ASSOCIATIVE SUBSTITUTION MECHANISMS OF CLUSTERS - THE RELATIONSHIP BETWEEN SITES OF NUCLEOPHILIC-ATTACK AND LEAVING GROUP DISSOCIATION

The associative substitution mechanism of [Fe4S4Cl4](2-) With 4-RC(6)H(4)S(-) involves initial, rapid binding of the thiolate to an iron atom (Fe-a), followed by rate-limiting dissociation of a chloro-ligand; however, the origin of the leaving group changes with the electron-releasing capability of the thiolate and when R = Cl, F, H or Me, the chloro-group at Fe-a is labilised, whereas when R = Me, MeO or NH2 the chloro-group at a remote iron site (Fe-r) is labilised.