Piano-stool iron complexes containing theC-C unsaturated IMes or saturated H
2-IMes ligand arereadily synthesized from [CpFe(CO)
2(I)]. Substitution ofthe iodide ligand affords the cationic species [CpFe(CO)
2(L)][[I] (
1a+I-) and (
1b+I-) (
a, L = IMes,
b, L = H
2-IMes), subsequent decarbonylation of which yields theneutral iodo derivatives
2a,
b. Cyclic voltammetry studiesof
2a,
b show a reversible one-electron oxidation to thecorresponding 17-electron radical cation. The mono(acetonitrile) complexes
3a,
b are obtained from UVirradiation of
1a,b+PF6- in CH
3CN, but displacementof the second CO ligand is inhibited by strong metal-CO
-back-donation.