Long-Lived 13C2 Nuclear Spin States Hyperpolarized by Parahydrogen in Reversible Exchange at Microtesla Fields.

Journal Article

Parahydrogen is an inexpensive and readily available source of hyperpolarization used to enhance magnetic resonance signals by up to four orders of magnitude above thermal signals obtained at ∼10 T. A significant challenge for applications is fast signal decay after hyperpolarization. Here we use parahydrogen-based polarization transfer catalysis at microtesla fields (first introduced as SABRE-SHEATH) to hyperpolarize 13C2 spin pairs and find decay time constants of 12 s for magnetization at 0.3 mT, which are extended to 2 min at that same field, when long-lived singlet states are hyperpolarized instead. Enhancements over thermal at 8.5 T are between 30 and 170 fold (0.02 to 0.12% polarization). We control the spin dynamics of polarization transfer by choice of microtesla field, allowing for deliberate hyperpolarization of either magnetization or long-lived singlet states. Density functional theory calculations and experimental evidence identify two energetically close mechanisms for polarization transfer: First, a model that involves direct binding of the 13C2 pair to the polarization transfer catalyst and, second, a model transferring polarization through auxiliary protons in substrates.

Full Text

Duke Authors

Cited Authors

  • Zhou, Z; Yu, J; Colell, JFP; Laasner, R; Logan, A; Barskiy, DA; Shchepin, RV; Chekmenev, EY; Blum, V; Warren, WS; Theis, T

Published Date

  • July 2017

Published In

Volume / Issue

  • 8 / 13

Start / End Page

  • 3008 - 3014

PubMed ID

  • 28594557

Electronic International Standard Serial Number (EISSN)

  • 1948-7185

International Standard Serial Number (ISSN)

  • 1948-7185

Digital Object Identifier (DOI)

  • 10.1021/acs.jpclett.7b00987

Language

  • eng