Estudo dos complexos de pentacianoferrat(II) por espectroscopia Mossbauer

Abstract

Complexes of pentacianoferrate (II), [ Fe(CN)5Lx ](3+x)-, with several ligands L (L = Adenine, Guanine, Purine, Ceffeine, Etilene Sulphide, Dimeti l Sulphoxide and Amonia) are studied. In order to compare the various ligands, a distribution of the bonding strenght of the ligands with the iron atom is presented. The asymmetry of the relative line intensities of the Mbssbauer spectra of the complex with L = NH3, is shown to be due to the so called texture effect. Using the theoretical model adopted to explain the texture effect,the angle between the electric field gradient and the normal to the absorber plane is determined. Since the interactions between the 3d metal orbitals and a-donors and Tr-receptors ligand orbitals are responsible for the tetragonal distortion (Dt), a linear correlation between the isomer shift and Dt is proposed. Through this correlation the parameters Dt for various ligands is determined.