Quantifying the effects of quadrupolar sinks via 15N relaxation dynamics in metronidazoles hyperpolarized via SABRE-SHEATH

N-15 spin-lattice relaxation dynamics in metronidazole-N-15(3) and metronidazole-N-15(2) isotopologues are studied for rational design of N-15-enriched biomolecules for signal amplification by reversible exchange in microtesla fields. N-15 relaxation dynamics mapping reveals the deleterious effects of interactions with the polarization transfer catalyst and a quadrupolar N-14 nucleus within the spin-relayed N-15-N-15 network.