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The efficiency of DPPH as a polarising agent for DNP-NMR spectroscopy.

ABSTRACT: The free radical 2,2-diphenyl-1-pycrylhydrazyl (DPPH) was tested as a polarising agent for fast dissolution dynamic nuclear polarisation (DNP) NMR spectroscopy. DPPH was found to be reasonably soluble in sulfolane and the optimum concentration for DNP is 20-40 mM depending upon whether short polarisation times or the maximum signal intensity is needed. W-band ESR measurements revealed that the ESR linewidth D of DPPH is intermediate between that of BDPA and 4-oxo-TEMPO. Several thousand-fold NMR signal enhancements in the liquid-state were achieved for (13)C, (15)N, (89)Y, and (109)Ag compounds, demonstrating that DPPH can be added to the list of polarising agents for DNP-NMR spectroscopy. Furthermore, the hydrophobic DPPH free radical can be easily filtered out from the dissolution liquid when water is used as the dissolution solvent.

SUBMITTER: Lumata L

PROVIDER: S-EPMC3507463 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

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The efficiency of DPPH as a polarising agent for DNP-NMR spectroscopy.

Lumata Lloyd L Merritt Matthew M Khemtong Chalermchai C Ratnakar S James SJ van Tol Johan J Yu Lu L Song Likai L Kovacs Zoltan Z

RSC advances 20120101 33

The free radical 2,2-diphenyl-1-pycrylhydrazyl (DPPH) was tested as a polarising agent for fast dissolution dynamic nuclear polarisation (DNP) NMR spectroscopy. DPPH was found to be reasonably soluble in sulfolane and the optimum concentration for DNP is 20-40 mM depending upon whether short polarisation times or the maximum signal intensity is needed. W-band ESR measurements revealed that the ESR linewidth D of DPPH is intermediate between that of BDPA and 4-oxo-TEMPO. Several thousand-fold NMR ...[more]

PMID: 23205273

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