Adiabatic Proton-Coupled Charge-Transfer Reactions and Photochemistry of N, N-Dimethyl-3-arylpropan-1-ammonium Salts PDF Download

Author: Trevor Safko
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 282

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Book Description
The coupling of proton and electron transfers in concerted or sequential processes is of central importance to many biochemical and catalytic reactions. In this context, proton-coupled electron transfer reactions are typically described electrochemically, whereby the transfer of a proton is coordinated to a change in the oxidation state of the constituent donor/acceptor pairs. In the excited-state, intermolecular proton transfers are often facilitated through a redistribution of electron-density (charge-transfer) along the proton-transfer reaction coordinate without a corresponding change in the oxidation state of the donor/acceptor pair. Distinguishing charge-transfer from full electron-transfer reactions along the excited-state potential energy surface has received increased attention as advancements in engineering allow for the interrogation of the fastest molecular events. This dissertation seeks primarily to examine the confluence of charge-transfer, electron-transfer, and proton-transfer reactions which occur adiabatically in the excited-states of N, N-dimethyl-3-arylpropan-1-ammonium salts in solution. For these compounds, an excited-state intermolecular proton-transfer to the solvent is accompanied by intramolecular charge-transfer and the formation of either an emissive exciplex or a transient solvent-separated ion pair. The various electronic configurations have been interrogated through an array of spectroscopic techniques in order to more thoroughly understand the convergence of thermodynamic and kinetic factors affecting the proposed mechanism. In this regard, a range of temperatures, solvents, counterions, and lumophores have been explored. In addition, the ground-state equilibrium has been investigated through targeted theoretical calculations and experiments. The summation of these experiments provide unique insights into a class of novel exciplex-mediated proton-coupled charge-transfer reactions.