Dynamic Nuclear Polarization Opens New Perspectives for NMR Spectroscopy in Analytical Chemistry

Abstract

Dynamic nuclear polarization (DNP) can boost sensitivity in nuclear magnetic resonance (NMR) experiments by several orders of magnitude. This Feature illustrates how the coupling of DNP with both liquid- and solid-state NMR spectroscopy has the potential to considerably extend the range of applications of NMR in analytical chemistry.

A Strategy for Probing the Evolution of Crystallization Processes by Low-Temperature Solid-State NMR and Dynamic Nuclear Polarization

“…If new transient solid forms are observed within the frozen solution, such NMR techniques have the potential to reveal detailed insights into their structural properties. Furthermore, the low temperatures involved allow dynamic nuclear polarization (DNP) [19][20][21][22][23][24][25][26][27][28][29][30][31][32] to be exploited to enhance the signal intensity in solid-state NMR studies of the frozen crystallization system. The method is demonstrated here in studies of crystallization of glycine [H2C(NH3 + )(CO2…”

Surface enhanced dynamic nuclear polarization solid-state NMR spectroscopy sheds light on Brønsted–Lewis acid synergy during the zeolite catalyzed methanol-to-hydrocarbon process

“…To overcome the low-sensitivity concerns, dynamic nuclear polarization surface-enhanced NMR spectroscopy (DNP SENS) has recently gained a lot of interest from the scientic community. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] Typically, a sample is initially impregnated with a DNP agent (i.e., a nitroxide biradical) containing solution to bring it into the vicinity of the surface. 29,30,[37][38][39][40][41][42][43]45,46 The DNP agent enhances the polarization of protons of the solvent and neighbouring surface regions, which are then transferred to the surface's hetero-nuclei through cross-polarization (CP) or similar coherence magnetization transfer schemes (as illustrated in Fig.…”

“…As a result, signal enhancement of the hetero-nuclei is observed without any isotope-enrichment. 29,30,37,40,45,46 In heterogeneous catalysis and materials science, until now, the concept of DNP SENS has been primarily utilized to characterize surface organometallic fragments/catalysts, metalorganic frameworks (MOFs), and amorphous aluminosilicates. 40,[45][46][47][48] To understand the reaction mechanism involving micro-porous zeolite catalysts, fully 13 C-enriched reactants have typically been used to deal with the natural abundance issue of the hetero-nuclei, including in MTH catalysis.…”

Solvent suppression in solid‐state DNP NMR using Electronic Mixing‐Mediated Annihilation (EMMA)

“…High-field dynamic nuclear polarization (DNP) solidstate nuclear magnetic resonance (NMR) can dramatically increase the strength of the NMR signal. [1][2][3][4][5][6][7][8][9][10][11] DNP experiments usually rely on the polarization transfer from the electronic spin polarization to the nuclear spin. Consequently, in the case of diamagnetic insulating solids, an exogenous paramagnetic polarizing agent should be added to the sample under study.…”