M÷ssbauer studies in transition metal chemistry. I. Compounds of iron with Dithioacetylacetone (Pentane-2,4-dithione)

Abstract

The temperature dependence of the Mossbauer spectra of some iron- containing compounds of dithioacetylacetone are reported between 4 and 293 K.     The quadrupole splitting ΔE_q of [Fe(SacSac)₃] is larger than usually observed for low-spin six-coordinated iron(III) and is ascribed to the lifting of orbital degeneracy of the ²T₂ ground state by small axial and rhombic distortions.     The unsubstituted and phenyl-substituted dithiolium salts of [FeCl₄]^2- exhibit strongly temperature-dependent quadrupole splittings, which arise directly from the lifting of the orbital degeneracy of the ⁵E ground state due to distortion of the [FeCl₄]^2- tetrahedron.