Enhancing NMR of insensitive nuclei by transfer of SABRE spin hyperpolarization

We describe the performance of methods for enhancing NMR (Nuclear Magnetic Resonance) signals of insensitive, but important NMR nuclei, which are based on the SABRE (Signal Amplification By Reversible Exchange) technique, i.e., on spin order transfer from parahydrogen (H-2 molecule in its nuclear singlet spin state) to a substrate in a transient organometallic complex. Here such transfer is performed at high magnetic fields by INEPT-type NMR pulse sequences, modified for SABRE. Signal enhancements up to three orders of magnitude are obtained for N-15 nuclei; the possibility of sensitive detection of 2D-NMR H-1-N-15 spectra of SABRE complexes and substrates is demonstrated. (C) 2016 Elsevier B.V. All rights reserved.