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Competitive Spectrophotometrc Study of Complexation of Dibenzopyridino-18-crown-6 with Ca2+, Sr2+, and Ba2+ in Binary Dimethylsulphoxide-Acetonitrile Solutions

Zolgharnein J., Zahirredini F., Azimi G.

Polish Journal of Chemistry

2003

Vol. 77 / nr 7

813-820

The complexation of dibenzopyridino-18-crown-6 (DBPY18C6) with Ca2+, Sr2+ and Ba2+ has been studied in binary dimethylsulphoxide - acetonitrile mixtures at 25_C by a competitive spectrophotometric technique, using murexide as a metal ion indicator. Stoichiometry and stability of the resulting complexes were evaluated by KINFIT program. The stability of 1:1 complexes prepared were found strongly solvent dependent. There is an inverse linear relationship between log Kf and mole fraction of dimethylsulphoxide (DMSO) in the solvent. In all these solvents the increase of %AN increases the stability of DBPY18C6 complexes with alkaline earth cations in the sequence Ba2+ > Sr2+ > Ca2+.

Solvent extraction of inorganic and organic cations by octakis-O-diphenoxyphosphoryl-tetramethylcalix[4]resorcinarene

Taraszewska J., Koźbiał M.

Chemia Analityczna

2002

Vol. 47, No. 3

409-418

Extraction of alkali metal, alkaline-earth metal Mg(II), Ca(II) cations and ammonium picra-tes as well as of Eu(IIl) and La(IlI) nitrates by complexation with octakis-O-diphenoxyphos-phoryl-tetramethylcalix[4] resorcinarene was studied by a liquid-liquid extraction from aqueous phase into chloroform. Extraction percentages (E%), stoichiometry and overall extraction constants (Kex) were determined. E% increased in the order lanthanum, europium >alka-line earth cations >ammonium cations>alkali cations. The stoichiometry of the complexes was 1:1. Kex increased with the increase of cation charge.

Zbadano ekstrakcję z fazy wodnej pikrynianów metali alkalicznych, ziem alkalicznych Mg(II), Ca(II) i alkiloammoniowych oraz azotanów Eu(III) i La(lII) w wyniku komplekso-wania roztworem oktakis- difenoksyfosforylo-tetrametylokaliks[4]rezorcynarenu w chloroformie. Wyznaczono procenty ekstrakcj i (E%), stechiometrie, i stale ekstrakcj i (Kex). E% wzrastał w kolejności, lantan, europ >kationy metali ziem alkalicznych >kationy alkiloamo-niowe >kationy metali alkalicznych. Stechiometria kompleksów była1: 1. Kex wzrastała ze wzrostem ładunku kationu