Figure 1.

(A) ¹⁵N NMR spectrum of a 0.25 M ¹⁵N-neurine substrate in the presence of 1.0% Rh/TiO₂ before reaction with p-H₂ in D₂O, recorded with eight scans and a 30 s repetition delay; no signal of reactant is observed at 58 ppm under these conditions. ¹⁵N NMR spectrum of the hyperpolarized product using the same acquisition parameters as those used for spectrum acquisition shown in (A) but taken with 1 scan after transfer of spin order to ¹⁵N, achieved with 30 s 50%-enriched p-H₂ bubbling inside of the magnetic shield. (C) Same as (B) but with hydrogenation occurring over 23.2% Rh/TiO₂. HP ¹⁵N spectra are shown with an absorptive phase (i.e., sharing the same phase as a thermally polarized ¹⁵N sample); note that the field cycling was not optimized for polarization transfer.