Unexpected fragmentation of phenyldithiobenzoate, formation and X-ray structure of [μ,η2(S,S)-1,2-(dithio)-1,2-(diphenylethylene)] diiron hexacarbonyl complex
Résumé
The reaction of Fe-2(CO)(9) with phenyldithiobenzoate PhCS2Ph 1 afforded four colored compounds: [(mu-eta(3)(C,S,S)PhCS2Ph)]Fe-2(CO)(6) 2, (mu-S)(2)Fe-3(CO)(9) 3, (mu-SPh)(2)Fe-2(CO)(6) 4 and [mu-eta(2)(S,S)][PhC(S) C(S)Ph]Fe-2(CO)(6) 5. Complex 5 was characterized by X-ray crystallography. The formation of complexes 4 and 5 was unexpected since it involved a fragmentation of the organic ligand 1 during its reaction with Fe-2(CO)(9). The electrochemical studies of 1, complexes 2 and 3 were undertaken in order to get information about the chemical behaviors of the intermediates generated by electron transfer. The results of cyclic voltammetry studies of 2 and 1 suggested that the reaction of 1 with Fe-2(CO)(9) involved two competitive reactions: (i) a thermal reaction which led to the expected compounds 2 and 3 and (ii) an electron transfer reaction involving a fragmentation of starting ligand 1 led to the unexpected complex 5. The required electrons may be provided by iron during the thermal decay of complexes 2 or 3 or Fe-2(CO)(9).