Paramagnetic shifts in solutions of cholesterol and the dipyridine adduct of trisdipivalomethanatoeuropium(III). A shift reagent

Hinckley, C.C.

doi:10.1021/ja01046a038

Cited by 579 publications

(120 citation statements)

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“…We tend to favor the latter possibility as does Bentrude for the corresponding trans-5-t-butyl phosphite. Using In recent months many reports of the application of lanthanide complexes to spread out and simplify proton spectra have appeared in the literature (26,27). The origin of the induced effects is thought to involve a pseudocontact interaction (28).…”

Section: Proton Chemical Shiftsmentioning

confidence: 99%

Conformational Studies of Substituted Trimethylene Sulfites by Proton Magnetic Resonance

Wood¹,

Buchanan²,

Miskow³

1972

Can. J. Chem.

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Proton n.m.r. chemical shifts and coupling constants are reported for trimethylene sulfite and 10 alkyl derivatives in CC14. Data are discussed in terms of possible chair and non-chair conformations and results arecompared with those from dipole moment studies. The shift reagent Eu(dpm), is used to aid configurational assignments. Conclusions from n.m.r. and dipole moments are consistent and indicate that several of the sulfites exist to a considerable degree in non-chair conformations.Les dbplacements chimiques des protons en r.m.n. et les constantes de couplage sont donntes dans CC14 pour le trimethylene sulfite et pour dix derives alkylts. Les donntes sont discutees en fonction des conformations possibles chaise et non-chaise et les resultats compares a ceux des ttudes de moment dipolaire. Le reactif de deplacement Eu(dpm), est utilisb pour faciliter les assignations de configuration. Les conclusions tirees de la r.m.n. et des moments dipolaires sont importantes et indiquent que plusieurs des sulfites existent pour une part importante sous des conformations non-chaise.

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Section: Proton Chemical Shiftsmentioning

confidence: 99%

Conformational Studies of Substituted Trimethylene Sulfites by Proton Magnetic Resonance

Wood¹,

Buchanan²,

Miskow³

1972

Can. J. Chem.

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“…In most cases, these lanthanide-induced shifts (LIS) are very sensitive to structural changes associated with changes in pH, temperature and counter-ions, allowing the lanthanide complexes to be used for many purposes, such as elucidation of molecular conformation [2,3], resolution of enantiomers [4], detection of coordinated water numbers of lanthanide complexes [5], simplification of NMR spectra [6], separation of transmembrane cation resonances [7,8] and temperature probes in biological systems [9 Á/11].…”

Section: Introductionmentioning

confidence: 99%

Analysis of lanthanide induced NMR shifts using a crystal field independent method: application to complexes of tetraazamacrocyclic ligands

Ren

Zhang

Sherry

et al. 2002

Inorganica Chimica Acta

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The linear graphical analysis of the LIS NMR data available for the axially symmetric complexes [Ln(DOTA)] ( (M and m isomers), [Ln(DOTP)] 5( (pH 10.0, 7.0 and 3) and [Ln(DOTEA)] 3' using the classical crystal field dependent method and a crystal field independent method were compared. As the second method provides ratios of geometric structural terms G rather than G values, the effect of lanthanide contraction was reduced. Thus, the large breaks in plots observed for all nuclei of those systems using the classical method are still present in the plots of the second method, only in a few of the nuclei and much reduced. This shows that the large breaks at the middle of the lanthanide series present in plots of the classical method as well as the anomalies often present for those plots for the Tm and Yb ions are mostly due to changes of the crystal field coefficient A 2 0 r 2 along the lanthanide series, while both the hyperfine coupling constants and the ratios of geometric terms also change as a result of the lanthanide contraction, leading to small breaks at the middle of the lanthanide series. Analysis of the proton shifts of [Ln(DOTP)] complexes at pH 10, 7 and 3 indicates that protonation of the complexes results in a decrease on the crystal field coefficient. The dipolar shift ratios and absolute shifts obtained were also interpreted in terms of the structural models for those complexes in solution and their available Xray crystal structures. #

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“…4 These reagents are effective in differentiating between NMR signals of similar chemical shift and have become a dependable tool in identifying the structure of a variety of molecules. 5 The paramagnetic effects of the shift reagent result in significant increases in chemical shifts based on the distance between the nuclei being observed and the lanthanide.…”

mentioning

confidence: 99%

Structural Elucidation of a Photocycloaddition Dimer of Cyclohexenone

et al. 1999

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Paramagnetic shifts in solutions of cholesterol and the dipyridine adduct of trisdipivalomethanatoeuropium(III). A shift reagent

Cited by 579 publications

References 0 publications

Conformational Studies of Substituted Trimethylene Sulfites by Proton Magnetic Resonance

Conformational Studies of Substituted Trimethylene Sulfites by Proton Magnetic Resonance

Analysis of lanthanide induced NMR shifts using a crystal field independent method: application to complexes of tetraazamacrocyclic ligands

Structural Elucidation of a Photocycloaddition Dimer of Cyclohexenone

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