Two oxidation states and four different coordinations of iron in an unusual chloro complex: TG–MS, Raman and Mössbauer spectroscopic investigations of the thermal behaviour

Abstract

Conventional simultaneous thermal analysis, capillary-coupled TG–MS, in situ and ex situ Raman and Mössbauer spectroscopy, as well as chemical analysis have been used for the investigation of the first decomposition step of the mixed valence chloroferrate (dmpipzH 2) 6[Fe(II)Cl 4] 2[Fe(III)Cl 4] 2[Fe(II)Cl 5][Fe(III)Cl 6]. Under argon at ca. 200°C, an almost complete reduction proceeds in a solid state reaction forming Fe(II). It is accompanied by the release of HCl and, to a minor degree, carbon containing species. A multi-phase product with at least two chloroferrate species, coke, and C,H,N-containing polymers is formed. Binuclear iron complexes, such as (dmpipzH) 2[Fe(II) 2Cl 6], and small amounts of (dmpipzH)[Fe(III)Cl 4] have been proposed to be the major and minor component of the product mixture, respectively.