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Efficient Photochemical Dihydrogen Generation Initiated by a Bimetallic Self-Quenching Mechanism
journal contribution
posted on 2016-09-27, 00:00 authored by Matthew
B. Chambers, Daniel A. Kurtz, Catherine L. Pitman, M. Kyle Brennaman, Alexander J. M. MillerArtificial
photosynthesis relies on coupling light absorption with
chemical fuel generation. A mechanistic study of visible light-driven
H2 production from [Cp*Ir(bpy)H]+ (1) has revealed a new, highly efficient pathway for integrating light
absorption with bond formation. The net reaction of 1 with a proton source produces H2, but the rate of excited
state quenching is surprisingly acid-independent and displays no observable
deuterium kinetic isotopic effect. Time-resolved photoluminescence
and labeling studies are consistent with diffusion-limited bimetallic
self-quenching by electron transfer. Accordingly, the quantum yield
of H2 release nearly reaches unity as the concentration
of 1 increases. This unique pathway for photochemical
H2 generation provides insight into transformations catalyzed
by 1.
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Efficient Photochemical Dihydrogen Generation Initiatedacid-independentinsightquantumchemical fuel generationH 2 generationsourcelight absorptionH 2 releaseconcentrationlight-driven H 2 productionBimetallic Self-Quenching MechanismtransferpathwayunityformationprotonphotoluminescenceTime-resolvedtransformationdeuteriumelectrondisplaydiffusion-limited bimetallic self-quenchingCpphotosynthesisbond