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Binary Mixtures of Aprotic and Protic Ionic Liquids Demonstrate Synergistic Polarity Effect: An Unusual Observation

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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.

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Acknowledgements

SRT thanks CSIR, New Delhi, for awarding him a Senior Research Fellowship, while A.K. thanks DST, New Delhi, for awarding him a J.C. Bose National Fellowship (SR/S2/JCB-26/2009).

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Authors and Affiliations

  1. Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, 411008, India

    Sachin Thawarkar & Anil Kumar

  2. Centre for Materials for Electronic Technology, Panchwati, Pashan Road, Pune, 411008, India

    Nageshwar D. Khupse

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  1. Sachin Thawarkar
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  2. Nageshwar D. Khupse
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  3. Anil Kumar
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Correspondence to Anil Kumar.

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Thawarkar, S., Khupse, N.D. & Kumar, A. Binary Mixtures of Aprotic and Protic Ionic Liquids Demonstrate Synergistic Polarity Effect: An Unusual Observation. J Solution Chem 49, 210–221 (2020). https://doi.org/10.1007/s10953-020-00952-w

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