This study examines the formation of previously unreported crystalline phases of N-methoxyethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr_12O1TFSI). The melting point of pristine Pyr_12O1TFSI, determined by conductivity measurements, is between −20 and −17.5 °C. Formation of this crystalline phase is difficult and only occurs under specific conditions. Pyr_12O1TFSI readily forms 1:1 phases with both NaTFSI and Mg(TFSI)_2. The results of single crystal structure determinations are presented. The Na⁺ crystalline phase provides clear evidence that the Pyr_12O1⁺ cation can coordinate some metal ions, but this coordinative interaction does not occur with all metal cations, e.g., Mg²⁺, and in all states of matter, e.g., Na⁺-IL solutions. The TFSI^– ions are found in two different aggregate solvates in the Pyr_12O1TFSI:NaTFSI 1:1 phase and in contact ion pair and aggregate solvates in the Pyr_12O1TFSI:Mg(TFSI)₂ 1:1 phase. The Pyr_12O1TFSI:Mg(TFSI)₂ crystalline phase gives insight into the local structure of the liquid electrolyte, where it is likely that a maximum of approximately 30% of the total TFSI^– can likely be coordinated in a bridging geometry, and the rest are in a bidentate coordination geometry. This ratio is determined from both the crystal structure and the Raman spectroscopy results.

中文翻译：

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基于Pyr _12O1 TFSI的离子液体电解质的晶体配合物

这项研究检查了N-甲氧基乙基-N-甲基_吡咯烷鎓双（三氟甲磺酰基）酰亚胺（Pyr _12O1 TFSI）以前未报道的结晶相的形成。通过电导率测量确定的原始Pyr _12O1 TFSI的熔点在-20至-17.5°C之间。该结晶相的形成是困难的，并且仅在特定条件下发生。Pyr _12O1 TFSI容易与NaTFSI和Mg（TFSI）₂形成1：1的相。给出了单晶结构测定的结果。Na ⁺结晶相提供了明显的证据，表明Pyr _12O1 ⁺阳离子可以配位一些金属离子，但是这种配位相互作用不会在所有金属阳离子（例如Mg ²⁺）和所有物质状态（例如Na ⁺ -IL溶液）中发生。TFSI ^–离子存在于Pyr _12O1 TFSI：NaTFSI 1：1相的两个不同的聚集溶剂化物中，以及在Pyr _12O1 TFSI：Mg（TFSI）₂ 1：1相中的接触离子对和聚集溶剂化物中。Pyr _12O1 TFSI：Mg（TFSI）₂晶相可洞察液体电解质的局部结构，在该结构中，最大可能约占总TFSI的30％^–可以在桥接几何中进行协调，而其余则在双齿协调几何中进行协调。该比率由晶体结构和拉曼光谱结果确定。