Light Driven Electron Transfer in Methylbipyridine/Phenol Complexes Is Not Proton Coupled

The pursuit of systems that undergo optical electron proton transfer (photo-EPT) is very attractive, due to the wealth of information contained in the absorption spectra of such complexes. However, separating photo-EPT transitions from conventional charge transfer states remains a major challenge. In this study, we show that optical charge transfer in a complex between 4-methoxyphenol and N-methyl-4,4′-bipyridyl, previously assigned to occur through photo-EPT involving a hydrogen bond between the reactants (Gagliardi, C. J.;; Wang, L.;; Dongare, P.;; Brennaman, M. K.;; Papanikolas, J. M.;; Meyer, T. J.;; Thompson, D. W. Proc. Natl. Acad. Sci. U.S.A. 2016, 113,