title: Pulsed Dynamic Nuclear Polarization with Trityl Radicals.
abstract: Continuous-wave (CW) dynamic nuclear polarization (DNP) is now established as a method of choice to enhance the sensitivity in a variety of NMR experiments. Nevertheless, there remains a need for the development of more efficient methods to transfer polarization from electrons to nuclei. Of particular interest are pulsed DNP methods because they enable a rapid and efficient polarization transfer that, in contrast with CW DNP methods, is not attenuated at high magnetic fields. Here we report nuclear spin orientation via electron spin-locking (NOVEL) experiments using the polarizing agent trityl OX063 in glycerol/water at a temperature of 80 K and a magnetic field of 0.34 T. (1)H NMR signal enhancements up to 430 are observed, and the buildup of the local polarization occurs in a few hundred nanoseconds. Thus, NOVEL can efficiently dynamically polarize (1)H atoms in a system that is of general interest to the solid-state DNP NMR community. This is a first, important step toward the general application of pulsed DNP at higher fields.
authors.affiliation: Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Guinevere
authors.initials: G
authors.lastname: Mathies
authors.affiliation: Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Sheetal
authors.initials: S
authors.lastname: Jain
authors.affiliation: Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Marcel
authors.initials: M
authors.lastname: Reese
authors.affiliation: Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Griffin
mesh_terms: D004583:Electrons; D005609:Free Radicals / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D060526:Magnetic Fields; D066244:Proton Magnetic Resonance Spectroscopy; D013696:Temperature; D014320:Triphenylmethyl Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D005609:Free Radicals; D014320:Triphenylmethyl Compounds; D014867:Water; D005990:Glycerol