Thermal investigation of some chelate Ni(II) complexes

Abstract

Several diamine-nickel(II) complexes have been prepared and the kinetic parameters of their decomposition reactions investigated. The complexes undergo a gradual thermal decomposition. First, water is lost, followed by the departure of the diamine ligands. The activation energies for the first deamination decrease in the order Ni(1,2-pd)(3)Cl-2(H2O)(2) = Ni(en)(3)Cl-2(H2O)(2) gt Ni(1,3 -pd)(3)Cl-2(H2O)(2) gt Ni(dieten)(2)Cl-2 (H2O)(2) (en = 1,2-diaminoethane; 1,2-pd = 1,2-diaminopropane; 1,3-pd = 1,3-diaminopropane; dieten = 2-diethylaminoethylamine) which is in accordance with the chelate effect. The decomposition of the complexes can be represented by a variety of solid state decomposition models depending on the particular complex, as well as on the stage of the decomposition.