Synthesis, Characterization and Stability of the Polymeric Complexes of Zinc (II), Cadmium (II) and Cerium (III) with 1,4-bis (2`-carboxyphenyla-zomethine) phenylene

doi:10.21608/ejchem.2011.1409

Synthesis, Characterization and Stability of the Polymeric Complexes of Zinc (II), Cadmium (II) and Cerium (III) with 1,4-bis (2`-carboxyphenyla-zomethine) phenylene

10.21608/ejchem.2011.1409

Abstract

THE FORMATION and stability of binary Zn 2+, Cd2+ and Ce3+ complexes with 1,4-bis(2`-carboxyphenylazomethine)phenylene
(BCPAP) were studied by potentiometric pH-titrations in 50% (v/v) 1,4 dioxane-water medium [I=0.1M KNO 3], 25°C. Under uniform conditions the dissociation constants of the ligand BCPAP have also been examined. The potentiometric data showed that the metal contents in all complexes are consistent with 1:1 metal: ligand stoichiometry. From the formation curves the stepwise stability constants of binary chelates were determined and the optimal pH conditions for preparing the solid complexes were specified. The synthesized complexes were characterized using elemental analysis, infrared and electronic spectra. The reaction of the bis–bidentate ligand (1,4-bis (2`-carboxyphenylazomethine)phenylene) BCPAP with each of Zn2+, Cd2+ and Ce3+ gives coordination polymers. Thermal stabilities of the various coordination polymers were studied. The isolated coordination polymers were investigated by differential scanning calorimetry (DSC) to determine the glass transition temperature (Tg). The obtained Tg and DSC data, showed the formation of one kind of coordination polymers (homo-coordination polymers). The conductivity of the polychelates were measured both from the solution and electrode side. The surfaces of the samples were examined by scanning electron microscopy (SEM).

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