Synthesis and Thermal Study of the Barium Complexes with 8-hydroxyquinolinate Derivatives

In this present work, barium ion was reacted with different ligands which are 5,7-dibromo 5,7-dichloro, 7-iodo and 5-chloro-7-iodo-8-hydroxyquinoline, in acetone/ammonium hydroxide medium under constant stirring and the obtained compounds were as follows: (I) Ba(C₉ H₄ ONBr₂ )₂ ]⋅1.5H₂ O; (II) Ba(C₉ H₄ ONCl₂ )(OH)]⋅1H₂ O; (III) Ba(C₉ H₅ ONI)₂ ]⋅1H₂ O and (IV) Ba(C₉ H₄ ONICl)₂ ]⋅5H₂ O, respectively. The compounds were characterized by elemental analysis, infrared absorption spectrum (IR), inductively coupled plasma spectrometry (ICP), simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimeter (DSC). The final residue of the thermal decomposition was characterized as orthorhombic BaBr₂from (I); the intermediate residue, as a mixture of orthorhombic BaCO₃ and BaCl₂ and cubic BaO and the final residue, as a mixture of cubic and tetragonal BaO and orthorhombic BaCl₂ (II); the intermediate residue, as orthorhombic BaCO₃ and as a final residue, a mixture of cubic and tetragonal BaO from (III); and the intermediate residue, as a mixture of orthorhombic BaCO₃ and BaCl₂ and as a final residue, a mixture of cubic and tetragonal BaO and orthorhombic BaCl₂ from (IV). This revised version was published online in July 2006 with corrections to the Cover Date.