Preparation and Characterization of the Triflate Complex [Cp*(dppe)FeOSO 2 CF 3 ]: A Convenient Access to Labile Five‐ and Six‐Coordinate Iron(I) and Iron(II) Complexes

Treatment of the iron hydride [Cp*(dppe)FeH] ( 1 ) with methyl triflate (CH 3 OSO 2 CF 3 ) yielded the iron triflate adduct [Cp*(dppe)FeOSO 2 CF 3 ] ( 4 , 85 %). In the solid state, the triflate is coordinated at the iron center as shown by XRD (d Fe–O = 2.118(4) Å) and IR spectroscopy (ν SO = 1305 cm –1 ). In solution, 4 is in equilibrium with the 16‐electron species [Cp*(dppe)Fe]OSO 2 CF 3 ( 5(OSO 2 CF 3 ) ), 4 / 5(OSO 2 CF 3 ) = 2:1). The CV of 4 displays two waves ( E 1 = –0.74 V, E 2 = 0.24 V vs. SCE) assigned to the [Cp*(dppe)Fe(I)]/[Cp*(dppe)Fe(II)] + and [Cp*(dppe)Fe(II)] + /[Cp*(dppe)Fe(III)] 2+ redox couples. Reduction of 4 with Cp 2 Co provided the complex [Cp*(dppe)Fe(I)] ( 6 , 95 %) and oxidation of 6 with [Cp 2 Fe]PF 6 gave [Cp*(dppe)Fe]PF 6 ( 5(PF 6 ) , 98 %). XRD established the pseudo‐trigonal bipyramidal geometry for the five‐coordinated cation 5 + . The reactivity of 5(PF 6 ) and 6 toward small molecules (CH 2 Cl 2 , H 2 O, CO, H 2 , N 2 ) is reported.