The hydrated electron, e-(aq), is a potent reducing agent and a prototypical quantum solute. Reactions of e-(aq) often involve a contact pair comprised of a molecule and electron that are hydrated within a single sphere. However, a molecular-level understanding of the solvent-driven coordinate that links the contact pair to the free dissociated e-(aq) remains elusive. Here, we study this coordinate by kinetically trapping representative metastable intermediates as gas-phase clusters and probing them using photoelectron spectroscopy. We apply this methodology to uracil-water anion clusters, where key intermediates are identified with supporting quantum chemical calculations. Just a single water molecule drives the parent molecule and non-valence electron apart, thereby inhibiting geminate recombination to form the more stable valence-bound uracil anion. The electron-water binding is akin to bare water cluster anions, highlighting the link to larger clusters and e-(aq). Our results provide a molecular-level view of quantum solute hydration and, more broadly, of how water-driven electron-transfer reactions proceed.

Department of Chemistry Durham University Durham United Kingdom

J Heyrovský Institute of Physical Chemistry Czech Academy of Sciences Prague 8 Czech Republic

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Kevan, L. Solvated electron structure in glassy matrixes. DOI

Larsen, R. E., Glover, W. J. & Schwartz, B. J. Does the hydrated electron occupy a cavity? PubMed DOI

Kumar, A., Walker, J. A., Bartels, D. M. & Sevilla, M. D. A simple ab initio model for the hydrated electron that matches experiment. PubMed DOI PMC

Herbert, J. M. Structure of the aqueous electron. PubMed DOI

Bragg, A. E., Verlet, J. R. R., Kammrath, A., Cheshnovsky, O. & Neumark, D. M. Hydrated electron dynamics: From clusters to bulk. PubMed DOI

Elkins, M. H., Williams, H. L., Shreve, A. T. & Neumark, D. M. Relaxation mechanism of the hydrated electron. PubMed DOI

Garrett, B. C. et al. Role of water in electron-initiated processes and radical chemistry:  Issues and scientific advances. PubMed DOI

Siefermann, K. R. et al. Binding energies, lifetimes and implications of bulk and interface solvated electrons in water. PubMed DOI

Matsuzaki, K. et al. Partially hydrated electrons at the air/water interface observed by UV-excited time-resolved heterodyne-detected vibrational sum frequency generationspectroscopy. PubMed DOI

Herbert, J. M. & Coons, M. P. The hydrated electron. PubMed DOI

Jordan, C. J. C., Coons, M. P., Herbert, J. M. & Verlet, J. R. R. Spectroscopy and dynamics of the hydrated electron at the water/air interface. PubMed DOI PMC

Jortner, J., Ottolenghi, M. & Stein, G. On the photochemistry of aqueous solutions of chloride, bromide, and iodide ions. DOI

Staib, A. & Borgis, D. Reaction pathways in the photodetachment of an electron from aqueous chloride: A quantum molecular dynamics study. DOI

Chen, X. & Bradforth, S. E. The ultrafast dynamics of photodetachment. PubMed DOI

Messina, F., Bräm, O., Cannizzo, A. & Chergui, M. Real-time observation of the charge transfer to solvent dynamics. PubMed DOI

Carter-Fenk, K., Johnson, B. A., Herbert, J. M., Schenter, G. K. & Mundy, C. J. Birth of the hydrated electron via charge-transfer-to-solvent excitation of aqueous iodide. PubMed DOI

Lan, J., Chergui, M. & Pasquarello, A. Dynamics of the charge transfer to solvent process in aqueous iodide. PubMed DOI PMC

Sheu, W.-S. & Rossky, P. J. Electronic and solvent relaxation dynamics of a photoexcited aqueous halide. DOI

Buxton, G. V., Greenstock, C. L., Helman, W. P. & Ross, A. B. Critical Review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals (⋅OH/⋅O− in Aqueous Solution. DOI

Kunin, A. & Neumark, D. M. Time-resolved radiation chemistry: femtosecond photoelectron spectroscopy of electron attachment and photodissociation dynamics in iodide–nucleobase clusters. PubMed DOI

Cooper, G. A., Clarke, C. J. & Verlet, J. R. R. Low-energy shape resonances of a nucleobase in water. PubMed DOI PMC

Falcone, J. M., Becker, D., Sevilla, M. D. & Swarts, S. G. Products of the reactions of the dry and aqueous electron with hydrated DNA: hydrogen and 5,6-dihydropyrimidines. DOI

Boudaïffa, B., Cloutier, P., Hunting, D., Huels, M. A. & Sanche, L. Resonant formation of DNA strand breaks by low-energy (3 to 20 eV) electrons. PubMed DOI

Alizadeh, E., Orlando, T. M. & Sanche, L. Biomolecular damage induced by ionizing radiation: The Direct and Indirect Effects of Low-Energy Electrons on DNA. PubMed DOI

Schiedt, J., Weinkauf, R., Neumark, D. M. & Schlag, E. W. Anion spectroscopy of uracil, thymine and the amino-oxo and amino-hydroxy tautomers of cytosine and their water clusters. DOI

Desfrançois, C., Periquet, V., Bouteiller, Y. & Schermann, J. P. Valence and dipole binding of electrons to Uracil. DOI

Fermi, E. & Teller, E. The capture of negative mesotrons in matter. DOI

Jordan, K. D. & Wang, F. Theory of dipole-bound anions. PubMed DOI

Eustis, S., Wang, D., Lyapustina, S. & Bowen, K. H. Photoelectron spectroscopy of hydrated adenine anions. PubMed DOI

