Synthesis and structure of iron (III) and iron (II) complexes in S₄P₂ environment created by diethyldithiocarbamate and 1,2-bis(diphenylphosphino)ethane chelation: Investigation of the electronic structure of the complexes by Mössbauer and magnetic studies

Tanmay K. Jana (1) , Dhurjati P. Kumar (1) , Rabindranath Pradhan (1, 2) , Subhajit Dinda (1) , Pradip N. Ghosh (1) , Corine Simmonet (3) , Jérome Marrot (3) , Inhar Imaz (2) , Alain Wattiaux (2) , Jean-Pascal Sutter (4) , Francis Secheresse (3) , Ramgopal Bhattacharyya (1)

1 Department of Chemistry
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 ILV - Institut Lavoisier de Versailles
4 LCC - Laboratoire de chimie de coordination

Iron (II) and iron (III) complexes, [FeII(DEDTC)2(dppe)] · CH2Cl2 (1), [FeII(ETXANT)2(dppe)] (2) (DEDTC = diethyldithiocarbamate, ETXANT = ethyl xanthate, dppe = 1,2-bis (diphenylphosphino) ethane), and [FeIII(DEDTC)2(dppe)] [FeIIICl4] (3) have been synthesized and characterized. Since 3 contains two magnetic centers, an anion metathesis reaction has been conducted to replace the tetrahedral FeCl4− by a non-magnetic BPh4− ion producing [FeIII(DEDTC)2(dppe)]BPh4 (4) for the sake of unequivocal understanding of the magnetic behavior of the cation of 3. With the similar end in view, the well-known FeCl4− ion, the counter anion of 3, is trapped as PPh4[FeIIICl4] (5) and its magnetic property from 298 to 2 K has been studied. Besides the spectroscopic (IR, UV–Vis, NMR, EPR, Mass and XPS) characterization of the appropriate compounds, especially 2, others viz. 1, 3 and 4 have been structurally characterized by X-ray crystallography. While FeII complexes, 1 and 2, are diamagnetic, the FeIII systems, namely the cations of 3, and 4 behave as low-spin (S = 1/2) paramagnetic species from 298 to 50 K. Below 50 K 3 shows gradual increase of χMT up to 2 K suggesting ferromagnetic behavior while 4 exhibits gradual decrease of magnetic moment from 60 to 2 K, indicating the occurrence of weak antiferromagnetic interaction. These conclusions are supported by the Mössbauer studies of 3 and 4. The Mössbauer pattern of 1 exhibits a doublet site for diamagnetic (2–400 K) FeII. The compounds 1, 2 and 4 encompass interesting cyclic voltammetric responses involving FeII, FeIII and FeIV.

Mots clés: Iron complexes; Sulfur and phosphorous donors; Crystal structure; Mössbauer spectra; Magnetic studies; Cyclic voltammetry

Domaines: Matériaux

Tanmay K. Jana, Dhurjati P. Kumar, Rabindranath Pradhan, Subhajit Dinda, Pradip N. Ghosh, et al.. Synthesis and structure of iron (III) and iron (II) complexes in S₄P₂ environment created by diethyldithiocarbamate and 1,2-bis(diphenylphosphino)ethane chelation: Investigation of the electronic structure of the complexes by Mössbauer and magnetic studies. Inorganica Chimica Acta, 2009, 362 (10), pp.3583-3594. ⟨10.1016/j.ica.2009.04.007⟩. ⟨hal-00528913⟩