Satellite-Transition MAS NMR of Spin I=3/2, 5/2, 7/2, and 9/2 Nuclei: Sensitivity, Resolution, and Practical Implementation

Ashbrook, Sharon E.; Wimperis, Stephen

doi:10.1006/jmre.2002.2557

Cited by 71 publications

(108 citation statements)

References 32 publications

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“…[12] The subsequent fine adjustment was carried out by maximizing the height of the ST 1 -CT shifted-echo signal in a one-dimensional STMAS experiment. [12,15] Static and MAS deuterium spectra were recorded with a Bruker 4 mm MAS probe. A 500 W RF amplifier was used to give a 2 H 908 pulse duration of 2.9 ms.…”

Section: Methodsmentioning

confidence: 99%

“…The linewidths (full width at half-height, FWHH) of C1 and C7 are only 30 Hz and could be obtained by very accurate adjustment of the magic angle (better than AE 0.0048). [14,15] Such narrow 13 C resonances suggest that the helical framework structure of this coordination polymer experiences very little structural disorder, if any. [16] The linewidths of the other carbon atoms are in the range of 50-80 Hz, and are due in part to residual dipolar splittings (or second-order quadrupoledipole cross-terms) to neighboring 14 N atoms.…”

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confidence: 98%

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A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

et al. 2005

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Bio-inspired supramolecular frameworks are of both fundamental value as models and of practical importance in areas such as materials science, catalysis, and molecular electronics. [1][2][3] Many of these synthetic materials are constructed from metal ions as connectors and ligands as linkers, and are referred to as coordination polymers.[4] Porous materials are of particular interest, as the nanosized cavities lead to novel phenomena, with applications in separation, storage, and catalysis. In this respect, attempts to generate synthetic water channels that mimic aquaporin water channels [5] have met with some success. [6][7][8][9][10] Here we describe a zwitterionic, helical tube of nanodimensions that to some extent mimics aquaporin, and provide a detailed study of the water incorporated inside the channel over a wide temperature range by solidstate 2 H NMR spectroscopy. Reaction of the carboxy-functionalized imidazolium salt N,N'-diacetic acid imidazolium bromide [11] with zinc in aqueous solution affords zwitterionic coordination polymer 1 in crystalline form. The structure of 1 was characterized by single-crystal X-ray diffraction at 140 K and is shown in Figure 1. To ensure that the encapsulated water does not undergo any structural changes at ambient temperature, the structure was also determined at 293 K (see Supporting Information). The macrostructure is formed from ZnBr(H 2 O) units linked by bridging dicarboxylate anions, which assemble into helical channels and appear to be supported by weak pstacking interactions between the imidazolium moieties and by intrahelical hydrogen bonds. The strongest hydrogen bonds stem from contacts of the carboxy oxygen atom O2 to H3 and H6 in the next layer. Two molecules constitute a full cycle within the helix with distances between the layers of 6.234 . The cavity of the channel is occupied by water molecules, which form a one-dimensional chain with distances between the oxygen atoms of 3.157 .The coordination sphere around the zinc anion in 1 is best described as a distorted tetrahedron with angles between 92.5(2) and 117.1(1)8. Zinc-oxygen bond lengths lie between 1.997(2) and 2.014(3) , and both angles and bond lengths are in good agreement with those of comparable zinc dicarboxylate polymers. [12] The helices are packed in a hexagonal-based array with pronounced interhelical hydrogen bonding (Figure 2 b). Each asymmetric unit has five contacts shorter than 3 to neighboring helices, which arise from medium-strength interactions from O1 and O3 and weaker contacts from the bromide ligands. The hydrogen atoms H61 and H62 of the encapsulated water molecule are engaged in strong hydrogen

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Section: Methodsmentioning

confidence: 99%

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confidence: 98%

A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

et al. 2005

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“…Such a narrow resonance is observed for carbonyl carbon atoms of polycrystalline cholesteryl acetate if the magic angle (q m = arccos 3 À1/2 % 54.7368) is adjusted very accurately, that is, within j Dq j = j qÀq m j = 0.0048, as commonly done for satellite-transition magicangle spinning (STMAS) NMR spectroscopy of quadrupolar nuclei. [5,6] The lower limit of the line width (which is inversely proportional to the effective spin-echo decay time constant T 0 2 ) can be as little as 0.09 Hz for carbonyl carbon atoms in choresteryl acetate. We also demonstrate by 207 Pb NMR spectroscopy that temperature gradients across the sample (which lead to a distribution of isotropic chemical shifts) can provide an important contribution to the line width, in addition to imperfect decoupling, [7] structural disorder, [8] and magnetic susceptibility effects.…”