Cooper, J. & Zare, R. N. Angular distribution of photoelectrons. DOI

Sanov, A. Laboratory-frame photoelectron angular distributions in anion photodetachment: Insight into electronic structure and intermolecular interactions. PubMed DOI

Simons, J. Ejecting electrons from molecular anions via shine, shake/rattle, and roll. PubMed DOI

Verlet, J. R. R., Anstöter, C. S., Bull, J. N. & Rogers, J. P. Role of nonvalence states in the ultrafast dynamics of isolated anions. PubMed DOI PMC

Coe, J. V. et al. Photoelectron spectroscopy of hydrated electron cluster anions, (H2O)−n=2–69. DOI

Verlet, J. R. R., Bragg, A. E., Kammrath, A., Cheshnovsky, O. & Neumark, D. M. Observation of large water-cluster anions with surface-bound excess electrons. PubMed DOI

Coe, J. V., Arnold, S. T., Eaton, J. G., Lee, G. H. & Bowen, K. H. Photoelectron spectra of hydrated electron clusters: Fitting line shapes and grouping isomers. PubMed DOI

Coe, J. V., Williams, S. M. & Bowen, K. H. Photoelectron spectra of hydrated electron clusters vs. cluster size: connecting to bulk. DOI

Ma, L., Majer, K., Chirot, F. & von Issendorff, B. Low temperature photoelectron spectra of water cluster anions. PubMed DOI

Lietard, A. & Verlet, J. R. R. Selectivity in electron attachment to water clusters. PubMed DOI

Bailey, C. G., Dessent, C. E. H., Johnson, M. A. & Bowen, K. H. Vibronic effects in the photon energy‐dependent photoelectron spectra of the CH3CN− dipole‐bound anion. DOI

Sindelka, M. et al. Calculation of the photodetachment cross sections of the HCN− and HNC− dipole-bound anions as described by a one-electron Drude model. PubMed DOI

Wigner, E. P. On the behavior of cross sections near thresholds. DOI

Hendricks, J. H., Lyapustina, S. A., de Clercq, H. L. & Bowen, K. H. The dipole bound-to-covalent anion transformation in uracil. DOI

Clarke, C. J., Burrow, E. M. & Verlet, J. R. R. The valence electron affinity of uracil determined by anion cluster photoelectron spectroscopy. PubMed DOI

Slimak, S. & Jordan, K. D. Binding of an electron by a finite fixed dipole. PubMed DOI

Anstöter, C. S. & Matsika, S. Understanding the interplay between the nonvalence and valence states of the Uracil Anion upon Monohydration. PubMed DOI

Jortner, J. Cluster size effects. DOI

Markovich, G., Pollack, S., Giniger, R. & Cheshnovsky, O. Photoelectron spectroscopy of Cl−, Br−, and I− solvated in water clusters. DOI

Hammer, N. I. et al. How do small water clusters bind an excess electron? PubMed DOI

Hammer, N. I., Roscioli, J. R. & Johnson, M. A. Identification of two distinct electron binding motifs in the anionic water clusters:  A vibrational spectroscopic study of the (H2O)6- isomers. PubMed DOI

Ayotte, P. & Johnson, M. A. Electronic absorption spectra of size-selected hydrated electron clusters: (H2O)n−, n=6–50. DOI

Uhlig, F., Marsalek, O. & Jungwirth, P. Unraveling the complex nature of the hydrated electron. PubMed DOI

Anusiewicz, I., Skurski, P. & Simons, J. Fate of dipole-bound anion states when hydrated. PubMed DOI

Marcus, R. A. Chemical and electrochemical electron-transfer theory. DOI

Castleman, A. W. & Keesee, R. G. Gas-phase clusters: Spanning the states of matter. PubMed DOI

Coe, J. V. Connecting cluster anion properties to bulk: Ion solvation free energy trends with cluster size and the surface vs internal nature of iodide in water clusters. DOI

Luckhaus, D., Yamamoto, Y., Suzuki, T. & Signorell, R. Genuine binding energy of the hydrated electron. PubMed DOI PMC

Majer, K., Ma, L. & von Issendorff, B. Photoelectron spectroscopy of large water cluster anions. PubMed DOI

Okuyama, H., Suzuki, Y.-I., Karashima, S. & Suzuki, T. Charge-transfer-to-solvent reactions from I− to water, methanol, and ethanol studied by time-resolved photoelectron spectroscopy of liquids. PubMed DOI

Even, U. “The Even-Lavie valve as a source for high intensity supersonic beam”. DOI

Rogers, J. P., Anstöter, C. S., Bull, J. N., Curchod, B. F. E. & Verlet, J. R. R. Photoelectron spectroscopy of the hexafluorobenzene cluster anions: (C6F6)n– (n = 1–5) and I–(C6F6). PubMed DOI

Dick, B. MELEXIR: maximum entropy Legendre expanded image reconstruction. A fast and efficient method for the analysis of velocity map imaging or photoelectron imaging data. PubMed DOI

Kendall, R. A., Dunning, T. H. Jr. & Harrison, R. J. Electron affinities of the first‐row atoms revisited. Systematic basis sets and wave functions. DOI

Yanai, T., Tew, D. P. & Handy, N. C. A new hybrid exchange–correlation functional using the Coulomb-attenuating method (CAM-B3LYP). DOI

Raghavachari, K., Trucks, G. W., Pople, J. A. & Head-Gordon, M. A fifth-order perturbation comparison of electron correlation theories. DOI

Frisch, M. J. et al. Gaussian 16, Revision C.01. Gaussian, Inc. (2016).

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