A pulse radiolysis study on pyrrolidinium cation based ionic liquids is presented herein. Time-resolved absorption spectra for 1-methyl-1-propylpyrrolidinium dicyanamide (DCA) at 500 ns after the electron pulse show broad absorption bands at wavelengths below 440 nm and at 640 nm. In pyrrolidinium bis(trifluoromethylsulfonyl)imide (NTf₂) and tris(perfluoroethyl)trifluorophosphate (FAP) ILs, the transient absorption below 440 nm is much weaker. The absorption at 500 ns, which increases with wavelength from 500 nm to beyond 800 nm, was assigned to the tail of the solvated electron NIR absorption spectrum, since it disappears in the presence of N₂O. In the DCA IL, the presence of a reducing species was confirmed by the formation of pyrene radical anion. The difference in the transient species in the case of the DCA IL compared to other two ILs should be due to the anion, with cations being similar. In pseudohalide ILs such as DCA, radicals are formed by direct hole trapping by the anion (X^– + h⁺ → X^•), followed by addition to the parent anion. Prediction of the UV/vis absorption spectra of the dimer radical anion by computational calculation supports the experimental results. The oxidizing efficiency of (DCA)₂^•– and its reduction potential (E_{(DCA)2^•–/(2DCA^–)}) have been determined.

中文翻译：

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吡咯烷鎓二氰胺离子液体的脉冲辐射分解和计算研究：二聚体自由基阴离子的检测

本文介绍了基于吡咯烷鎓阳离子的离子液体的脉冲辐射分解研究。1-甲基-1-丙基吡咯烷鎓双氰胺（DCA）在电子脉冲后500 ns的时间分辨吸收光谱在440 nm以下和640 nm波长处显示宽吸收带。在吡咯烷鎓双（三氟甲基磺酰基）酰亚胺（NTf ₂）和三（全氟乙基）三氟磷酸酯（FAP）IL中，在440 nm以下的瞬态吸收要弱得多。在500 ns处的吸收随着波长从500 nm增加到超过800 nm而增加，该吸收被分配给溶剂化电子NIR吸收光谱的尾部，因为它在存在N _2时消失了。O.在DCA IL中，通过species自由基阴离子的形成证实了还原物质的存在。DCA IL与其他两个IL相比，瞬态物种的差异应归因于阴离子，阳离子相似。在假卤化物ILs（例如DCA）中，自由基是由阴离子（X ^– + h ⁺ →X ^•）直接捕获空穴，然后添加到母体阴离子中而形成的。通过计算计算预测二聚自由基阴离子的紫外/可见吸收光谱可支持实验结果。（DCA）₂ ^•–的氧化效率及其还原电位（E _{（DCA）2 ^•– /（2DCA ^–）}）已确定。