THERMAL-DECOMPOSITION STUDIES OF TRIS(N,N'-DIALKYLDITHIOCARBAMATO)IRON(III) COMPLEXES BY MOSSBAUER-SPECTROSCOPY

A series of complexes of the type [Fe(R'R''NCS2)3] with R' = R'' = CH3 and C2H5; R' = CH3, R'' = C2H5; R' = CH3, R'' = i-C3H7; R'= CH3, R'' = C6H5 and R'NR'' = pyrrolidyl and piperidyl, has been synthesized and their thermal decomposition studied. The complexes have been characterized by elemental analysis, electronic, IR and Mossbauer spectral and magnetic measurements. Mossbauer spectra of all the complexes at room temperature exhibit a quadrupole doublet with delta = 0.58-0.68 mm s-1 (w.r. to SNP) and DELTAE(Q) = 0.25-0.70 mm s-1, except for pyrrolidyl and piperidyl complexes which exhibit delta = 0.93 and 0.42 mm s-1, respectively. Thermal decomposition behaviour can be divided into three groups of volatile, non-volatile and those yielding metal sulphides/oxides. An attempt has been made to identify intermediate and final products. Mossbauer spectra of the complexes at > 650-degrees-C exhibit six line patterns with H(eff) = 515 +/- 5 kOe, suggesting the formation of alpha-Fe2O3 in all cases.