The dissociation constants of azosulfonamide derivatives of rhodanine have been determined potentiometrically in 0.1 M-KCl and 10 vol. % DMF-water mixture. The data are discussed in terms of electron nature of the substituents and of the change in temperature. The pK1 H values have been found to increase with increasing electron-donating nature of the substituents. The evaluated thermodynamic parameters (delatG, deltaH, and deltaS) indicated that the dissociation processes are not spontaneous; they are endothermic and entropically unfavourable.
The dissociation constant of 4-(4-acetophenyl)hydrazono-3-methyl-1-phenyl-2-pyrazolin-5-one (AHMPP) has been determined potentiometrically in 0.1 M KCl and 50% (v/v) ethanol-water mixture. Also, the stepwise stability constants of the formed complexes of Mn2+, Co2+, Ni2+, Cu2+, Zn2+, La3+, Ce3+, UO2+2 and Th4+ with AHMPP have been determined. The stability of the formed complexes follow the sequence: Th4+ UO2+2 Ce3+ La3+ Mn2+ Co2+ Ni2+ Cu2+ Zn2+ The thermodynamic parameters (deltaG, delta H and deltaS) for AHPP and its complexes were evaluated and discussed. The dissociation process is nonspontaneous, endothermic and entropically unfavourable. The formation of the metal complexes has been found to be spontaneous, exothermic or endothermic (depends on the metal) and entropically favourable. The stoichiometries of these complexes were determined conductometrically indicating the formation of 1:1 and 1:2 (etal:ligand) complexes.
Metal complexes of copper, nickel, cobalt, uranyl have been prepared and characterized by chamical and thermal analyses, molar conductivity, magnetic susceptibility measurements, and infrared, electronic and EPR spectra. The visible and EPR spectra indicated that the Cu(II) complex has a tetragonal geometry.
The synthesis of several new coordination compounds of Copper(II), nickel(II), cobalt(II), manganese(II), iron(II), tin(II), mercuryl(II), dioxouranium(VI) and iron(III) are described. The ligands and the complexes have been characterized by elemntal analyses, together with magnetic susceptibility measurements.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.