Synthesis, characterization and thermal studies of nickel (II), copper (II), zinc (II) and cadmium (II) complexes with some mixed ligands

Dichloro - (DCA) and trichloroacetate (TCA) -cyclic ligand morpholine (Morp h)/thiomorpholine (Tmorph)/methylmorpholine (Mmorph)/ dimethyl-piperazine ( DMP) complexes of nickel (II), copper (II), zinc (II) and cadmium (II) with the compositions [Ni(tmorph)(2) (DCA)(2)], [Ni(tmorph)(2) (TCA)(2)]. 2H(2) O, [Cu (DMP)(2) (TCA)(2)], [ML2X2]. nH(2)O where M = Zn-II or Cd-II, L = Mo rph, DMP or tmorph and X = DCA or TCA and n = O except in case of [Cd(Morph )(2) (TCA)(2)] where n = 1 have been synthesised. Some intermediate complex es have been isolated by temperature arrest technique (pyrolysis) and chara cterised. Configurational and conformational changes have been studied by e lemental analyses. IR and electronic spectra, magnetic moment data (in the case of Ni(II) and Cu(II) complexes) and thermal analysis. E-a*, Delta H an d Delta S for the decomposition reaction of these complexes are evaluated a nd the stability of the complexes with respect to activation energy has als o been compared. A linear correlation has been found between E-a* and Delta S for the decomposition of the complexes.