Improved synthesis and electronic structure of the 19-and 20-electron complexes [Fe(η6-C6Me6)2]n+, n= 1,0

The 19- and 20-electron complexes [Fe(η6-C6Me6)2]n(n= 1,0) are best synthesized by Na/Hg reduction of [Fe(η6-C6Me6)2]2[PF6–]2; the extremely negative value of the quadrupole splitting for [Fe(η6-C6Me6)2], comparison of Mossbauer parameters of [Fe(η6-C6Me6)2]n+(n= 0,1,2), and the temperature dependence of the quadrupole splitting for [Fe(η6-C6Me6)2]+ indicate high metal character for the antibonding e1* orbital and rhombic distortion of the Jahn–Teller-active FeI complex.