Usage of (C5R5)Co(CO)I2 (R = H, Me) for the synthesis of 12-vertex closo-cobaltacarboranes. Unexpected formation of 10-{CpCo(C5H4)}-7,8-Me2-7,8-nido-C2B9H9

A series of 12-vertex closo-cobaltacarboranes 1,2-Rʹ2-3-(C5R5)-3,1,2-CoC2B9H9 (1a: R = Rʹ = H; 1b: R = Me, Rʹ = H; 2a: R = H, Rʹ = Me; 2b: R = Rʹ = Me) were synthesized by reactions of the carbonyl cobalt complexes (C5R5)Co(CO)I2 with Tl[Tl(η-7,8-Rʹ2-7,8-C2B9H9)]. The reaction of CpCo(CO)I2 with Tl[Tl(η-7,8-Me2-7,8-C2B9H9)] is accompanied by side formation of the novel charge-compensated nido-carborane 10-{CpCo(C5H4)}-7,8-Me2-7,8-nido-C2B9H9 (3) in 19% yield. The structures of 2a,b and 3 were determined by X-ray diffraction. © 2018