Dipole–Dipole Coupling Constant for a Directly Bonded CH Pair—A Carbon-13 Relaxation Study

Kowalewski, Józef; Effemey, M.; Jokisaari, Jukka

doi:10.1006/jmre.2002.2590

Cited by 37 publications

(59 citation statements)

References 50 publications

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“…For systems with water molecules in the first coordination sphere of a paramagnetic metal ion, this effect of internal dynamics on the DD coupling will hopefully be small and absorbed in the effective nuclear spin-electron spin distance. 70,71 Given the grossly simplified description of the electron spin dynamics by means of the pseudorotational model, one should in fact not expect an excellent agreement between calculated experimental electron spin and nuclear spin data. The characteristic frequency for the electron spin is three orders of magnitude larger than for the nuclear spin.…”

Section: Discussionmentioning

confidence: 99%

Joint analysis of ESR lineshapes and 1H NMRD profiles of DOTA-Gd derivatives by means of the slow motion theory

Kruk

Kowalewski

Tipikin

et al. 2011

The Journal of Chemical Physics

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The "Swedish slow motion theory" [Nilsson and Kowalewski, J. Magn. Reson. 146, 345 (2000)] applied so far to Nuclear Magnetic Relaxation Dispersion (NMRD) profiles for solutions of transition metal ion complexes has been extended to ESR spectral analysis, including in addition g-tensor anisotropy effects. The extended theory has been applied to interpret in a consistent way (within one set of parameters) NMRD profiles and ESR spectra at 95 and 237 GHz for two Gd(III) complexes denoted as P760 and P792 (hydrophilic derivatives of DOTA-Gd, with molecular masses of 5.6 and 6.5 kDa, respectively). The goal is to verify the applicability of the commonly used pseudorotational model of the transient zero field splitting (ZFS). According to this model the transient ZFS is described by a tensor of a constant amplitude, defined in its own principal axes system, which changes its orientation with respect to the laboratory frame according to the isotropic diffusion equation with a characteristic time constant (correlation time) reflecting the time scale of the distortional motion. This unified interpretation of the ESR and NMRD leads to reasonable agreement with the experimental data, indicating that the pseudorotational model indeed captures the essential features of the electron spin dynamics.

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Section: Discussionmentioning

confidence: 99%

Joint analysis of ESR lineshapes and 1H NMRD profiles of DOTA-Gd derivatives by means of the slow motion theory

Kruk

Kowalewski

Tipikin

et al. 2011

The Journal of Chemical Physics

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“…As explained above, this may possibly be an artefact of the model becoming less accurate at shorter correlation times. One should also keep in mind, however, that the distances obtained from dipolar couplings in solids [16] as well as liquids [17] tend to be systematically longer than the X-ray distances. The uncertainties in the fitted parameters are not easy to assess within the framework of the software that we have used [3].…”

Section: Discussionmentioning

confidence: 97%

“…The exchange lifetime s M =10.7 ns for the [Mn(EDTA) (BOM)] complex at T=298 K, obtained by Aime at al. [1] from 17 O relaxation measurements, is shorter than for the [Mn(EDTA)(BOM)]-HSA system. The fit of the low-field limit was made by holding the five parameters (D T , s V , D, r IS , and h) constant at the values obtained for Table 1.…”

Section: Interpretation Of the [Mn(edta)(bom)] Datamentioning

confidence: 92%

Field-dependent proton relaxation in aqueous solutions of some manganese(II) complexes: a new interpretation

Kruk

Kowalewski

2003

J Biol Inorg Chem

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Field-dependent measurements of the paramagnetic relaxation enhancement for water protons in the presence of Mn(II) complexes ( S=5/2), reported recently, are re-interpreted using theoretical models that take into consideration the fact that the relaxation of the electron spin for S>1 is multiexponential (even in the Redfield limit) and that are valid for an arbitrary relation between the electronic Zeeman interaction and the zero-field splitting in the complex.

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“…The use of the significantly smaller DCC is also justified according to the study of Kowalewski et al, 36 who measured relaxation in the CH 2 group of hexamethylene tetramine (HMTA). Because this molecule is spherical and rigid, its motion can be assumed isotropic, and the DCC and the distance r CH can be determined from the relaxation measurement.…”

Section: Nuclear Spin Relaxation In Solution Mobility Of the 13-alt mentioning

confidence: 99%

“…A better agreement between the different techniques was reached by taking into account vibrational averaging of the DD interaction, which gave an effective NMR bond length of 110.8 pm. 36 The mobility of the propoxy residues on the lower rim of thiacalix [4]arene increases towards the methyl terminus. Compared with the thiacalix [4]arene aromatic moieties, the first methylene group C-1 0 is approximately twice as mobile (the effective correlation time is about one-half), and the methylene C-2 0 is, in turn, twice as mobile as C-1 0 .…”

Section: Nuclear Spin Relaxation In Solution Mobility Of the 13-alt mentioning

confidence: 99%

Reorientational dynamics of two isomers of thiacalix[4]arene

Lang

Tošner

Lhoták

et al. 2003

Magnetic Reson in Chemistry

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Molecular reorientation and local mobility of two isomers of 25,26,27,28-tetrapropoxy-2,8,14,20-tetrathiacalix[4]arene, cone and 1,3-alternate, were studied by means of NMR relaxation. The chemical shift anisotropy of 13 C nuclei was determined in the solid state. Nuclear relaxation due to dipole-dipole interaction and chemical shift anisotropy was analysed in the framework of the Lipari-Szabo approach. The aromatic core of both isomers was found rigid on the subnanosecond time scale. The amplitude of the local motion of the lower rim propoxy substituents increases towards the methyl ends. The methylene groups of the propoxy residues of the cone isomer possess more motional freedom than in the 1,3-alternate, where they are sterically hindered by the adjacent aromatic rings. Global reorientation of the cone is slower than the motion of the 1,3-alternate, which rotates partly anisotropically.

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Dipole–Dipole Coupling Constant for a Directly Bonded CH Pair—A Carbon-13 Relaxation Study

Cited by 37 publications

References 50 publications

Joint analysis of ESR lineshapes and 1H NMRD profiles of DOTA-Gd derivatives by means of the slow motion theory

Joint analysis of ESR lineshapes and 1H NMRD profiles of DOTA-Gd derivatives by means of the slow motion theory

Field-dependent proton relaxation in aqueous solutions of some manganese(II) complexes: a new interpretation

Reorientational dynamics of two isomers of thiacalix[4]arene

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