Nuclear magnetic resonance spectroscopy of lanthanide complexes with a tetraacetic tetraaza macrocycle. Unusual conformation properties

Desreux, Jean F.

doi:10.1021/ic50207a042

Cited by 341 publications

(323 citation statements)

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“…The study of the significant shifts induced by the paramagnetic lanthanide ions on the nuclear magnetic resonances of the ligand (lanthanide-induced shifts, LIS) can help to determine the structure of the corresponding chelates [7]. Desreux and co-workers first studied the Ln(DOTA)-complexes in aqueous solution, using both 1H and 13C dynamic NMR spectroscopy [8], having detected a very slow kinetics of formation for these species, at room temperature, that has been partially explained by their unusual stereodynamic behaviour. The solution structure and dynamics of these chelates have lately been the subject of thorough investigation by different workers [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

NMR conformational study of the lanthanide(III) complexes of DOTA in aqueous solution

Marques

Geraldes

Sherry

et al. 1995

Journal of Alloys and Compounds

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Variable temperature NMR spectroscopy studies of lanthanide(III) complexes with 1,4,7,10-tetraazacyclododecane-N,N',N",N'-tetraacetic acid (DOTA) provide evidence of the presence of two isomeric forms in aqueous solution. An NMR study was performed in order to gain structural information on the two isomeric species, using a fitting procedure of calculated to experimental dipolar contributions to the paramagnetic shifts. The two isomers show to have identical macrocyclic ring conformations and differ only in the coordination or orientation of the acetate arms of the ligand, yielding either square prismatic and square anti-prismatic coordination geometries, or octadentate and heptadentate coordinations of the ligand relative to the lanthanide ion. Analysis of the dipolar shifts is consistent with both types of acetate conformational equilibria.

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Section: Introductionmentioning

confidence: 99%

NMR conformational study of the lanthanide(III) complexes of DOTA in aqueous solution

Marques

Geraldes

Sherry

et al. 1995

Journal of Alloys and Compounds

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“…A typical separation procedure was carried out at room temperature with a gradient of water-acetonitrile containing 0.1% trifluoroacetic acid (TFA) from 95:5 to 10:90 in 35 min detection at 215 and 250 nm unless stated otherwise. DOTA was prepared according to a previously reported methodology (17). Protected L-amino acids were purchased from Bachem Americas Inc. (Torrance, CA, USA), Novabiochem (San Diego, CA, USA) or Aroz Tech, LLC.…”

Section: Resultsmentioning

confidence: 99%

Untitled

2010

Contrast Media & Molecular

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The synthesis of new DOTA tetraamide (DOTAMR 4 ) compounds is of great interest given their application in the formation of Ln(III) complexes as potential PARACEST contrast agents in MRI or fluorescent molecular probes. In this context amino acid and peptide DOTAMR 4 derivatives are particularly attractive since the amino-acid and/or peptide moiety can show responsive properties dependent on a given stimuli which might translate to changes in water exchange rates of the corresponding Ln(III) complex. Current synthesis of DOTAMR 4 derivatives is typically carried out by reacting haloacetamide intermediates with cyclen. However, this method fails to generate the tetra-substituted products when bulky substituents are present in the haloacetamide and in some cases this intermediate cannot be prepared by conventional acylation procedures limiting the number of DOTAMR 4 compounds available for study. As a solution to these limitations, an improved methodology for the synthesis of DOTAMR 4 by coupling DOTA to an appropriate amine containing reagent (i.e. protected amino-acids with the a-amino group free) is presented in this work. Several DOTAMR 4 derivatives which are difficult or impossible to prepare with the traditional methodologies were easily obtained starting with DOTA. A new protocol was derived using this methodology for the solution-phase synthesis of DOTA peptide derivatives. With this methodology, many other DOTAMR 4 peptide and non-peptide derivatives have been prepared in our laboratories with several of these new compounds showing interesting properties for molecular imaging.

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“…Most complexones are commercially available at high purity, with the exception of DOTA, TETA, and NOTA [82WB,80DE,77TT]. These macrocyclic compounds are prepared by several synthetic steps, and the purification of the final compound is difficult.…”

Section: General Physicochemical Properties Of Complexonesmentioning

confidence: 99%

Critical Evaluation of Stability Constants of Metal Complexes of Complexones for Biomedical and Environmental Applications (IUPAC Technical Report)

2005

Chemistry International -- Newsmagazine for IUPAC

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Nuclear magnetic resonance spectroscopy of lanthanide complexes with a tetraacetic tetraaza macrocycle. Unusual conformation properties

Cited by 341 publications

References 2 publications

NMR conformational study of the lanthanide(III) complexes of DOTA in aqueous solution

NMR conformational study of the lanthanide(III) complexes of DOTA in aqueous solution

Untitled

Critical Evaluation of Stability Constants of Metal Complexes of Complexones for Biomedical and Environmental Applications (IUPAC Technical Report)

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