Darstellung und spektroskopische Charakterisierung von Natriumpentacyano(phosphan/phosphit)ferraten(III) / Preparation and Spectroscopic Characterization of Sodium Pentacyano(phosphane/phosphite)ferrates(III)

Abstract Sodium pentacyanoferrates(III) of the type Na2[Fe(CN)5L] (L = phosphane or phosphite) have been prepared from sodium pentacyanoferrates(II), Na3[Fe(CN)5L], by bromine oxidation and characterized by Mössbauer, IR, and electronic spectroscopy. Isomer shifts and quadrupole splittings lie within the range commonly found in low-spin iron(III) complexes. A linear correlation was found between isomer shifts and CN stretching and Fe-CN bending frequencies, respectively. The spectroscopic parameters show that the dπ-dπ back bonding of the Fe-P bonds is synergetically strengthened with increasing σ donor capability of the phosphorus ligands.