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Cyclic Voltammetric Study of the Complexation of Pb2+ Ions by Dibenzopyridino-18-crown-6 in Some Nitriles

Chojnacka-Kalinowska G., Kalinowski M.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 9

1605-1610

EN

A cyclic voltammetric study of the interaction of Pb2+ ions with dibenzopyridino-18-crown-6 in acetonitrile, propionitrile, butyronitrile, benzyl cyanide and benzonitrile has been carried out at various temperatures. Stability constants of the resulting 1:1 complexes were found to decrease with increasing DN, the solvent donor number. The enthalpy and entropy of complexation were calculated from the temperature dependence of the stability constants; the complexes were enthalpy stabilized, but entropy destabilized in all the solvents under study. The relationships DeltaHo vs. DN and DeltaSo vs. DN were found.

2

Conductance Study of the Thermodynamics of Dibenzopyridino-18-crown-6 Complexes with K+, Ti+, Sr2+ and Ba2+ Ions in Acetonitrile Solution

Shamsipur M., Tavakkoli N.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 1

109-116

EN

The complexation reactions between dibenzopyridino-18-crown-6 and Tl+, K+, Sr2+ and Ba2+ ions were studied conductometrically in acetonitrile solution at various temperatures. The formation constants of the resulting 1:1 complexes were calculated from the computer fitting of the molar conductance-mole ratio data at different temperatures. At 25°C, the stability of the resulting complexes varied in the order Ba2+ > Sr2+ > Tl+ > K+. The enthalpy and entropy changes of the complexation reactions were evaluated from the temperature dependence of formation constants. While, the bivalent alkaline earth complexes are both enthalpy and entropy stabilized, the univalent cation complexes used are enthalpy stabilized but entropy destabilized.

3

Competitive Potentiometric study of a Series of 18-Crown-6 with Pb2+, Ag+, and Tl+ Ions in Methanol Using Ag+/Ag Electrode

Zolgarnein J., Azimi G., Habibi M.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 6

795-802

EN

The complexation of Ag+, Tl+ and Pb2+ with 18-crown-6 (18C6), dibenzo-18-crown-6 (DB18C6), dicyclohexyl-18-crown-6 (DCY18C6), and dibenzopyridino-18-crown-6 (DBPY18C6) in methanol solution have been studied by a competitive potentiometry, using Ag+/Ag electrode as a sensor. The stoichiometry and stability constants of resulting complexes have been evaluated by MINIQUAD program. The stoichiometry for all resulting complexes was 1:1. The order of stability of Ag+ complexes with used crown ethers varied as DBPY18C6 > DCY18C6 > 18C6 > DB18C6. For Pb2+, and Tl+ , the sequence of stability of complexes with each of these crown ethers (except of DBPY18C6) varied in the order Pb2+>Ag+>Tl+ . The major trend of stability of resulting complexes of these macrocycle with Pb2+ and Tl+ varied in the order DCY18C6 > 18C6 > DBPY18C6 > DB18C6 with few exceptions.

4

Dibenzopyridino-18-crown-6 as a highly selective and effective carrier for uphill transport of Pb2+ through a bulk liquid membrane

Zolgharnein J., Hosseini S., Sangi M. R., Dadfarnia S., Shamsipur M.

Chemia Analityczna

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2003

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Vol. 48, No. 1

65-75

EN

A chloroform membrane containing a dibenzopyridino-18-crown-6 carrier was found to be an excellent system for the uphill transport of Pb(2+). For P(2+)O4-(7), as a suitable metal cation acceptor in the receiving phase, and picrate, as a counter anion in the source phase, this system can selectively and efficiently transport Pb(2+) from aqueous solutions containing Pb(2+) and interfering cations, such as Ni(2+), Ca(2+), Hg+, Fe(3+), Zn(2+), Cd(2+) and Hg(2+). The amount of Pb(2+) transported across the liquid membrane after 2 h is (96.0š1.2)%.

PL

Chloroformowa membrana zawierająca dibenzopirydyno-18-koronę-6 jako nośnik okazała się doskonałym układem w transporcie jonów ołowiu. Stosując pirofosforan, P(2)O4-(7), jako dogodny akceptor jonów metalu w fazie otrzymującej, a jon pikrynianowy, jako przeciwjon w fazie wyjściowej, uzyskuje się selektywny, działający z dobrą wydajnością efektywny transport jonów ołowiu z roztworów wodnych zawierających takie potencjalnie interferujące jony, jak Ni(2+), Ca(2+), Ag(+), Fe(3+), Zn(2+), Cd2+ and Hg2*. Ilość ołowiu transportowana przez ciekłą membranę wynosi po 2 godz. (96.0š1.2)%.