Competitive potentiometric study of the thermodynamics of complexation of some transition and heavy metal ions with dibenzopyridino-18-crown-6 in methanol using Ag+ ion as a probe
M. Shamsipur et J. Zolgharnein, Competitive potentiometric study of the thermodynamics of complexation of some transition and heavy metal ions with dibenzopyridino-18-crown-6 in methanol using Ag+ ion as a probe, J INCL P MA, 40(1-2), 2001, pp. 41-44
Citations number
25
Categorie Soggetti
Chemistry
Journal title
JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
The complexation of dibenzopyridino-18-crown-6 with some transition and hea
vy metal ions in methanol solution at various temperatures was studied by a
competitive potentiometric method using a Ag+/Ag electrode system. The sto
ichiometry and stability of the resulting complexes were computed by the MI
NIQUAD program. The stability of the resulting complexes varied in the orde
r Ag+ > Pb2+ > Tl+ > Cu2+ > Cd2+ > Zn2+. The enthalpy and entropy of the re
sulting 1:1 complexes were evaluated from the temperature dependence of the
stability constants. The complexes of all cations were enthalpy-stabilized
but entropy-destabilized, except for Ag+ and Pb2+ ions, which were also en
tropy- stabilized.