Quasi-Resonance Fluorine-19 Signal Amplification by Reversible Exchange.

Journal Article (Journal Article)

We report on an extension of the quasi-resonance (QUASR) pulse sequence used for signal amplification by reversible exchange (SABRE), showing that we may target distantly J -coupled 19 F-spins. Polarization transfer from the parahydrogen-derived hydrides to the 19 F nucleus is accomplished via weak five-bond J -couplings using a shaped QUASR radio frequency pulse at a 0.05 T magnetic field. The net result is the direct generation of hyperpolarized 19 F z -magnetization, derived from the parahydrogen singlet order. An accumulation of 19 F polarization on the free ligand is achieved with subsequent repetition of this pulse sequence. The hyperpolarized 19 F signal exhibits clear dependence on the pulse length, irradiation frequency, and delay time in a manner similar to that reported for 15 N QUASR-SABRE. Moreover, the hyperpolarized 19 F signals of 3-19 F-14 N-pyridine and 3-19 F-15 N-pyridine isotopologues are similar, suggesting that (i) polarization transfer via QUASR-SABRE is irrespective of the nitrogen isotopologue and (ii) the presence or absence of the spin-1/2 15 N nucleus has no impact on the efficiency of QUASR-SABRE polarization transfer. Although optimization of polarization transfer efficiency to 19 F (P 19F ≈ 0.1%) was not the goal of this study, we show that high-field SABRE can be efficient and broadly applicable for direct hyperpolarization of 19 F spins.

Full Text

Duke Authors

Cited Authors

  • Ariyasingha, NM; Lindale, JR; Eriksson, SL; Clark, GP; Theis, T; Shchepin, RV; Chukanov, NV; Kovtunov, KV; Koptyug, IV; Warren, WS; Chekmenev, EY

Published Date

  • August 2019

Published In

Volume / Issue

  • 10 / 15

Start / End Page

  • 4229 - 4236

PubMed ID

  • 31291106

Pubmed Central ID

  • PMC6675627

Electronic International Standard Serial Number (EISSN)

  • 1948-7185

International Standard Serial Number (ISSN)

  • 1948-7185

Digital Object Identifier (DOI)

  • 10.1021/acs.jpclett.9b01505

Language

  • eng