title: Isolation and structural and electronic characterization of salts of the decamethylferrocene dication.
abstract: Ferrocene and its decamethyl derivative [Cp*2Fe] are the most common standards for nonaqueous electrochemical investigations because of their well-defined and only mildly solvent-dependent reversible Fe(II)/Fe(III) redox couple. Higher oxidation states have only rarely been studied. We report the isolation and crystallographic and spectroscopic characterization of surprisingly stable Fe(IV) salts of the [Cp*2Fe](2+) dication, produced by oxidation of [Cp*2Fe] with AsF5, SbF5, or ReF6 in neat sulfur dioxide as well as [XeF](Sb2F11) in neat hydrogen fluoride. The Sb2F11(-) salt exhibits a metallocene with the expected mutually parallel arrangements of the Cp* rings, whereas the As2F11(-), AsF6(-), SbF6(-), and ReF6(-) salts manifest tilt angles ranging from 4° to 17°. Both (57)Fe Mössbauer spectroscopy and superconducting quantum interference device magnetization studies reveal identical d-orbital splitting with an S = 1, (3)E ground state based on the 3d electronic configuration e2g (3)a1g (1) of all [Cp*2Fe](2+) salts.
authors: Inorganic Chemistry, Institute of Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany. moritz.malischewski@fu-berlin.de karsten.meyer@fau.de.
authors: M
authors: M
authors: Malischewski
authors: Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg, 91058 Erlangen, Germany.
authors: M
authors: M
authors: Adelhardt
authors: Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg, 91058 Erlangen, Germany.
authors: J
authors: J
authors: Sutter
authors: Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg, 91058 Erlangen, Germany. moritz.malischewski@fu-berlin.de karsten.meyer@fau.de.
authors: K
authors: K
authors: Meyer
authors: Inorganic Chemistry, Institute of Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany.
authors: K
authors: K
authors: Seppelt