Indirectly detected through-bond chemical shift correlation NMR spectroscopy in solids under fast MAS: Studies of organic–inorganic hybrid materials

Mao, Kanmi; Wiench, Jerzy W.; Lin, Victor S.‐Y.; Pruski, Marek

doi:10.1016/j.jmr.2008.10.010

Cited by 88 publications

(103 citation statements)

References 23 publications

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“…Owing to these favorable properties several studies of immobilized species on surfaces employing modern techniques of solidstate NMR are reported in the literature. [23,[52][53][54] In this work we use a combination of 29 Si and advanced 31 P solid-state NMR methods to investigate and characterize modified surface of mesoporous silica and to study the exact binding of Wilkinsons complex to the modified silica surface. We demonstrate that the 31 P J-resolved 2D slow-spinning magic-angle-spinning (MAS) and Off-MAS 31 P NMR techniques are efficient tools to reveal the detailed binding situation of the supported [RhClA C H T U N G T R E N N U N G (PPh 3 ) 3 ] molecule.…”

Section: Introductionmentioning

confidence: 99%

Solid‐State NMR Characterization of Wilkinson’s Catalyst Immobilized in Mesoporous SBA‐3 Silica

Grünberg

Breitzke

et al. 2010

Chemistry A European J

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The Wilkinson's catalyst [RhCl(PPh(3))(3)] has been immobilized inside the pores of amine functionalized mesoporous silica material SBA-3 and The structure of the modified silica surface and the immobilized rhodium complex was determined by a combination of different solid-state NMR methods. The successful modification of the silica surface was confirmed by (29)Si CP-MAS NMR experiments. The presence of the T(n) peaks confirms the successful functionalization of the support and shows the way of binding the organic groups to the surface of the mesopores. (31)P-(31)P J-resolved 2D MAS NMR experiments were conducted in order to characterize the binding of the immobilized catalyst to the amine groups of the linkers attached to the silica surface. The pure catalyst exhibits a considerable (31)P-(31)P J-coupling, well resolvable in 2D MAS NMR experiments. This J-coupling was utilized to determine the binding mode of the catalyst to the linkers on the silica surface and the number of triphenylphosphine ligands that are replaced by coordination bonds to the amine groups. From the absence of any resolvable (31)P-(31)P J-coupling in off-magic-angle-spinning experiments, as well as slow-spinning MAS experiments, it is concluded, that two triphenylphosphine ligands are replaced and that the catalyst is bonded to the silica surface through two linker molecules.

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Section: Introductionmentioning

confidence: 99%

Solid‐State NMR Characterization of Wilkinson’s Catalyst Immobilized in Mesoporous SBA‐3 Silica

Grünberg

Breitzke

et al. 2010

Chemistry A European J

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“…ramamoor@umich.edu pharmaceutics, 15 inorganic materials, 16,17 and membrane proteins. [18][19][20][21][22] For high-throughput utilization of solid-state NMR spectroscopy, 1 H NMR experiments are always desired due to the high natural-abundance and large gyromagnetic ratio of protons that render high sensitivity of detection.…”

Section: 5mentioning

confidence: 99%

“…[23][24][25][26] These developments are significantly impacting the applications of various proton-detected solid-state NMR experiments, which also provide additional significant enhancement in signal-to-noise ratio. 16,[26][27][28][29][30][31][32][33][34][35][36] In fact, under ultrafast MAS, the introduction of 1 H-1 H dipolar recoupling sequence becomes necessary for controlling and utilizing the dipolar-couplingbased spin diffusion process to accomplish through-space correlation of chemical shifts. [37][38][39][40][41] In this study, we propose a dipolar filter (or the dipolar-coupling filter) based pulse sequence to selectively detect correlation of 1 H isotropic chemical shifts from mobile regions of a system under ultrafast MAS conditions.…”

Section: 5mentioning

confidence: 99%

Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

Zhang

Ramamoorthy

2015

The Journal of Chemical Physics

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Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90• RF pulses) to selectively measure the correlation of 1 H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90• pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1 H/ 1 H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials. C 2015 AIP Publishing LLC. [http://dx

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“…7,8 Therefore, a combination of through-bond and through-space correlation experiments could be used to determine molecular structures and inter-molecular assemblies. Inspite of the development of a diverse set of dipolar-coupling driven experiments and their application to determine heteronuclear/homonuclear connectivity and distances, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] relatively few experiments [24][25][26][27][28][29][30][31][32] make use of scalar coupling for structural studies due to its smaller magnitude, when compared to dipolar coupling, in solids. For example, the dipolar coupling between single bonded 13 C− 13 C pair is around 2 kHz, whereas the scalar coupling is only around 55 Hz.…”

Section: Introductionmentioning

confidence: 99%

Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

Zhang

Ramamoorthy

2016

The Journal of Chemical Physics

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Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D 1 H/ 13 C/ 1 H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t 1 and t 3 periods, respectively. In addition to through-space and through-bond 13 C/ 1 H and 13 C/ 13 C chemical shift correlations, the 3D 1 H/ 13 C/ 1 H experiment also provides a COSY-type 1 H/ 1 H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices ( 1 H/ 1 H chemical shift correlation spectrum) at different 13 C chemical shift frequencies from the 3D 1 H/ 13 C/ 1 H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the 3D 1 H/ 13 C/ 1 H experiment would be useful to study the structure and dynamics of a variety of chemical and biological solids. C 2016 AIP Publishing LLC. [http://dx

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Indirectly detected through-bond chemical shift correlation NMR spectroscopy in solids under fast MAS: Studies of organic–inorganic hybrid materials

Cited by 88 publications

References 23 publications

Solid‐State NMR Characterization of Wilkinson’s Catalyst Immobilized in Mesoporous SBA‐3 Silica

Solid‐State NMR Characterization of Wilkinson’s Catalyst Immobilized in Mesoporous SBA‐3 Silica

Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

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