New entry to piano -stool electron rich (pentamethyl cyclopentadienyl) iron complexes

Abstract

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 TIPF6 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 Mösbauer data are in agree with this.