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Titolo:
Determination of the stability constants of mercury(II) complexes of mixeddonor macrobicyclic encapsulating ligands
Autore:
Sharrad, CA; Grondahl, L; Gahan, LR;
Indirizzi:
Univ Queensland, Dept Chem, Sch Mol & Microbial Sci, Brisbane, Qld 4072, Australia Univ Queensland Brisbane Qld Australia 4072 Brisbane, Qld 4072, Australia
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
fascicolo: 19, , anno: 2001,
pagine: 2937 - 2942
SICI:
1472-7773(20011007):19<2937:DOTSCO>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
MACROCYCLIC COMPLEXES; COBALT(II) COMPLEXES; METAL-IONS; SPECTROSCOPY; ENTEROBACTIN; ACID;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
25
Recensione:
Indirizzi per estratti:
Indirizzo: Sharrad, CA Univ Queensland, Dept Chem, Sch Mol & Microbial Sci, Brisbane,Qld 4072, Australia Univ Queensland Brisbane Qld Australia 4072 d 4072, Australia
Citazione:
C.A. Sharrad et al., "Determination of the stability constants of mercury(II) complexes of mixeddonor macrobicyclic encapsulating ligands", J CHEM S DA, (19), 2001, pp. 2937-2942

Abstract

The reactions of mercury(II) with the mixed donor encapsulating ligands 3,6,16-trithia-6,11,19-triazabicyclo[6.6.6]icosane (AMN(3)S(3)sar) and 1-amino-8-methyl-6,19-dithia-3,10,13,16-tetraazabicyclo[6.6.6]icosane (AMN(4)S(2)sar) have been studied. NMR ligand-ligand competition experiments with the ligands 1,4,8,11-tetraazaeyclotetradecane ([14]aneN(4)), 1-thia-4,7,10-triazacyclododecane ([12]aneN(3)S) and ethylenediaminetetraacetic acid (EDTA) with AMN(3)S(3)sar and Hg(II) indicated that [14]aneN(4) would be an appropriate competing ligand for the, determination of the Hg(II) stability constant. Calculations indicated the ratio of concentrations of AMN3S3sar, [14]aneN(4) and Hg(II) required for the determination of the stability constant ranged from 1:1:1 to 1:5:1. Refinement of the titration curves yielded log(10)K[Hg(AMN(3)S(3)sar)](2+) = 17.7. A similar competition titration resultedin the determination of the stability constant for the AMN(4)S(2)sar system as log(10)K[Hg(AMN(4)S(2)sar)](2+) = 19.5. The observed binding constantsfor the mixed N/S donor systems and the hexaaza analogues sar (3,6,10,13,16,19-hexaazabicyclo [6.6.6]icosane) and diamsar (1,8-diamino-3,6,10,13,16,19 -hexazabicyclo [6.6.6] icosane (log(10)K-[Hg(diamsar)](2+) = 26.4; log(10)K[Hg(sar)](2+) = 28.1) differ by approximately ten orders of magnitude. The difference is ascribed not to a cryptate effect but to a mismatch in the Hg-N and Hg-S bond lengths in the N/S systems.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/10/20 alle ore 09:24:55