Thermal studies on addition compounds of bis(ethylxathato)nickel(II)

Ni(xanthate)₂, a diamagnetic square planar complex forms 1:1 six-coordinated high-spin paramagnetic adducts with dinitrogen donors in different organic solvents. The thermal studies of these compounds show the loss of trapped solvent(ether) followed by the loss of the addendum leaving behind the parent xanthate complex. In the compounds with 1:3 ratio of Ni(xanthate): dinitrogen donors, the xan^? acts as an anion. The different steps of thermal decomposition in the compounds, Ni(phen)₃xan₂ and Ni(bipy)₃xan₂, can be explained on the basis of the conformational rigidity of the ligands. For the parent compound Ni(xan)₂, its 1:1 and 1:3 adducts as well as the thermal decomposition products (residues) have been analysed by chemical and physical methods. New intermediate complexes with the composition, Ni(phen)₂xan₂, Ni(bipy)S₂ and Ni(bipy)S have been obtained from the decomposition process, leading finally to NiO. The kinetic parameters were calculated using five different methods to check the applicability of these standard methods towards the elucidation of the decomposition mechanism.