Fig. 4
Relaxation effects and SABRE performance of catalysts 1−21. a T1 relaxation times for H-2 (solid block) and H-5 (dashed) of free A (1 eq.) when present with [Ir(H)2(NHC)(A)3]Cl (5 mM) and 3 bar H2 in methanol-d4 at 9.4 T. b SABRE polarization of the H-2 (solid block) and H-5 (dashed) resonances of A in the same sample after SABRE transfer at 65 G under 3 bar p-H2. Data are presented as a function of 1−21, and colour coded according to changes in the ortho (red), para (blue) and imidazole (green) substituents
