A recent paper on solid-state 13 C nuclear magnetic resonance in graphitic materials reports on the difficulties with the interpretation of the spectra and presents alternative methods to obtain informative experimental data. Therein, special emphasis is placed on the role of dipole–dipole interactions in the case of 13 C-enriched samples and on the assignment of the 13 C spectral components beyond the common “graphitic range”. Here, we show that the consideration of the experimental conditions, namely, the speed of magic angle spinning, plays a more important role in the data interpretation. Further, we provide the experimental and theoretical evidences that the appearance of the 13 C resonances shifted upfield from the typical sp 2 -hybridized carbon range is not surprising, but rather exhibits a characteristic feature of the graphitic materials with specific morphology. Finally, we show that analysis of the anisotropy of the chemical shift tensor is informative even in the case of very broad 13 C spectra and supports the microscopy observations.

中文翻译：

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评“石墨材料固态13C核磁共振谱分析的难点和陷阱”

最近一篇关于石墨材料中固态 13 C 核磁共振的论文报告了光谱解释的困难，并提出了获取信息实验数据的替代方法。其中，特别强调偶极-偶极相互作用在富含 13 C 样品的情况下的作用以及超出常见“石墨范围”的 13 C 光谱成分的分配。在这里，我们表明对实验条件的考虑，即魔角旋转的速度，在数据解释中起着更重要的作用。此外，我们提供了实验和理论证据，表明 13 C 共振的出现从典型的 sp 2 -杂化碳范围向上场​​转移并不奇怪，而是表现出具有特定形态的石墨材料的特征。最后，我们表明，即使在非常宽的 13 C 光谱的情况下，化学位移张量的各向异性分析也能提供信息，并支持显微镜观察。