Magnetic and Mössbauer investigations of NN-disubstituted bis(dithiocarbamato)iron(II) complexes

Abstract

Bis(dithiocarbamato)iron(II) complexes [{Fe(S2CNR2)2}n] have been found to form two classes. With R = Et, Prn, or Bun, isomorphous relations with copper(II) complexes of known structure show that the complexes are dimers containing square-pyramidal iron. Considerable antiferromagnetic interaction is present, and the chemical isomer shifts and reflectance spectra are characteristic of high-spin FeII. Very large quadrupole splittings (ca. 4.2 mm s–1) have been obtained. These complexes exhibit clean quadrupole doublets at 4.2 K consistent with diamagnetic ground states as expected for dimers. This is confirmed by the behaviour in an applied field. When R = Me or R2= C4H8 no isomorphous relations have been found, but polymeric octahedral structures are suggested by the smaller quadrupole splitting (ca. 2.5 mm s–1), weaker antiferromagnetism, reflectance spectra indicating less distortion, and the complex magnetic-hyperfine splitting at 4.2 K in zero field.