![]() ![]() A discussion of the relevance of these findings to the applications of MS-PCET in organic synthesis is also presented. Electron transfer is a process by which an electron moves from one atom or molecule to another. lows for precise control over the applied driving force, and each. Inverted region behavior, where the rate constant decreases as the reaction becomes more exoergic (i.e., as G 0 becomes more negative), has been observed. The mechanisms of proton-coupled electron transfers (PCETs), in which proton and electron transfers involve different molecular centers, is the object of active current attention in view of the role that such reactions play in many natural processes (1 3). Electron transfer articles from across Nature Portfolio. Proton-coupled electron transfer, hydrogen evolution, steric effects, interface. A rationalization for this observation is proposed based on the principle of non-perfect synchronization, wherein factors that serve to stabilize the product are only partially realized at the transition state. The driving force dependence of the rate constants for nonadiabatic electron transfer (ET), proton transfer (PT), and proton-coupled electron transfer (PCET) reactions are examined. However, the slope of the rate–driving force relationship deviated significantly from expectations based on Marcus theory. The rates constants for the PCET events were linearly correlated with their driving forces over a range of nearly 19 kcal/mol. These experiments confirm that these activations occur in a concerted fashion, wherein the proton and electron are transferred to the ketone substrate in a single elementary step. As both ATP and PMF are driving forces of protein translocation in vivo, acting at different stages of translocation (Schiebel et al. of driving force (AGO) on the reaction rate, effect of molecular parameters and of. Transporters in the phosphate proton symporter (PHS) family use a proton gradient as the driving force to import phosphate across the plasma membrane of plant cells and fungi. A simple method is described for simultaneously extracting both the hydrogen-bonding equilibrium constants and the rate constants for the PCET event from deconvolution of the luminescence quenching data. In addition to increasing the driving force for proton transfer, enhancing the basicity of the carboxylate also decreases the equilibrium proton donor-acceptor. Past and current developments in electron and proton transfer and in. ABSTRACT: Here we present a detailed kinetic study of the multisite proton-coupled electron transfer (MS-PCET) activations of aryl ketones using a variety of Brønsted acids and excited-state Ir(III)-based electron donors. ![]()
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