Dimerization of Thiophene to Give a Linear S(CH)₈S Fragment with [(C₅Me₅)Rh(C₂H₄)₂]

Cleavage of a CS bond and formation of a CC bond are the crucial reaction steps in the construction of the S(CH)8S bridging ligand in the binuclear complex 1, which is accessible from [(C5Me5)Rh(C2H4)2] and thiophene in refluxing benzene. Compound 1 is not only interesting for its mechanistic and structural aspects, but also in connection with the catalytic hydrosulfuration of fossil fuels.