Hyperbird: A sensitivity-enhanced approach to collecting homonuclear-decoupled proton NMR spectra

Samples prepared following dissolution dynamic nuclear polarization (DNP) enable the detection of NMR spectra from low-g nuclei with outstanding sensitivity, yet have limited use for the enhancement of abundant species like ¹H nuclei. Small- and intermediate-sized molecules, however, show strong heteronuclear cross-relaxation effects: spontaneous processes with an inherent isotopic selectivity, whereby only the ¹³C-bonded protons receive a polarization enhancement. These effects are here combined with a recently developed method that delivers homonuclear-decoupled ¹H spectra in natural abundance samples based on heteronuclear couplings to these same, ¹³C-bonded nuclei. This results in the HyperBIRD methodology; a single-shot combination of these two effects that can simultaneously simplify and resolve complex, congested ¹H NMR spectra with many overlapping spin multiplets, while achieving 50-100 times sensitivity enhancements over conventional thermal counterparts.