Aggregation Behavior of Octyl Viologen Di[bis(trifluoromethanesulfonyl)amide] in Nonpolar Solvents
Aggregation Behavior of Octyl Viologen Di[bis(trifluoromethanesulfonyl)amide] in Nonpolar Solvents
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DOI：
10.1021/jp808306r
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发表时间：
2008-12-25
影响因子：
3.3
通讯作者：
Saielli, Giacomo
中科院分区：
文献类型：
--
作者：
Marotta, Ester;Rastrelli, Federico;Saielli, Giacomo
研究了辛基紫精（OV）盐与疏水阴离子双（三氟甲磺酰基）酰胺（Tf ~ 2N ~-）在非极性溶剂中的聚集行为。H-1和F-19 NMR，ESI-MS和DFT计算表明，在甲苯，苯和氯仿中形成大的聚集体，其中盐是高度可溶的。聚集体的寿命足够长，可以通过H-1和F-19 NMR光谱作为独立的物种与较小的中性OV（Tf 2N）（2）簇一起被检测到。这种行为与通常NMR检测到的平衡完全不同，通常仅观察到平均信号。尽管Tf 2N 2具有众所周知的低配位能力，但在甲苯和氯仿溶液的ESI-MS光谱中也观察到大的聚集体。有人建议，大的聚集体的结构模仿的热致近晶相，该系统表现出接近室温。
The aggregation behavior in nonpolar solvents of the octyl viologen (OV) salt with the hydrophobic anion bis(trifluoromethanesulfonyl)amide (Tf2N-) has been investigated. H-1 and F-19 NMR, ESI-MS and DFT calculations suggest that large aggregates are formed in toluene, benzene and chloroform, where the salt is highly soluble. The lifetime of the aggregates is long enough to be detected as independent species by H-1 and F-19 NMR spectroscopy, together with the smaller neutral OV(Tf2N)(2) cluster. This behavior is quite at variance with usual NMR detected equilibria where only average signals are generally observed. Large aggregates are also observed in ESI-MS spectra of toluene and chloroform solutions despite the well-known low-coordinating ability of Tf2N2. It is suggested that the structure of the large aggregates mimics the thermotropic smectic phase that this system exhibits near room temperature.