Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes.

Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Research Abstract Details 

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Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Abstract Text:

Rachel S Dickins,Silvio Aime,Andrei S Batsanov,Andrew Beeby,Mauro Botta,James I Bruce,Judith A K Howard,Christine S Love,David Parker,Robert D Peacock,Horst Puschmann,

The nature of the ternary complexes formed in aqueous media at ambient pH on reversible binding of acetate, lactate, citrate, and selected amino acids and peptides to chiral diaqua europium, gadolinium, or ytterbium cationic complexes has been examined. Crystal structures of the chelated ytterbium acetate and lactate complexes have been defined in which the carboxylate oxygen occupies an "equatorial" site in the nine-coordinate adduct. The zwitterionic adduct of the citrate anion with [EuL1] was similar to the chelated lactate structure, with a 5-ring chelate involving the apical 3-hydroxy group and the alpha-carboxylate. Analysis of Eu and Yb emission CD spectra and lifetimes (H2O and D2O) for each ternary complex, in conjunction with 1H NMR analyses of Eu/Yb systems and 17O NMR and relaxometric studies of the Gd analogues, suggests that carbonate, oxalate, and malonate each form a chelated (q = 0) square-antiprismatic complex in which the dipolar NMR paramagnetic shift (Yb, Eu) and the emission circular polarization (gem for Eu) are primarily determined by the polarizability of the axial ligand. The ternary complexes with hydrogen phosphate, with fluoride, and with Phe, His, and Ser at pH 6 are suggested to be monoaqua systems with Eu/Gd with an apical bound water molecule. However, for the ternary complexes of simple amino acids with [YbL1]3+, the enhanced charge demand favors a chelate structure with the amine N in an apical position. Crystal structures of the Gly and Ser adducts confirm this. In peptides and proteins (e.g. albumin) containing Glu or Asp residues, the more basic side chain carboxylate may chelate to the Ln ion, displacing both waters.

Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Publishing Authors By Initials

RS Dickins,S Aime,AS Batsanov,A Beeby,M Botta,JI Bruce,JA Howard,CS Love,D Parker,RD Peacock,H Puschmann,

For similar inorganic chemicals: elements: lanthanoid series elements: ytterbium research abstracts see: inorganic chemicals: elements: lanthanoid series elements: ytterbium research

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Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: Journal of the American Chemical Society

VOLUME: 124

Page Numbers: 12697-705

Journal Abbreviation: J. Am. Chem. Soc.

ISSN: 0002-7863

DAY: 30

MONTH: Oct

YEAR: 2002

Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Information

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LANGUAGE: eng

NlmUniqueID: 7503056

Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Keywords Mesh Terms:

KEYWORDS: Ytterbium

MESH TERMS: chemistry

Chemical & Substance for Abstract: Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes. Information

Substance Name: Citric Acid

Registry Number: 77-92-9

Grant and Affiliation Information for Structural, luminescence, and NMR studies of the reversible binding of acetate, lactate, citrate, and selected amino acids to chiral diaqua ytterbium, gadolinium, and europium complexes.

AFFILIATION: Department of Chemistry, University of Durham, South Road, UK. r.s.dickins@dur.ac.uk

Country: United States

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MEDLINETA: J Am Chem Soc

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