Ligand-to-Metal Ratio Controlled Assembly of Cobalt Complexes Containing <i>ortho</i>-Carborane Thiolato and Butyl Thiolato Ligands

Treatment of ortho-carborane, n-butyl lithium, sulfur, and CpCo(CO)I2 with differing ratios led to four new compounds [(CpCoS2C2B10H10)(CpCoSC2B10H11)(SC4H9)] (3), [(CpCo)2S2(S2C2B10H10) (SC2B10H10)(SC4H9)] (4), [(CpCo)2Co(SC4H9)6]+[Co(S2C2B10H10)2]− (5), and [(CpCo)2Co(SC2B10H11)(SC4H9)5]+[Co(S2C2B10H10)2]− (6). Compound 3 contains a rhombic Co2(μ2-S)2 core and can be considered as an adduct of the two 16e half-sandwich monomers CpCo(S2C2B10H10) (1) and CpCo(SC4H9)(SC2B10H11). Compound 4 is a trinuclear complex containing a cuboidal [Co3(μ3-S)2(μ-S)2] core, and one cobalt atom is coordinated by six sulfur atoms in a distorted octahedral geometry. Compound 5 consists of a linear-type trinuclear cobalt(III) monocation bridged by six n-butyl thiolato units and a square-planar cobalt(III) monoanion [Co(S2C2B10H10)2]−. However, in 6, one ortho-carborane monothiolato ligand [SC2B10H11]− has replaced one n-butyl thiolato ligand in 5. This leads to a nonlinear arrangement of the three cobalt atoms in the cation and the nonplanar [Co(S2C2B10H10)2]− anion in 6. Interestingly, the treatment of the 16e half-sandwich CpCo(S2C2B10H10) (1) by [N(n-Bu)4]Br afforded the ionic compound 7, [N(n-Bu)4]+[Co(S2C2B10H10)2]−, containing a square-planar anion.