Fig. 7
Heteronuclear SABRE hyperpolarization. a 15N NMR spectra of pyridine-15N (25 mM) achieved with indicated [IrCl(COD)(NHC)] (2.5 mM) precatalyst using the conditions: (i) thermal polarization recorded with 1024 scans (×64 vertical expansion); (ii) single-scan SABRE polarization using 1; (iii) single-scan SABRE polarization using 21; (iv) single-scan SABRE polarization using d22-21. Peak at ca. 254 ppm is attributed to equatorially bound pyridine-15N in the active catalyst11. Inset: Single-scan 15N NMR spectrum of 15NH4Cl (5.0 M) in D2O. b 13C NMR spectra of G (20 mM) using indicated [IrCl(COD)(NHC)] (5 mM) and the conditions: (v) thermal polarization visible after 64 scans (×8 vertical expansion); (vi) single-scan SABRE polarization using 1; (vii) single-scan SABRE polarization using 16, (vii) single-scan SABRE polarization using d34-16; peaks are assigned as previously reported32. Measurements used 3 bar p-H2
