Two-electron transfer catalysis of carbon monoxide exchange 1 with a ligand in hexacarbonyldi-iron compounds [(µ-RS) 2 Fe 2 (CO) 6 ]

Two-electron reduction of [(µ-RS)2Fe2(CO)6](R = alkyl) leads to labile dianionic species which lose CO and decay or, in the presence of a ligand (L) such as P(OMe)3, are involved in a chain reaction affording successively [(µ-RS)2Fe2(CO)5L] and [(µ-RS)2Fe2(CO)4L2].