Document Detail


Norbadione a: kinetics and thermodynamics of cesium uptake in aqueous and alcoholic media.
MedLine Citation:
PMID:  20831226     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Norbadione A (NbA) is a mushroom pigment, which is assumed to be involved in (137)Cs accumulation all over Europe during the Chernobyl nuclear accident. NbA bears seven acid-base functional groups, among which are two enolic and two carboxylic acid moieties. This work deals with complex formation of Cs(+) and NbA in ethanol, ethanol/water (9:1) (M1), and water with, when required, the support of two Cs(+) ionophore probes, calix[4]arene-bis(crown-6-ether)dioxycoumarine (A1) and its tetrasuslfonated form (A2). In ethanol, two Cs(+) complexes are formed, with the affinity constants K(1EtOH) = (1.1 ± 0.25) × 10(5) and K(2EtOH) = (2.1 ± 0.4) × 10(3). In M1, a single Cs(+) complex occurs when only the enols are deprotonated, whereas a bicomplex is formed when both enols and carboxylic acids are deprotonated: K(1M1) = (1.5 ± 0.3) × 10(5) and K(2M1) = (4 ± 2) × 10(3). These data are confirmed by stopped-flow and T-jump kinetics. In ethanol, a fast Cs(+) exchange occurs between NbA and A1: direct rate constant, k(1) = (3.1 ± 0.1) × 10(7) M(-1) s(-1); reverse rate constant k(-1) = (2.8 ± 1) × 10(5) M(-1) s(-1); and Cs(+) exchange constant, K(1Exchange) = (9 ± 4) × 10(-3). In M1, the quenching of A2 fluorescence by NbA is used to determine the kinetics of complex formation with Cs(+): k(2) = (1.8 ± 0.4) × 10(9) M(-1) s(-1); k(-2) = (1.80 ± 0.15) × 10(4) s(-1); and K(1M1) = (1.5 ± 0.5) × 10(5). The affinity of NbA for Cs(+) is probably the result of the particular structure in which the two pulvinic acid arms adopt a conformation that forms two complexation sites composed of the two enolates and/or the two carboxylates. This renders the efficiency in Cs(+) uptake comparable to that of some calixarenes or crown ethers.
Authors:
Alexandre Korovitch; Jean-Baptiste Mulon; Vincent Souchon; Isabelle Leray; Bernard Valeur; Aurélie Mallinger; Brice Nadal; Thierry Le Gall; Claude Lion; Nguyêt-Thanh Ha-Duong; Jean-Michel El Hage Chahine
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The journal of physical chemistry. B     Volume:  114     ISSN:  1520-5207     ISO Abbreviation:  J Phys Chem B     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-30     Completed Date:  2011-01-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101157530     Medline TA:  J Phys Chem B     Country:  United States    
Other Details:
Languages:  eng     Pagination:  12655-65     Citation Subset:  IM    
Affiliation:
Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université Paris 7-CNRS UMR 7086, Bât. Lavoisier, 15 rue Jean Antoine de Baïf, 75205 Paris Cedex 13, France.
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MeSH Terms
Descriptor/Qualifier:
4-Butyrolactone / analogs & derivatives*,  chemistry
Agaricales / chemistry
Cesium / chemistry*,  metabolism
Cesium Radioisotopes / chemistry,  metabolism
Coordination Complexes / chemistry
Ethanol / chemistry*
Hydrogen-Ion Concentration
Kinetics
Phenylacetates / chemistry*
Thermodynamics
Water / chemistry*
Chemical
Reg. No./Substance:
0/Cesium Radioisotopes; 0/Coordination Complexes; 0/Phenylacetates; 64-17-5/Ethanol; 7440-46-2/Cesium; 7732-18-5/Water; 90295-68-4/norbadione A; 96-48-0/4-Butyrolactone

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