title: NMR SLIC Sensing of Hydrogenation Reactions Using Parahydrogen in Low Magnetic Fields.
abstract: Parahydrogen-induced polarization (PHIP) is an NMR hyperpolarization technique that increases nuclear spin polarization by orders of magnitude, and it is particularly well-suited to study hydrogenation reactions. However, the use of high-field NMR spectroscopy is not always possible, especially in the context of potential industrial-scale reactor applications. On the other hand, the direct low-field NMR detection of reaction products with enhanced nuclear spin polarization is challenging due to near complete signal cancellation from nascent parahydrogen protons. We show that hydrogenation products prepared by PHIP can be irradiated with weak (on the order of spin-spin couplings of a few hertz) alternating magnetic field (called Spin-Lock Induced Crossing or SLIC) and consequently efficiently detected at low magnetic field (e.g., 0.05 T used here) using examples of several types of organic molecules containing a vinyl moiety. The detected hyperpolarized signals from several reaction products at tens of millimolar concentrations were enhanced by 10000-fold, producing NMR signals an order of magnitude greater than the background signal from protonated solvents.
authors.affiliation: Vanderbilt University Institute of Imaging Sciences , Nashville, Tennessee 37232, United States.
authors.forename: Danila A
authors.initials: DA
authors.lastname: Barskiy
authors.affiliation: International Tomography Center SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
authors.forename: Oleg G
authors.initials: OG
authors.lastname: Salnikov
authors.affiliation: Vanderbilt University Institute of Imaging Sciences , Nashville, Tennessee 37232, United States.
authors.forename: Roman V
authors.initials: RV
authors.lastname: Shchepin
authors.affiliation: Vanderbilt University Institute of Imaging Sciences , Nashville, Tennessee 37232, United States.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Feldman
authors.affiliation: Vanderbilt University Institute of Imaging Sciences , Nashville, Tennessee 37232, United States.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Coffey
authors.affiliation: International Tomography Center SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
authors.forename: Kirill V
authors.initials: KV
authors.lastname: Kovtunov
authors.affiliation: International Tomography Center SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
authors.forename: Igor V
authors.initials: IV
authors.lastname: Koptyug
authors.affiliation: Vanderbilt University Institute of Imaging Sciences, Nashville, Tennessee 37232, United States; Russian Academy of Sciences, Moscow 119991, Russia.
authors.forename: Eduard Y
authors.initials: EY
authors.lastname: Chekmenev