Section: Sasa Antonijevic and Geoffrey Bodenhausen*mentioning

confidence: 99%

High‐Resolution NMR Spectroscopy in Solids by Truly Magic‐Angle Spinning

Antonijevic

Bodenhausen

2005

Angew Chem Int Ed

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Right angles: In solid‐state magic‐angle spinning (MAS) NMR spectra, the line widths of carbonyl carbon atoms in polycrystalline cholesteryl acetate are found to be as narrow as 0.039 ppm if the magic angle is adjusted very accurately, that is, within ±0.004° (see picture). The line broadening observed for slightly miss‐set angles is mostly due to residual chemical shift anisotropy (CSA) interactions. Long spin‐echo life times up to ${{{\rm T}{{\prime \hfill \atop 2\hfill}}}}$=3.6 s open the way to sophisticated NMR methods.

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“…Besides standard methodology, a variety of modern techniques like multi-quantum magic angle spinning NMR have been applied to diverse oxidic scandium compounds [33][34][35][36] in order to get more detailed structural information on these materials, e. g. differentiation of the scandium sites in organically templated scandium fluorophosphate frameworks [37], to work out the influence of the coordination number on the isotropic chemical shift in stabilized zirconia [38] and to systemize the 45 Sc chemical shifts in several basic inorganic scandium compounds [39].…”

Section: Introductionmentioning

confidence: 99%

⁴⁵Sc Solid State NMR Spectroscopy – A Complementary Tool to X‐ray Crystallography for Structure Determination of Intermetallic Compounds

Eckert

Pöttgen

2010

Zeitschrift anorg allge chemie

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45Sc solid state NMR spectroscopy is a useful complementary tool to X‐ray crystallography for structure determination. Recent developments in the field of intermetallic scandium compounds are reviewed. The structural topics concern defect formation, structural disorder, superstructure formation, as well as the detection of multiple scandium sites. To address questions of this kind, high‐resolution 45Sc NMR spectroscopic techniques were established as a new structural tool for the quantification of the local coordination scandium environments and the detailed characterization of their internal NMR interaction parameters. Owing to the moderately sized nuclear electric quadrupole moment of 45Sc, the magic‐angle spinning spectra are affected both by first‐ and second‐order quadrupolar perturbations, which can be analyzed and quantified by fast magic angle spinning, assisted by lineshape simulations. The resolution can be further improved by correlating triple quantum (TQ) with single quantum coherences. Using this 2D NMR spectroscopic methodology, the effects of magnetic shielding and second‐order quadrupolar perturbations on the MAS NMR lineshape can be separated, enabling a more precise experimental characterization of electric field gradients present at the 45Sc nuclei. Structure validation includes the precise measurement of these parameters and comparison with quantum mechanically calculated values based on the atomic positions. In this regard, satisfactory results were obtained using the WIEN2k program.

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Satellite-Transition MAS NMR of Spin I=3/2, 5/2, 7/2, and 9/2 Nuclei: Sensitivity, Resolution, and Practical Implementation

Cited by 71 publications

References 32 publications

A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

High‐Resolution NMR Spectroscopy in Solids by Truly Magic‐Angle Spinning

⁴⁵Sc Solid State NMR Spectroscopy – A Complementary Tool to X‐ray Crystallography for Structure Determination of Intermetallic Compounds

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Satellite-Transition MAS NMR of Spin I=3/2, 5/2, 7/2, and 9/2 Nuclei: Sensitivity, Resolution, and Practical Implementation

Cited by 71 publications

References 32 publications

A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

High‐Resolution NMR Spectroscopy in Solids by Truly Magic‐Angle Spinning

45Sc Solid State NMR Spectroscopy – A Complementary Tool to X‐ray Crystallography for Structure Determination of Intermetallic Compounds

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⁴⁵Sc Solid State NMR Spectroscopy – A Complementary Tool to X‐ray Crystallography for Structure Determination of Intermetallic Compounds