Efficient Photochemical Dihydrogen Generation Initiated by a Bimetallic Self-Quenching Mechanism
journal contributionposted on 2016-09-27, 00:00 authored by Matthew B. Chambers, Daniel A. Kurtz, Catherine L. Pitman, M. Kyle Brennaman, Alexander J. M. Miller
Artificial 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.
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