A reaction of complexes CoCl(dppe) (dppe is the 1,2-bis(diphenylphosphino)ethane) or CoCl(dppp) (dppp is the 1,3-bis(diphenylphosphino)propane) with [K][7,8- nido-CBH] upon reflux in benzene led to the mixed ligand closo-cobaltacarboranes [3,3-(PhP(CH)PPh)-3-Cl- closo-3,1,2-CoCBH] ( n = 2 and 3, respectively) in moderate yields (34 and 16%). The structure of the 18-electron complexes in solution and the solid state was studied by NMR and IR spectroscopy, the structure in the case of the closo-complex with dppe-ligand was confirmed by X-ray crystallography. [ABSTRACT FROM AUTHOR]