Fast Acquisition of Proton‐Detected HETCOR Solid‐State NMR Spectra of Quadrupolar Nuclei and Rapid Measurement of NH Bond Lengths by Frequency Selective HMQC and RESPDOR Pulse Sequences
Fast Acquisition of Proton‐Detected HETCOR Solid‐State NMR Spectra of Quadrupolar Nuclei and Rapid Measurement of NH Bond Lengths by Frequency Selective HMQC and RESPDOR Pulse Sequences
复制标题
快速采集质子检测到的四极核 HETCOR 固态 NMR 谱，并通过频率选择性 HMQC 和 RESPDOR 脉冲序列快速测量 NH 键长
DOI：
10.1002/chem.202000390
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Rossini, Aaron J.
中科院分区：
文献类型：
--
作者：
Wijesekara, Anuradha V.;Venkatesh, Amrit;Lampkin, Bryan J.;VanVeller, Brett;Lubach, Joseph W.;Nagapudi, Karthik;Hung, Ivan;Gor'kov, Peter L.;Gan, Zhehong;Rossini, Aaron J.
演示了快速魔角旋转（MAS）、频率选择（FS）异质多重量子相干（HMQC）实验，其功能类似于SOFAST HMQC NMR实验。快速MAS可实现1H固态NMR信号的高效FS激发。选择性激发和观察可消除1H磁化，从而显著缩短最佳扫描间延迟。偶极和标量1H {14 N} FS HMQC固态NMR实验与常规1H {14 N} HMQC固态NMR实验相比，常规实验时间减少4至9倍。1H {14 N} FS共振-回波饱和-脉冲双共振（CIDDOR）允许在几分钟内获得偶极退相曲线，使得能够快速测定NH偶极耦合常数和核间距。1H {14 N} FSPRADDOR用于将多组分活性药物成分（API）指定为盐或共晶。FS HMQC还分别为17 O标记的Fmoc-丙氨酸和组氨酸盐酸盐一水合物的1H {17 O}和1H {35 Cl} HMQC实验提供了增强的灵敏度。FS HMQC和FS HMDOR实验将提供从材料中获得有价值的结构约束的机会，这些材料由于不利的弛豫时间或感兴趣的核的稀释而具有挑战性。
Fast magic‐angle spinning (MAS), frequency selective (FS) heteronuclear multiple quantum coherence (HMQC) experiments which function in an analogous manner to solution SOFAST HMQC NMR experiments, are demonstrated. Fast MAS enables efficient FS excitation of1H solid‐state NMR signals. Selective excitation and observation preserves1H magnetization, leading to a significant shortening of the optimal inter‐scan delay. Dipolar and scalar1H{14N} FS HMQC solid‐state NMR experiments routinely provide 4‐ to 9‐fold reductions in experiment times as compared to conventional1H{14N} HMQC solid‐state NMR experiments.1H{14N} FS resonance‐echo saturation‐pulse double‐resonance (RESPDOR) allowed dipolar dephasing curves to be obtained in minutes, enabling the rapid determination of NH dipolar coupling constants and internuclear distances.1H{14N} FS RESPDOR was used to assign multicomponent active pharmaceutical ingredients (APIs) as salts or cocrystals. FS HMQC also provided enhanced sensitivity for1H{17O} and1H{35Cl} HMQC experiments on17O‐labeled Fmoc‐alanine and histidine hydrochloride monohydrate, respectively. FS HMQC and FS RESPDOR experiments will provide access to valuable structural constraints from materials that are challenging to study due to unfavorable relaxation times or dilution of the nuclei of interest.