Reactivity of Two 16e Half-Sandwich Cobalt Complexes Containing 1,2-Dicarba-closo-Dodecaborane-1,2-Dichalcogenolate (E2C2B10H10)2– (E = S, Se) Units toward Triphenylphosphine

Treatment of o -carborane, n -butyllithium, sulfur (or selenium) and MeCpCo(CO)I 2 (or Cp*Co(CO)I 2 ) (Cp* = pentamethylcyclopentadienyl) under argon leads to half-sandwich carborane complex MeCpCo(S 2 C 2 B 10 H 10 ) (I) (or Cp*Co(Se 2 C 2 B 10 H 10 ) ( II )). Complex I reacts with triphenylphosphine to afford addition product MeCpCo(S 2 C 2 B 10 H 10 )(PPh 3 ) ( III ). However, II does not react with triphenylphosphine. Complexes II and III have been characterized by elemental analysis, mass, NMR spectroscopy, IR and X-ray structural analyses (CIF files CCDC nos. 1571705 ( II ) and 1571706 ( III )).