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Efficient electron transfer across hydrogen bond interfaces by proton-coupled and -uncoupled pathways.

ABSTRACT: Thermal electron transfer through hydrogen bonds remains largely unexplored. Here we report the study of electron transfer through amide-amide hydrogen bonded interfaces in mixed-valence complexes with covalently bonded Mo2 units as the electron donor and acceptor. The rate constants for electron transfer through the dual hydrogen bonds across a distance of 12.5?Å are on the order of ? 1010?s-1, as determined by optical analysis based on Marcus-Hush theory and simulation of ?(NH) vibrational band broadening, with the electron transfer efficiencies comparable to that of ? conjugated bridges. This work demonstrates that electron transfer across a hydrogen bond may proceed via the known proton-coupled pathway, as well as an overlooked proton-uncoupled pathway that does not involve proton transfer. A mechanistic switch between the two pathways can be achieved by manipulation of the strengths of electronic coupling and hydrogen bonding. The knowledge of the non-proton coupled pathway has shed light on charge and energy transport in biological systems.

SUBMITTER: Cheng T

PROVIDER: S-EPMC6449364 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature

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