NMR of partially aligned liquids: magnetic susceptibility anisotropies and dielectric properties

Zijl, Peter van; Ruessink, B.H.; Bulthuis, J.; MacLean, C.

doi:10.1021/ar00101a004

Cited by 85 publications

(51 citation statements)

References 36 publications

(6 reference statements)

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“…In contrast to conventional ͑nonmesogenic͒ compounds, in which the magnetic anisotropy vanishes above the melting point ͑except some very small anisotropy induced in a strong magnetic field, which can be observed in NMR spectra [25][26][27][28][29][30] ͒, in mesogenic compounds a part of the magnetic anisotropy is retained when going from the crystalline phase to the mesophase due to the alignment of long molecular axes of mol-ecules along the director n. In this section we relate the symmetry and the magnitude of the principal components of the tensor of magnetic susceptibility of the liquid-crystalline phase to those of the tensor of molecular magnetic susceptibility. The latter can be observed in a single crystal, in which metallomesogenic molecules are completely oriented.…”

Section: B Magnetic Anisotropy Of Idealized Monodomain Uniaxial Liqumentioning

confidence: 94%

On the magnetic anisotropy of lanthanide-containing metallomesogens

Mironov

Galyametdinov

Ceulemans

et al. 2000

The Journal of Chemical Physics

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A general theoretical model of the origin of the magnetic anisotropy in paramagnetic metal-containing liquid crystals is developed. General relations between the molecular magnetic anisotropy of mesogenic lanthanide complexes and the macroscopic magnetic anisotropy of these liquid crystals in the mesophase are obtained. The net magnetic anisotropy of a real metallomesogen is shown to be the result of a complex interplay between the molecular magnetic anisotropy, orientation of the long molecular axis, and disorder effects. The sign of the magnetic anisotropy ⌬ depends not only on the anisotropy of the tensor of molecular magnetic susceptibility, but also on the orientation of the long molecular axis of rodlike lanthanide complexes with respect to the principal magnetic axes of the molecular tensor of magnetic susceptibility. The influence of microand macroscopic disorder in real liquid crystals is discussed. Numerical parametric calculations were used to rationalize the variation of the magnitude and sign of the magnetic anisotropy in a series of isostructural lanthanide-containing metallomesogens. Experimental magnetic susceptibility and magnetic anisotropy of a series of ͓Ln͑LH͒ 3 ͑NO 3 ͒ 3 ͔ compounds ͑LH is a Schiff base͒ are well reproduced by calculations based on the present model. Limitations of the Bleaney theory of magnetic anisotropy are analyzed.

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Section: B Magnetic Anisotropy Of Idealized Monodomain Uniaxial Liqumentioning

confidence: 94%

On the magnetic anisotropy of lanthanide-containing metallomesogens

Mironov

Galyametdinov

Ceulemans

et al. 2000

The Journal of Chemical Physics

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“…The theory underlying dipolar and other anisotropic interactions has been described in several places, including in the early liquid crystal applications [15][16][17][18][19][20][21][22][23][24][25] as well as in more recent reviews that deal specifically with biomolecular applications. [26][27][28][29][30][31][32] Here, we provide a brief description of the basic underpinnings of the methodology, with an emphasis on its application to nucleic acids.…”

Section: Residual Dipolar Couplingsmentioning

confidence: 99%

Review NMR studies of RNA dynamics and structural plasticity using NMR residual dipolar couplings

et al. 2007

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An increasing number of RNAs are being discovered that perform their functions by undergoing large changes in conformation in response to a variety of cellular signals, including recognition of proteins and small molecular targets, changes in temperature, and RNA synthesis itself. The measurement of NMR residual dipolar couplings (RDCs) in partially aligned systems is providing new insights into the structural plasticity of RNA through combined characterization of large‐amplitude collective helix motions and local flexibility in noncanonical regions over a wide window of biologically relevant timescales (<milliseconds). Here, we review RDC methodology for studying RNA structural dynamics and survey what has been learnt thus far from application of these methods. Future methodological challenges are also identified. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 384–402, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

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“…If, for example, a uniaxial liquid crystal is orientated by magnetic field (part of the discussion also applies to other agents of orientation, but with material constants other than magnetic susceptibility), the orientating force depends on the anisotropy of the magnetic susceptibility tensor of the material. 45,60,61 If this tensor is such that the phase director aligns parallel to the magnetic field, the sample obtains a uniform orientation. If, on the other hand, the phase director orients at right-angles with respect to the magnetic field, the sample orientation is not uniform: the director can point to any direction in the plane perpendicular to the magnetic field.…”

Section: Oriented Samplesmentioning

confidence: 99%

NMR methods applied to anisotropic diffusion

Furó

Dvinskikh

2002

Magnetic Reson in Chemistry

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The methodology of NMR experiments intended to measure anisotropic diffusion is reviewed. Experiments of this kind preferably require oriented samples and/or orientation-dependent spin coupling and/or magnetic field gradients in different directions. One strategy of diffusion experiments in anisotropic systems with broad NMR lines employs line narrowing techniques, thereby allowing for efficient gradient encoding/decoding. Depending on the nuclei, spin couplings and samples, the preferred methods vary from decoupling through echo techniques to magic angle sample orientation and spinning. Another avenue to efficient gradient encoding/decoding is through very strong magnetic field gradients. Either way, anisotropic diffusion reveals new structural features as illustrated by a few selected examples in liquid crystals and in biological tissues.

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NMR of partially aligned liquids: magnetic susceptibility anisotropies and dielectric properties

Cited by 85 publications

References 36 publications

On the magnetic anisotropy of lanthanide-containing metallomesogens

On the magnetic anisotropy of lanthanide-containing metallomesogens

Review NMR studies of RNA dynamics and structural plasticity using NMR residual dipolar couplings

NMR methods applied to anisotropic diffusion

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