Abstract
Using the chelating C,C'-bis(silylenyl)-ortho-dicarborane ligand, 1,2-(RSi)(2) -1,2-C(2) B(10) H(10) [R=PhC(NtBu)(2) ], leads to the monoatomic zero-valent Ge complex ("germylone") 3. The redox non-innocent character of the carborane scaffold has a drastic influence on the reactivity of 3 towards reductants and oxidants. Reduction of 3 with one molar equivalent of potassium naphthalenide (KC(10) H(8) ) causes facile oxidation of Ge(0) to Ge(I) along with a two-electron reduction of the C(2) B(10) cluster core and subsequent Ge(I) -Ge(I) coupling to form the dianionic bis(silylene)-supported Ge(2) complex 4. In contrast, oxidation of 3 with one molar equivalent of [Cp(2) Fe][B{C(6) H(3) (CF(3) )(2) }(4) ] as a one-electron oxidant furnishes the dicationic bis(silylene)-supported Ge(2) complex 5. The Ge(0) atom in 3 acts as donor towards GeCl(2) to form the trinuclear mixed-valent Ge(0) →Ge(II) ←Ge(0) complex 6, from which dechlorination with KC(10) H(8) affords the neutral Ge(2) complex 7 as a diradical species.