The indirect NMR detection of quadrupolar nuclei in solids under magic-angle spinning (MAS) is possible with the through-space HMQC (heteronuclear multiple-quantum coherence) scheme incorporating the TRAPDOR (transfer of population in double-resonance) dipolar recoupling. This sequence, called T-HMQC, exhibits limited t₁-noise. In this contribution, with the help of numerical simulations of spin dynamics, we show that most of the time, the fastest coherence transfer in the T-HMQC scheme is achieved when TRAPDOR recoupling employs the highest radiofrequency (rf) field compatible with the probe specifications. We also demonstrate how the indirect detection of the triple-quantum (3Q) coherences of spin-3/2 quadrupolar nuclei in solids improves the spectral resolution for these isotopes. The sequence is then called T-HMQC₃. We demonstrate the gain in resolution provided by this sequence for the indirect proton detection of ³⁵Cl nuclei in l-histidine∙HCl and l-cysteine∙HCl, as well as that of ²³Na isotope in NaH₂PO₄. These experiments indicate that the gain in resolution depends on the relative values of the chemical and quadrupolar-induced shifts (QIS) for the different spin-3/2 species. In the case of NaH₂PO₄, we show that the transfer efficiency of the T-HMQC₃ sequence employing an rf-field of 80 kHz with a MAS frequency of 62.5 kHz reaches 75% of that of the t₁-noise eliminated (TONE) dipolar-mediated HMQC (D-HMQC) scheme.

在魔角自旋 (MAS) 下对固体中四极核的间接 NMR 检测是可能的，通过空间 HMQC（异核多量子相干）方案结合了 TRAPDOR（双共振中的人口转移）偶极再耦合。这个称为 T-HMQC 的序列展示了有限的t ₁-噪音。在这一贡献中，借助自旋动力学的数值模拟，我们表明，大多数时候，当 TRAPDOR 重新耦合采用与探头规格兼容的最高射频 (rf) 场时，T-HMQC 方案中最快的相干转移是实现的. 我们还展示了间接检测固体中自旋 3/2 四极核的三重量子 (3Q) 相干性如何提高这些同位素的光谱分辨率。然后将该序列称为T-HMQC ₃。我们展示了该序列为 l -组氨酸∙HCl 和 l -半胱氨酸∙HCl 中的35 Cl核^以及NaH 2 中的₂₃ ^Na同位素的间接质子检测提供的分辨率增益采购订单₄。这些实验表明，分辨率的提高取决于不同自旋 3/2 物种的化学和四极诱导位移 (QIS) 的相对值。在 NaH ₂ PO ₄的情况下，我们表明采用 80 kHz 射频场和 62.5 kHz MAS 频率的T-HMQC _{3序列的传输效率达到}t ₁ -噪声消除的传输效率的 75%（ TONE) 偶极介导的 HMQC ( D -HMQC) 方案。