The polymeric nature of Bis(acetylacetonato)-, Bis(trifluoroacetylacetonato)-, Bis(hexafluoroacetylacetonato)-, and Bis(2,2,6,6-tetramethylheptane-3,5-dionato)-iron(II)

Abstract

The preparations of bis(acetylacetonato)iron(II), Fe aca₂; bis(trifluoroacetylacetonato)iron(II), Fe tfa₂; bis(hexafluoroacetylacetonato)iron(II), Fe hfa₂; and bis(2,2,6,6- tetramethylheptane-3,5-dionato)iron(II), Fe dpm₂, are described. Cryoscopic and ebullioscopic molecular weight measurements show that these complexes are monomeric in dilute benzene solutions. Fe aca₂ approaches a hexamer at 5° in concentrated benzene solutions, with Fe tfa₂ and Fe hfa₂ having maximum polymerization numbers of 1.63 and 1.5 respectively. Visible absorption spectra support the molecular weight data. Powder photographs show that Fe dpm₂ is a tetrahedral monomer and that Fe tfa₂ and Fe hfa₂ are isomorphous.