Thermal and spectral studies of binary complexes of cyanodithioformate with transition metal ions

Binary complexes of the type [M(S2CCN)2] (M=Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) have been synthesised from alcoholic solutions. They have been characterised using elemental analyses, IR, UV–VIS spectroscopy, magnetic susceptibility measurement and solution conductance data. In thermogravimetry (TG) studies, all these complexes exhibit a prominent weight loss step between 100 and 330 °C under a N2 atmosphere. Besides, a second weight loss step has also been observed beyond 800° C for the Mn2+, Fe2+ and Co2+ complexes, between 400 and 600 °C for Zn2+ complex and beyond 380 °C for Cu2+ complex. Broad differential thermal analysis (DTA) endotherms are observed corresponding to these weight loss steps. The first weight loss in the TG scan of the complexes follows a deceleratiory α–time curve with D3 mechanism for all complexes. The activation energy (Ea) for the thermal decomposition varies between 43 and 115 kJ/mol and removal of CS2 and/or CS have been suggested. Various decomposition parameters have been calculated.