Quantitation of the chemical shifts induced by tris(dipivalomethanato)europium III in the PMR spectra of hydroxyadamantanes and cyclopentanol

Cockerill, Anthony F.; Rackham, David M.

doi:10.1016/s0040-4039(00)96963-6

Cited by 57 publications

(19 citation statements)

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“…LIS studies of cyclopentanol using Eu reagents to resolve the cyclopentanol protons have been reported. 10,11 Neither of these studies assigned the proton chemical shifts of cyclopentanol itself. Roberts et al 8 used a shift reagent to assign the 13 C-chemical shifts of cis-and trans-3-methyl-and 1,3-dimethylcyclopentanols and hence determined the configuration of these compounds.…”

Section: Perkinmentioning

confidence: 99%

Conformational analysis.

Abraham

Koniotou

Sancassan

2002

J. Chem. Soc., Perkin Trans. 2

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The conformations of cyclopentanol and cis-and trans-cyclopentane-1,2-diol have been studied by ab initio and molecular mechanics (MM) calculations and by the LIS technique, using Yb(fod) 3 to obtain the induced shifts of all 1 H and 13 C nuclei in the molecule, together with complexation shifts obtained by the use of La(fod) 3 . The MM calculations gave two optimised geometries for cyclopentanol. These were envelope conformations with the hydroxyl group equatorial (1A) and axial (1B) at the flap of the envelope. In contrast Gaussian 98 at the B3LYP level with the 6-31G** basis set gave an optimised geometry (1C) which was an envelope conformation with the hydroxyl group in an axial position at the fold of the envelope. ∆E(1A Ϫ 1B) = 0.47 kcal mol Ϫ1 (MM) and 0.93 kcal mol Ϫ1 (ab initio) and ∆E (1B Ϫ 1C) = 0.15 kcal mol Ϫ1 (ab initio). The MM and ab initio calculations for cis-1,2-cyclopentanediol gave different envelope conformations (2A) and ( 2B), both with one equatorial and one axial hydroxyl group. For trans-1,2-cyclopentanediol both calculations gave the same geometries, an envelope conformation with two axial hydroxyls (3A) and a half chair conformer with diequatorial hydroxyls (3B). ∆E (3A Ϫ 3B) = 2.9 kcal mol Ϫ1 ( MM) and 0.70 kcal mol Ϫ1 (ab initio). The LIRAS4 model involving an sp 3 hybridised oxygen atom with two symmetric lone pairs was used for these compounds. The calculated LIS for cyclopentanol gave poor agreement with the observed data for 1A, moderate agreement for 1B but good agreement for 1C. A LIS analysis combining 1B and 1C suggests that the population of 1C was >80% in CHCl 3 solution. The ab initio calculations and the LIS analysis agree that the unsymmetric conformer 1C is the major form in solution. The similarity between this conformer of cyclopentanol and that of the furanose sugars suggests that the anomeric effect may be more fundamental than hitherto realised. In cis-cyclopentane-1,2-diol the observed data were in good agreement with the calculated LIS for both 2A and 2B. In trans-cyclopentane-1,2-diol the observed data were in good agreement with the calculated LIS for 3B but in poor agreement for 3A. The LIS allowed the assignment of the proton chemical shifts of the individual methylene protons in these molecules which had not been given previously.

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Section: Perkinmentioning

confidence: 99%

Conformational analysis.

Abraham

Koniotou

Sancassan

2002

J. Chem. Soc., Perkin Trans. 2

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“…This phenomenon, in particular, the unusual temperature dependence of the middle CF 2 signal (it shows by far the largest line width, which does not change upon increasing the temperature, see Figure S9), deserves some comments. Concerning its origin, apart from the oligomerization and exchanges between dimeric and trimeric forms, assumed in apolar solvents as outlined in Section 1, [ 12,14,16 ] it is tempting to speculate that the different paramagnetic relaxation enhancement (PRE) [ 11,13 ] effects of the Eu 3+ ion can also contribute as long as the adduct life time allows it. [ 2 ]…”

Section: Resultsmentioning

confidence: 99%

“…For that strongly anisotropic spacial distribution of the unpaired electron densities (g‐tensor) is required. [ 11 ]…”

Section: Resultsmentioning

confidence: 99%

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Solution state structure and equilibria of lanthanide (fod)₃ complexes revisited: A ¹H, ¹³C and ¹⁹F nuclear magnetic resonance study of Eu(fod)₃

