Phosphorus-31 Solid-State NMR Studies of Homonuclear Spin Pairs in Molybdenum Phosphine Complexes:  Single-Crystal, Dipolar-Chemical Shift, Rotational-Resonance, and 2D Spin−Echo NMR Experiments

1999 ◽  
Vol 38 (4) ◽  
pp. 639-651 ◽  
Author(s):  
Klaus Eichele ◽  
Gabriel C. Ossenkamp ◽  
Roderick E. Wasylishen ◽  
T. Stanley Cameron
Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 908
Author(s):  
Xing-Qi Dong ◽  
Jing-Yu Lin ◽  
Peng-Fei Wang ◽  
Yi Li ◽  
Jian Wang ◽  
...  

The succinate-acetate permease (SatP) is an anion channel with six transmembrane domains. It forms different oligomers, especially hexamers in the detergent as well as in the membrane. Solid-state NMR studies of SatP were carried out successfully on SatP complexes by reconstructing the protein into liposomes or retaining the protein in the native membrane of E. Coli., where it was expressed. The comparison of 13C-13C 2D correlation spectra between the two samples showed great similarity, opening the possibility to further study the acetate transport mechanism of SatP in its native membrane environment. Solid-state NMR studies also revealed small chemical shift differences of SatP in the two different membrane systems, indicating the importance of the lipid environment in determining the membrane protein structures and dynamics. Combining different 2D SSNMR spectra, chemical shift assignments were made on some sites, consistent with the helical structures in the transmembrane domains. In the end, we pointed out the limitation in the sensitivity for membrane proteins with such a size, and also indicated possible ways to overcome it.


2018 ◽  
Vol 20 (48) ◽  
pp. 30174-30188 ◽  
Author(s):  
Andreas Brinkmann ◽  
Ulrich Sternberg ◽  
Petra H. M. Bovee-Geurts ◽  
Isabelle Fernández Fernández ◽  
Johan Lugtenburg ◽  
...  

19F solid-state NMR studies together with bond polarization theory chemical shift tensor calculations provide insight into the chromophore of rhodopsin and its active state Meta II.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1086-C1086
Author(s):  
Ryosuke Kusumi ◽  
Fumiko Kimura ◽  
Tsunehisa Kimura

Solid-state NMR spectroscopy is one of the most widely used methods for investigating crystal structures, along with the X-ray and neutron diffraction methods. Solid-state NMR can provide structural information including isotropic chemical shift, dipolar and quadrupolar couplings, spin diffusion, and chemical shift tensor. Among these, the chemical shift tensor is of particular significance because the electronic environment around a nucleus is directly reflected on the chemical shift tensor. However, full information of the chemical shift tensor, including principal values and axes, is difficult to obtain experimentally because a large single crystal is required for the measurement. On the other hand, we have proposed the use of a magnetically oriented microcrystal array (MOMA) as an alternative to a single crystal.[1,2] A MOMA is a composite in which microcrystals are aligned three-dimensionally, prepared by using a time-dependent magnetic field. We recently demonstrated that the13C chemical shift tensors of L-alanine crystal can be completely determined by application of the standard procedure in the single-crystal rotation method to a MOMA of L-alanine microcrystals,[3] as shown in Figure 1. The L-alanine MOMA produces sharp resonance peaks without resolution enhancement by magic angle spinning (MAS). In addition, we observed that the positions of the13C resonance peaks vary systematically as a function of the angle ψ that is the sample-rotation angle about the axis inclined by the magic angle with respect to the NMR magnetic field. From the ψ-dependence of the chemical shifts,13C chemical shift tensor was completely determined. We confirmed that the combination of MOMA with the single-crystal rotation method can be applied to other nuclei such as31P and15N. These results clearly show that the MOMA method is a powerful tool for obtaining full information of the chemical shift tensor from a microcrystalline powder without MAS.


Polyhedron ◽  
2012 ◽  
Vol 31 (1) ◽  
pp. 241-248 ◽  
Author(s):  
Anna A. Hoser ◽  
Wojciech Schilf ◽  
Anna Szady Chełmieniecka ◽  
Beata Kołodziej ◽  
Bohdan Kamieński ◽  
...  

ChemInform ◽  
2010 ◽  
Vol 25 (25) ◽  
pp. no-no
Author(s):  
R. TACKE ◽  
A. LOPEZ-MRAS ◽  
J. SPERLICH ◽  
C. STROHMANN ◽  
W. F. KUHS ◽  
...  

2017 ◽  
Vol 203 ◽  
pp. 165-186 ◽  
Author(s):  
Scott A. Southern ◽  
Dylan Errulat ◽  
Jamie M. Frost ◽  
Bulat Gabidullin ◽  
David L. Bryce

The feasibility and value of 207Pb solid-state NMR experiments on compounds featuring lead tetrel bonds is explored. Although the definition remains to be formalized, lead tetrel bonds may be qualitatively described as existing when there is evidence of a net attractive interaction between an electrophilic region associated with lead in a molecular entity and a nucleophilic region in another, or the same, molecular entity. Unambiguous identification of lead tetrel bonds can be challenging due to the hypervalent tendency of lead. We report here a series of 207Pb solid-state NMR experiments on five metal–organic frameworks featuring lead coordinated to hydrazone-based ligands. Such frameworks may be held together in part by lead tetrel bonds. The acquisition of 207Pb solid-state NMR spectra for such materials is feasible and is readily accomplished using a combination of magic-angle spinning and Carr–Purcell–Meiboom–Gill methods in moderate to low applied magnetic fields. The lead centres are characterized by 207Pb isotropic chemical shifts ranging from −426 to −2591 ppm and chemical shift tensor spans ranging from 910 to 2681 ppm. Careful inspection of the structures of the compounds and the literature 207Pb NMR data may suggest that a tetrel bond to lead results in chemical shift parameters which are intermediate between those which are characteristic of holodirected and hemidirected lead coordination geometries. Challenges associated with DFT computations of the 207Pb NMR parameters are discussed. In summary, the 207Pb data for the compounds studied herein show a marked response to the presence of non-coordinating electron-rich moieties in close contact with the electrophilic surface of formally hemidirectionally coordinated lead compounds.


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