Heterogeneous Parahydrogen Pairwise Addition to Cyclopropane

Oleg G. Salnikov, Kirill V. Kovtunov, Panayiotis Nikolaou, Larisa M. Kovtunova, Valerii I. Bukhtiyarov, Igor V. Koptyug, Eduard Y. Chekmenev

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Hyperpolarized gases revolutionize functional pulmonary imaging. Hyperpolarized propane is a promising emerging contrast agent for pulmonary MRI. Unlike hyperpolarized noble gases, proton-hyperpolarized propane gas can be imaged using conventional MRI scanners with proton imaging capability. Moreover, it is non-toxic odorless anesthetic. Furthermore, propane hyperpolarization can be accomplished by pairwise addition of parahydrogen to propylene. Here, we demonstrate the feasibility of propane hyperpolarization via hydrogenation of cyclopropane with parahydrogen. 1H propane polarization up to 2.4 % is demonstrated here using 82 % parahydrogen enrichment and heterogeneous Rh/TiO2 hydrogenation catalyst. This level of polarization is several times greater than that obtained with propylene as a precursor under the same conditions despite the fact that direct pairwise addition of parahydrogen to cyclopropane may also lead to formation of propane with NMR-invisible hyperpolarization due to magnetic equivalence of nascent parahydrogen protons in two CH3 groups. NMR-visible hyperpolarized propane demonstrated here can be formed only via a reaction pathway involving cleavage of at least one C–H bond in the reactant molecule. The resulting NMR signal enhancement of hyperpolarized propane was sufficient for 2D gradient echo MRI of ∼5.5 mL phantom with 1×1 mm2 spatial resolution and 64×64 imaging matrix despite relatively low chemical conversion of cyclopropane substrate.

Original languageEnglish
Pages (from-to)2621-2626
Number of pages6
JournalChemPhysChem
Volume19
Issue number20
DOIs
Publication statusPublished - 19 Oct 2018

Keywords

  • contrast agent
  • cyclopropane
  • hydrogenation
  • hyperpolarization
  • parahydrogen-induced polarization
  • Protons
  • Magnetic Resonance Spectroscopy
  • Magnetic Resonance Imaging/methods
  • Hydrogen/chemistry
  • Hydrogenation
  • Feasibility Studies
  • Catalysis
  • Cyclopropanes/chemistry
  • LUNG
  • MRI
  • SOURCE XE-129 HYPERPOLARIZER
  • HYDROGEN-INDUCED POLARIZATION
  • PROPANE GAS
  • OBSTRUCTIVE PULMONARY-DISEASE
  • NMR SIGNAL ENHANCEMENT
  • MAGNETIC-RESONANCE
  • LIVED SPIN STATES
  • NUCLEAR-POLARIZATION

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