Studies on stabilities of 6-(5'-8'-hydroxyquinolinic)methylene-1,4,8,11-tetraazacyclo tetradecane-5,7-dione, 5-substituted 1,10-phenanthroline-copper(II) with Cu²⁺ or Co²⁺ binuclear mixed-coordinated systems

Abstract

C-functionalized dioxotetraamine 6-(5'-8'-hydroxyquinolinic)methylene-1,4,8,11-tetraazacyclo tetradecane-5,7-dione ligand, containing two independent chelating groups, L has been synthesized and characterized by elemental analysis, IR, mass spectra and ¹H NMR spectra. The <i>p</i>H titration has been performed to study the stabilities of L-5-R-1,10-phenanthroline-Cu(II) with proton, copper(II) and cobalt(II). The results show that for Cu²⁺

and Co²⁺, 8-hydroxyquinoline is a stronger chelating reagent than dioxotetraamine macrocycles. Using molecular mechanics (MM⁺) calculation, the stability of ternary mixed system on Co(II)-L-5-substituted-1, 10-phenanthroline-Cu(II) and Cu(II )-L-5- substituted-1, 10 -phenanthroline Cu(II), compared with the coordination ability for different coordination sites and for different metal ions [Co(II) and Cu(II)) at same coordination site have been

studied.