Efficient transfer of DNP‐enhanced ¹ H magnetization to half‐integer quadrupolar nuclei in solids at moderate spinning rate

We show herein how the proton magnetization enhanced by dynamic nuclear polarization (DNP) can be efficiently transferred at moderate magic-angle spinning (MAS) frequencies to half-integer quadrupolar nuclei, S ≥ 3/2, using Dipolar-mediated Refocused Insensitive Nuclei Enhanced Polarization Transfer (D-RINEPT) technique, in which a symmetry-based recoupling scheme built from adiabatic inversion 1H pulses reintroduces 1H–S dipolar couplings, while suppressing 1H–1H ones. The use of also improves robustness offsets and radiofrequency (rf)-field inhomogeneity. Furthermore, efficiency transfer is further improved composite continuous-wave irradiations between blocks, as well manipulating satellite transitions during first block. case large D-RINEPT variant with two on channel results an efficiency. compare here performances this new those its parent version single π pulses, PRESTO CPMAS transfers. This comparison performed simulations DNP-enhanced 27Al, 95Mo, 17O NMR experiments isotopically unmodified γ-alumina, hydrated titania-supported MoO3, Mg(OH)2, l-histidine·HCl·H2O. introduced RINEPT method outperforms existing methods, both terms rf-field inhomogeneity offset.