In this communication, we demonstrate the solute–solvent and solvent–solvent interactions in the binary mixtures of two aprotic ionic liquids, namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, with the protic ionic liquid 1-methylimidazolium acetate. The synergistic effects as expressed by the solvatochromic parameter are noted. This observation is in contrast to the mixing of protic ionic liquids 1-methylpyrrolidium acetate and 4-methylmorpholine acetate with 1-methylimidazolium acetate, respectively. It appears that the synergistic effects in the binary mixtures of aprotic and protic ionic liquids are caused by the formation of hydrogen bonds, since cations are dominant H-bond donors while anions are dominant H-bond acceptors. Preferential solvation models are used to describe the solute–solvent interactions in the binary ionic liquid mixtures.

中文翻译：

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非质子和质子离子液体的二元混合物表现出协同极性效应：一个不寻常的观察

在这次交流中，我们展示了两种非质子离子液体的二元混合物中的溶质 - 溶剂和溶剂 - 溶剂相互作用，即 1-丁基-3-甲基咪唑鎓双（三氟甲基磺酰基）亚胺和 1-丁基-1-甲基吡咯烷鎓双（三氟甲基磺酰基）酰亚胺，质子离子液体 1-甲基咪唑醋酸盐。注意到由溶剂化变色参数表示的协同效应。这一观察结果与质子离子液体 1-甲基吡咯鎓乙酸盐和 4-甲基吗啉乙酸盐分别与 1-甲基咪唑鎓乙酸盐的混合形成对比。非质子和质子离子液体的二元混合物中的协同效应似乎是由氢键的形成引起的，因为阳离子是主要的 H 键供体，而阴离子是主要的 H 键受体。