Bowring, Miriam A. Bradshaw, Liam R. Parada, Giovanny A. Pollock, Timothy P. Fernández-Terán, Ricardo J. Kolmar, Scott S. Mercado, Brandon Q. Schlenker, Cody W. Gamelin, Daniel R. Mayer, James M. Activationless Multiple-Site Concerted Proton–Electron Tunneling The transfer of protons and electrons is key to energy conversion and storage, from photosynthesis to fuel cells. Increased understanding and control of these processes are needed. A new anthracene–phenol–pyridine molecular triad was designed to undergo fast photoinduced multiple-site concerted proton–electron transfer (MS-CPET), with the phenol moiety transferring an electron to the photoexcited anthracene and a proton to the pyridine. Fluorescence quenching and transient absorption experiments in solutions and glasses show rapid MS-CPET (3.2 × 10<sup>10</sup> s<sup>–1</sup> at 298 K). From 5.5 to 90 K, the reaction rate and kinetic isotope effect (KIE) are independent of temperature, with <i>zero</i> Arrhenius activation energy. From 145 to 350 K, there are only slight changes with temperature. This MS-CPET reaction thus occurs by tunneling of both the proton and electron, in different directions. Since the reaction proceeds without significant thermal activation energy, the rate constant indicates the magnitude of the electron/proton double tunneling probability. fuel cells;reaction proceeds;electron;tunneling probability;KIE;glasses show;energy conversion;MS-CPET reaction;proton;transfer;Arrhenius activation energy;photoexcited anthracene;phenol moiety;absorption experiments;90 K;Fluorescence quenching;reaction rate;298 K;350 K;isotope effect;photoinduced multiple-site;activation energy 2018-05-30
    https://acs.figshare.com/articles/journal_contribution/Activationless_Multiple-Site_Concerted_Proton_Electron_Tunneling/6474425
10.1021/jacs.8b04455.s001