Szalontai

2021

Magnetic Reson in Chemistry

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In a qualitative approach, variable temperature 1H, 19F and 13C nuclear magnetic resonance (NMR) were used to characterize the solution state structure and equilibria of the widely used lanthanide solvent reagent Eu(fod)3. Despite the fact that the side chain fluorines are far from the coordination site, the 19F–1H NMR spectra turned out to be sensitive reporters of self‐coordination and/or adduct formation with other ligands. For example, they predict/explain immediately the otherwise hardly predictable magnitude of the expectable paramagnetic effects. The temperature‐dependent Fermi‐contact effects observed in the 13C{1H} spectra were extremely important aides in their assignments. The equilibria could be manipulated by changing the solvent used and/or the reagent/ligand molar ratio. Depending on their coordination ability, the solvents possess a certain control over the adduct life times. Sharpening of the 19F signals in the presence of associative solvent molecules such as dimethyl sulfoxide (DMSO) or CH3CN is an indication of changing complex structure (shifting the equilibrium towards the monomeric form). In apolar solvents, relaxation and diffusion data confirmed the oligomerization of the Eu(fod)3–d27 chelate complexes already at relatively low (≥3.0 mg/0.4 ml) concentration.

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“…However, recently also critics and new findings arose concerning the validity of Bleaney's theory about the magnetic properties of lanthanide complexes concerning paramagnetic NMR [52,53]. The very first applications of paramagnetic NMR include the europium shift reagents that allow to increase the shift range in order to resolve signal overlap and determine the enantiomeric ratio of chiral substances by forming a diastereomeric complex in-situ [54][55][56][57][58]. After the successful exploitation of paramagnetic effects of metal ions contained in proteins by Bertini et al, e.g.…”

Section: Paramagnetic Nuclear Magnetic Resonance Spectroscopy On Biommentioning

confidence: 99%

Design and applications of lanthanide chelating tags for pseudocontact shift NMR spectroscopy with biomacromolecules

Joss

Häußinger

2019

Progress in Nuclear Magnetic Resonance Spectroscopy

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In this review, lanthanide chelating tags and their application in pseudocontact shift NMR spectroscopy as well as analysis of residual dipolar couplings are covered. Including a complete overview of non-DOTA-derived and DOTAderived lanthanide chelating tags, critical points in the design of lanthanide chelating tags as appropriate linker moieties, stability under reductive conditions e.g. for in-cell applications, magnitude of the transferred anisotropy from the lanthanide chelating tag to the biomacromolecule under investigation and structural properties as well as conformational bias of the lanthanide chelating tags are discussed. Furthermore, all currently published DOTAderived lanthanide chelating tags used for PCS NMR spectroscopy are displayed in tabular form including their anisotropy parameters with all employed lanthanide ions, CB-Ln distances and tagging reaction conditions, i.e. stoichiometry of lanthanide chelating tag, pH, buffer composition, temperature and reaction time. Additionally, reported applications of lanthanide chelating tags for pseudocontact shifts and residual dipolar couplings on proteins, protein-protein and protein-ligand complexes, carbohydrates, carbohydrate-protein complexes, nucleic acids and nucleic acid-protein complexes are presented and critically reviewed. The vast and impressing field of applications of lanthanide chelating tags in structural investigations of biomacromolecules in solution clearly illustrates the significance of this particular field of research and the extension of the repertoire of lanthanide chelating tags from proteins to nucleic acids holds great promise for the determination of valuable structural parameters and further developments in characterising intermolecular interactions.

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Quantitation of the chemical shifts induced by tris(dipivalomethanato)europium III in the PMR spectra of hydroxyadamantanes and cyclopentanol

Cited by 57 publications

References 1 publication

Conformational analysis.

Conformational analysis.

Solution state structure and equilibria of lanthanide (fod)₃ complexes revisited: A ¹H, ¹³C and ¹⁹F nuclear magnetic resonance study of Eu(fod)₃

Design and applications of lanthanide chelating tags for pseudocontact shift NMR spectroscopy with biomacromolecules

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Quantitation of the chemical shifts induced by tris(dipivalomethanato)europium III in the PMR spectra of hydroxyadamantanes and cyclopentanol

Cited by 57 publications

References 1 publication

Conformational analysis.

Conformational analysis.

Solution state structure and equilibria of lanthanide (fod)3 complexes revisited: A 1H, 13C and 19F nuclear magnetic resonance study of Eu(fod)3

Design and applications of lanthanide chelating tags for pseudocontact shift NMR spectroscopy with biomacromolecules

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Solution state structure and equilibria of lanthanide (fod)₃ complexes revisited: A ¹H, ¹³C and ¹⁹F nuclear magnetic resonance study of Eu(fod)₃