Mixed valence eta(6)-arene cobalt(I) and cobalt(II) compound

The first carbonyl free mixed valence cobalt(I)/cobalt(II) compound [2{L2Co(I)(eta(6)-C7H8)}](2+) [Co(II)(2)Cl-6](2-) (1) [L = PhC((NBu)-Bu-t)(2)SiCl] was obtained by the reaction of four equivalents of anhydrous CoCl2 with five equivalents of N-heterocyclic chlorosilylene L. In contrast, the reaction of L with CoBr2 yielded [L2CoBr2] (2). Compound 1 was formed by the cleavage of Co-Cl bonds, the reduction of Co(II) to Co(I) and by the coordination of a toluene molecule. The chlorosilylene (L) functions as a reducing agent as well as a neutral sigma-donor ligand. The toluene molecule coordinates to the Co(I) atom in an eta(6)-fashion.