title: Visible-Light Actinometry and Intermittent Illumination as Convenient Tools to Study Ru(bpy)3Cl2 Mediated Photoredox Transformations.
abstract: Photoredox catalysis provides many green opportunities for radical-mediated synthetic transformations. However, the determination of the underlying mechanisms has been challenging due to lack of quantitative methods that can be easily implemented in synthetic labs, where this research tends to be centered. We report here on the development, characterization and calibration of a novel actinometer based on the photocatalyst tris(2,2'-bipyridyl)ruthenium(II) chloride (Ru(bpy)3Cl2). By using the same molecule as the photocatalyst and the actinometer, we eliminate problems associated with matching sample spectral distribution, lamp-sample spectral overlap and other problems intrinsic to doing quantitative photochemistry in a laboratory that has little expertise in this area. In order to validate our actinometer system in determining the quantum yield of a Ru(bpy)3Cl2 photosensitized reaction, we test the Ru(bpy)3Cl2 catalyzed oxidation of benzhydrol to benzophenone as a model chain reaction. We also revive the rotating sector method by updating the technique for modern LED technologies and demonstrate how intermittent illumination on the timescale of milliseconds to seconds can help probe a chain reaction, using the benzhydrol to benzophenone oxidation to validate the technique. We envision these methods to have great implications in the field of photoredox catalysis, providing researchers with valuable research tools.
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Spencer P
authors.initials: SP
authors.lastname: Pitre
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: McTiernan
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Wyatt
authors.initials: W
authors.lastname: Vine
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Rebecca
authors.initials: R
authors.lastname: DiPucchio
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Michel
authors.initials: M
authors.lastname: Grenier
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Scaiano