When like-charged ions attract: How OH-defects influence the size and distribution of cationic clusters in ionic liquids

This study will probe the liquid nanostructures of mixtures of two ionic liquids, 4-(hydroxybutyl)pyridinium-bis(trifluorosulfonyl)-imide ([HOC4Py]NTf2) and pentylpyridinium-bis(trifluorosulfonyl)imide ([C5Py]NTf2), which are identical except that the alkyl chain of the former is terminated by OH and the latter by CH3. Hence, ion clustering is expected in [HOC4Py]NTf2 but not in [C5Py]NTf2, which will reveal the effect of the alcohol H-bonding unambiguously. We will determine how the defects of OH groups in the H-bond network will influence the cluster distribution and the most probable cluster structures. Furthermore, we will figure out how big the anion excess has to be to break down the bigger cation-cation-based aggregates into cation-anion monomers.

本研究将探究两种离子液体（ionic liquids）混合物的液态纳米结构，二者分别为4-(羟丁基)吡啶鎓双(三氟磺酰)亚胺（[HOC4Py]NTf2）与戊基吡啶鎓双(三氟磺酰)亚胺（[C5Py]NTf2），仅在烷基链末端官能团上存在差异：前者为羟基（OH），后者为甲基（CH3）。据此推测，[HOC4Py]NTf2体系中会形成离子团簇，而[C5Py]NTf2体系则不会，这一特性可用于清晰揭示醇羟基氢键（H-bonding）的作用效应。本研究将明确氢键网络中羟基缺陷对团簇分布与最可几团簇结构的影响机制。此外，本研究还将厘清阴离子过量需达到何种阈值，方能将基于阳离子-阳离子的大型聚集体拆解为阳离子-阴离子单体。