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Communication Dans Un Congrès Année : 2016

Dynamic Nuclear Polarization at 40 kHz Magic Angle Spinning

Résumé

Solid-state NMR spectroscopy has become one of the most important anaytical techniques for structure elucidation and dynamic studies for biological samples as well as for a wide range of materials. However, its applications are often hampered by its intrinsically low sensitivity. Dynamic Nuclear Polarization (DNP) is currently emerging as a powerful new approach,which can overcome this sensitivity issue by transferring the large polarization of unpaired electrons to neighboring nuclei. Continuous wave Magic Angle Spinning (MAS) DNP can proceed via several mechanisms including Solid-Effect (SE), Cross-Effect(CE), and Overhauser Effect (OE). Many aspects of these mechanisms have received much attention in order to improve the performance of DNP. Thusthe design of optimized binitroxide polarizationsources made it possible to enhance the NMR signals by more than 2 orders of magnitude at 9.4 Tand 100 K. Although sample spinning is an intrinsic part of these experiments, the sample spinning rate itself has so far received little attention. For biradicals featuring the CE, simulations predict a decrease of the enhancements with increasing MAS rate (2-5). Using a prototype 1.3 mm MAS probe operating at 18.8 T and 100 K we have recently shown that signal amplification factors could be increased by up to a factor two when using smaller volume rotors as comparedto 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz (6). We will present new investigations on the MAS frequency dependence of other DNP mechanisms. The overall sensitivity enhancement factor in this spinning regime will be discussed and new applications will be presented.
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Dates et versions

hal-01576235 , version 1 (22-08-2017)

Identifiants

  • HAL Id : hal-01576235 , version 1

Citer

Sachin R Chaudhari, Pierrick Berruyer, Dorothea Wisser, David Gajan, Christian Reiter, et al.. Dynamic Nuclear Polarization at 40 kHz Magic Angle Spinning. Journées Grand-Sud de RMN, May 2016, Montpellier, France. ⟨hal-01576235⟩
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