Truncated Cross Effect Dynamic Nuclear Polarization: An Overhauser Effect Doppelgänger

Asif Equbal, Yuanxin Li, Alisa Leavesley, Shengdian Huang, Suchada Rajca, Andrzej Rajca, Songi Han

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The discovery of a truncated cross-effect (CE) in dynamic nuclear polarization (DNP) NMR that has the features of an Overhauser-effect DNP (OE-DNP) is reported here. The apparent OE-DNP, where minimal μw power achieved optimum enhancement, was observed when doping Trityl-OX063 with a pyrroline nitroxide radical that possesses electron-withdrawing tetracarboxylate substituents (tetracarboxylate-ester-pyrroline or TCP) in vitrified water/glycerol at 6.9 T and at 3.3 to 85 K, in apparent contradiction to expectations. While the observations are fully consistent with OE-DNP, we discover that a truncated cross-effect (tCE) is the underlying mechanism, owing to TCP's shortened T1e. We take this observation as a guideline and demonstrate that a crossover from CE to tCE can be replicated by simulating the CE of a narrow-line (Trityl-OX063) and a broad-line (TCP) radical pair, with a significantly shortened T1e of the broad-line radical.

Original languageEnglish (US)
Pages (from-to)2175-2180
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume9
Issue number9
DOIs
StatePublished - May 3 2018

Fingerprint

Overhauser effect
Polarization
polarization
Glycerol
Esters
Doping (additives)
Nuclear magnetic resonance
Electrons
Water
glycerols
esters
crossovers
pyrroline
tris(8-carboxyl-2,2,6,6-benzo(1,2-d-4,5-d)-bis(1,3)dithiole-4-yl)methyl sodium salt
nuclear magnetic resonance
augmentation
water
electrons
nitroxyl

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

Cite this

Truncated Cross Effect Dynamic Nuclear Polarization : An Overhauser Effect Doppelgänger. / Equbal, Asif; Li, Yuanxin; Leavesley, Alisa; Huang, Shengdian; Rajca, Suchada; Rajca, Andrzej; Han, Songi.

In: Journal of Physical Chemistry Letters, Vol. 9, No. 9, 03.05.2018, p. 2175-2180.

Research output: Contribution to journalArticle

Equbal, Asif ; Li, Yuanxin ; Leavesley, Alisa ; Huang, Shengdian ; Rajca, Suchada ; Rajca, Andrzej ; Han, Songi. / Truncated Cross Effect Dynamic Nuclear Polarization : An Overhauser Effect Doppelgänger. In: Journal of Physical Chemistry Letters. 2018 ; Vol. 9, No. 9. pp. 2175-2180.
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