Related Experiment Video
Updated: Jun 3, 2025
11:00
Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
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pKa Matching Enables Quantum Proton Delocalization in Acid-1-Methylimidazole Binary Mixtures
Rui Zhang1, Dylan Ye2, Anit Gurung3
1Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States.
Journal of Chemical Information and Modeling
|January 8, 2025
Summary
Short hydrogen bonds (SHBs) form in nonaqueous mixtures when acid-base pKa values match. This matching drives proton delocalization, offering new possibilities for advanced materials.
Area of Science:
- Physical Chemistry
- Chemical Physics
- Materials Science
Background:
- Short hydrogen bonds (SHBs), with donor-acceptor distances < 2.7 Å, are common in condensed phases.
- Quantum effects in nonaqueous acetic acid/1-methylimidazole mixtures enable proton delocalization via SHBs.
Purpose of the Study:
- To investigate conditions favoring SHB formation in binary acid-base mixtures.
- To establish pKa difference as a key determinant for SHB formation in nonaqueous systems.
Main Methods:
- Utilized electronic structure calculations to analyze 97 acid-1-methylimidazole pairs in DMSO.
- Employed first-principles simulations and infrared spectroscopy to confirm SHB formation and proton delocalization.
Main Results:
- Confirmed SHB formation and proton delocalization in benzoic acid-MIm and salicylic acid-MIm mixtures.
- Demonstrated that pKa matching significantly alters proton behavior, shifting interactions from transfer to quantum delocalization.
Conclusions:
- pKa matching is crucial for controlling proton behavior in nonaqueous systems.
- DMSO is a viable solvent for assessing pKa matching, highlighting the role of hydrogen bond networks.
- Findings offer insights for designing organic mixtures utilizing SHBs for advanced materials.
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