Efficient Dynamic Nuclear Polarization at 800 MHz/527 GHz with Trityl‐Nitroxide Biradicals. (10th September 2015)

• Record Type: Journal Article
• Authors: Mathies, Guinevere; Caporini, Marc A.; Michaelis, Vladimir K.; Liu, Yangping; Hu, Kan‐Nian; Mance, Deni; Zweier, Jay L.; Rosay, Melanie; Baldus, Marc; Griffin, Robert G.
• Is Part Of: Angewandte Chemie. Volume 127:Number 40(2015)
• Page Start: 11936
• Page End: 11940
• Publication Date: 2015-09-10
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201504292
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Cross‐effect (CE) dynamic nuclear polarization (DNP) is a rapidly developing technique that enhances the signal intensities in magic‐angle spinning (MAS) NMR spectra. We report CE DNP experiments at 211, 600, and 800 MHz using a new series of biradical polarizing agents referred to as TEMTriPols, in which a nitroxide (TEMPO) and a trityl radical are chemically tethered. The TEMTriPol molecule with the optimal performance yields a record ¹H NMR signal enhancement of 65 at 800 MHz at a concentration of 10 m<sc>M</sc> in a glycerol/water solvent matrix. The CE DNP enhancement for the TEMTriPol biradicals does not decrease as the magnetic field is increased in the manner usually observed for bis‐nitroxides. Instead, the relatively strong exchange interaction between the trityl and nitroxide moieties determines the magnetic field at which the optimum enhancement is observed.</p> </abstract>