the treatment of GeX₄ (X = Cl, Br) with 4 moles of Na(dbbsq˙), gives a product identified as Ge(dbbsq˙)₂(dbc)(dbbq), but the structure of this compound is unclear. The solid state and solution properties of these unusual compounds are discussed in the light of ¹H NMR and electron spin resonance (ESR) spectroscopy.