Unique combination of ionic conductivity and anisotropic physical properties in ionic liquid crystals leads to new dynamic properties exploited in modern technological applications. Structural and dynamics information at atomic level for molecules and ions in mesophases can be obtained by nuclear magnetic resonance (NMR) spectroscopy through the measurements of dipole–dipole spin couplings. While 13C–1H and 15N–1H dipolar NMR spectra can be routinely acquired in samples with natural isotopic abundance, recording 15N–13C dipolar NMR spectra is challenging because of the unfavourable combination of two rare isotopes. In the present study, an approach to measure 15N–13C dipole-dipole NMR spectra in static liquid crystalline samples with natural abundance is introduced. We demonstrate that well-resolved spectra can be recorded within 10 h of experimental time using a conventional NMR probe and a moderately strong magnetic field. The technique is applied to a thermotropic smectic mesophase formed by an ionic liquid with imidazolium-based organic cation.

中文翻译：

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热致离子液体近晶中间相中的 15N-13C 偶极耦合

离子液晶中离子电导率和各向异性物理特性的独特组合导致了现代技术应用中开发的新动态特性。中间相中分子和离子的原子级结构和动力学信息可以通过核磁共振 (NMR) 光谱法通过偶极-偶极自旋耦合的测量获得。虽然 13C–1H 和 15N–1H 偶极 NMR 谱可以在具有天然同位素丰度的样品中常规获得，但由于两种稀有同位素的不利组合，记录 15N–13C 偶极 NMR 谱具有挑战性。在本研究中，介绍了一种测量具有天然丰度的静态液晶样品中 15N–13C 偶极-偶极 NMR 光谱的方法。我们证明，使用传统的 NMR 探针和中等强度的磁场，可以在实验时间的 10 小时内记录分辨率良好的光谱。该技术应用于由具有咪唑鎓基有机阳离子的离子液体形成的热致近晶中间相。