Microcanonical kinetics of water-mediated proton transfer in microhydrated 4-aminobenzoic acid.

Isolated cluster systems can help to elucidate the molecular level description of water-mediated proton transfer. Protonation of neutral 4-aminobenzoic acid (4ABA) occurs at the acid (O-protomer) and amine (N-protomer) functionalities, yielding two distinct species with relative energies dependent on the degree of hydration. Here, we measured the rates of intramolecular proton transfer in 4ABAH+·(H2O)6 ions upon protomer-selective vibrational excitation of initially cold (6 K) cluster ions isolated in a cryogenic ion trap. Interconversion rates were observed on the microsecond time scale. These results quantify the kinetics of proton transfers in the context of a closed, finite system at well-defined internal energies and therefore provide experimental benchmarks for theoretical efforts that are being developed to treat relatively slow, highly cooperative solvent-mediated chemical processes.

• Publication year

  2025

• Venue

  Science

• Publication date

  2025-09-11

• Fields of study

  Medicine, Chemistry

• Identifiers
  DOI 10.1126/science.ady1723PMID 40934335
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

• The Onset for Vibrationally Induced, Intramolecular Proton Transfer at Three Water Molecules in Microhydrated 4-Aminobenzoic Acid.

  2025cited by this paper
• Transition from vehicle to Grotthuss proton transfer in a nanosized flask: cryogenic ion spectroscopy of protonated p-aminobenzoic acid solvated with D2O

  2024cited by this paper
• Observation of Slow Eigen-Zundel Interconversion in H+(H2O)6 Clusters upon Isomer-Selective Vibrational Excitation and Buffer Gas Cooling in a Cryogenic Ion Trap.

  2023cited by this paper
• Dissecting the Ultrafast Stepwise Bidirectional Proton Relay in a Blue-Light Photoreceptor.

  2023cited by this paper
• A Covalent Organic Framework as a Long-life and High-Rate Anode Suitable for Both Aqueous Acidic and Alkaline Batteries.

  2023cited by this paper
• Tracking the Delocalized Proton in Concerted Proton Transfer in Bulk Water.

  2023cited by this paper
• Proton-Conductive Supramolecular Hydrogen-Bonded Organic Superstructures for High-Performance Zinc-Organic Batteries.

  2023cited by this paper
• Proton Transport in Perfluorinated Ionomer Simulated by Machine-Learned Interatomic Potential.

  2023cited by this paper
• Microhydration of the metastable N-protomer of 4-aminobenzoic acid by condensation at 80 K: H/D exchange without conversion to the more stable O-protomer.

  2022cited by this paper
• Hydration-induced protomer switching in p-aminobenzoic acid studied by cold double ion trap infrared spectroscopy.

  2022cited by this paper
• Tools for analyzing protonation states and for tracing proton transfer pathways with examples from the Rb. sphaeroides photosynthetic reaction centers

  2022cited by this paper
• From Local Covalent Bonding to Extended Electric Field Interactions in Proton Hydration

  2022cited by this paper
• Hydroxide Ion Mechanism for Long-Range Proton Pumping in the Third Proton Transfer of Bacteriorhodopsin.

  2022cited by this paper
• p-Aminobenzoic acid protonation dynamics in an evaporating droplet by ab initio molecular dynamics.

  2021cited by this paper
• Unveiling Zwitterionization of Glycine in the Microhydration Limit

  2021cited by this paper
• Vibrational spectroscopy of the cryogenically cooled O- and N-protomers of 4-Aminobenzoic acid: Tag effects, isotopic labels, and identification of the E,Z isomer of the O-protomer.

  2020cited by this paper
• Tracking the Structural Evolution of 4-Aminobenzoic Acid in the Transition from Solution to the Gas Phase.

  2020cited by this paper
• Infrared Population Transfer Spectroscopy of Cryo-Cooled Ions: Quantitative Tests of the Effects of Collisional Cooling on the Room Temperature Conformer Populations.

  2018cited by this paper
• Effects of ESI conditions on kinetic trapping of the solution-phase protonation isomer of p-aminobenzoic acid in the gas phase.

  2017cited by this paper
• Vibrational Characterization of Microsolvated Electrocatalytic Water Oxidation Intermediate: [Ru(tpy)(bpy)(OH)]2+(H2O)0-4.

  2017cited by this paper
• Large-amplitude transfer motion of hydrated excess protons mapped by ultrafast 2D IR spectroscopy

  2017cited by this paper
• Experiment and theory confirm that UV laser photodissociation spectroscopy can distinguish protomers formed via electrospray.

  2017cited by this paper
• The impact of environment and resonance effects on the site of protonation of aminobenzoic acid derivatives.

  2016cited by this paper
• IR-induced conformational isomerization of a helical peptide in a cold ion trap.

  2016cited by this paper
• Ultrafast 2D IR spectroscopy of the excess proton in liquid water

  2015cited by this paper
• A dual cryogenic ion trap spectrometer for the formation and characterization of solvated ionic clusters.

  2015cited by this paper
• UV photodissociation spectroscopy of cryogenically cooled gas phase host-guest complex ions of crown ethers.

  2015cited by this paper
• New Method for Double-Resonance Spectroscopy in a Cold Quadrupole Ion Trap and Its Application to UV-UV Hole-Burning Spectroscopy of Protonated Adenine Dimer.

  2014cited by this paper
• Where's the charge? Protonation sites in gaseous ions change with hydration.

  2012cited by this paper
• Proton transfer via a transient linear water-molecule chain in a membrane protein

  2011cited by this paper
• Gas-phase versus liquid-phase structures by electrospray ionization mass spectrometry.

  2009cited by this paper
• Development of a low-temperature photoelectron spectroscopy instrument using an electrospray ion source and a cryogenically controlled ion trap.

  2008cited by this paper
• Ultrafast vibrational and structural dynamics of the proton in liquid water.

  2006cited by this paper
• Picosecond time-resolved study on the intramolecular vibrational energy redistribution of NH stretching vibration of jet-cooled aniline and its isotopomer

  2006cited by this paper
• Temperature dependence of ion and water transport in perfluorinated ionomer membranes for fuel cells.

  2005cited by this paper
• Thermodynamics of Macroscopic and Microscopic Proton Ionization from Protonated 4-Aminobenzoic Acid in Aqueous Solution from 298.15 to 393.15 K

  2000cited by this paper
• Vibrational Energy Flow in Highly Excited Molecules: Role of Intramolecular Vibrational Redistribution

  1996cited by this paper
• Aniline‐CH4S1 vibrational dynamics studied with picosecond photoelectron spectroscopy

  1993cited by this paper
• The Ultraviolet Absorption Spectra and Resonance in Benzene Derivatives—Sulfanilamide, Metanilamide, p-Aminobenzoic Acid, Benzenesulfonamide, Benzoic Acid and Aniline

  1943cited by this paper
• Immeasurably fast reactions *

  year unknowncited by this paper

• Catalysis of Acetone Enolization by Nitrogen-Containing Ligands: An Infrared Spectroscopic Study of (CH3COCH3-X)+ Complexes (X = CH3CN, CH2CHCN, NH3).

  2026cites this paper