Fe(II) and Fe(III) complexes of N-ethyl-N-phenyl dithiocarbamate: electrical conductivity studies and thermal properties

Abstract

The electrical conductivity and thermal properties of Fe complexes in different oxidation states of (II)and (III) have been studied using the compounds Fe (II) bis (N-ethyl-N-phenyl dithiocarbamate), andFe (III) tris (N-ethyl-N-phenyl dithiocarbamate). The thermal properties were studied using a simulta-neous thermal analyser (SDTA). Thermogravimetric studies showed initial loss of the ethyl groups in the200–250◦C range, yielding Fe(S2CNC6H5)n(where n = the oxidation state of the iron) as an intermediateproduct, followed by decomposition to give a constant weight which corresponds to iron sulphide at≈ 275◦C. The impedance spectra were analysed using the non-linear least squares fitting of equivalentcircuit. This models the specific grain interiors conductivity with charge carrier relaxation as representedby the Cole–Cole function, and by the impedance of platinum electrodes. The observed data indicatesthat the conduction in both complexes is ionic in nature. The spikes in the lower frequency range, on theimpedance plots, are recognised as presenting the blocking of pathways because of the ion migration.The dielectric permittivity increased with increase in temperature and decreased with increase in fre-quency. The Arrhenius equation was used to study the effect of temperature on electrical conductivity ofthe complexes and the conductivity activation energy