NEW ENTRY TO PIANO -STOOL ELECTRON RICH (PENTAMETHYL CYCLOPENTADIENYL) IRON COMPLEXES

a new route to the electron rich pentamethylcyclopetadienyl iron complexes (n5-c5me5)=cp*) starting from the commercially available dimer [cp*fe(co)2]2 ,is presented. reaction of the dimer with i2 in ch2cl2, affords the mononuclear carbonyl complex cp*fe(co)2i which in turn reacts with bis(diphenylphosphinoethane) in toluene under uv irradiation to give cp*fe(dppe)i. treatment of cp*fe(dppe)i with the neutral ligands l (l = ch3cn, pph3, set2) in the presence of tlpf6 affords the cationic derivatives [cp*fe(dppe)l]pf6 ,while that the reaction with s2(ch2c6h5 )2 in ch3oh yields the thiolate complex [cp*fe(dppe)s-ch2c6h5 ] pf6 .the unusual magnetic properties of these complexes are discussed. extended hückel om calculation confirmed the most electron rich character of the cp*fe(dppe)+ derivatives than their unsustituted cpfe(dppe)+ .electrochemical as well as m？sbauer data are in agree with this