Fig. 4. (A) Natural abundance 13C NMR spectra following a single 90° pulse for (top) 10.28 M (neat) 4-methylpyridine (4096 scans in 52 hours, scaled by ×100), (middle, bottom) 156 mM 4-methylpyridine with 5.2 mM catalyst in methanol-d4 (1 scan in 15 s with SABRE hyperpolarization), presented in real (middle) and magnitude (bottom) modes. (B) 13C{1H} NMR spectra acquired at 1 T of (top) 10.28 M (neat) 4-methylpyridine (256 scans in 5 hours) and (bottom) 156 mM 4-methylpyridine with 5.2 mM catalyst in methanol-d4 (1 scan in 15 s with SABRE hyperpolarization and refocusing prior to signal acquisition, scaled by x8).
