title: A Luminescent Zirconium(IV) Complex as a Molecular Photosensitizer for Visible Light Photoredox Catalysis.
abstract: Titanium and zirconium complexes carrying two 2,6-bis(pyrrolyl)pyridine ligands have been synthesized and characterized. The neutral complexes Ti(MePDP)2and Zr(MePDP)2(MePDP = 2,6-bis(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine) show intense ligand-to-metal charge-transfer bands in the visible region and undergo multiple reversible redox events under highly reducing conditions. Zr(MePDP)2exhibits photoluminescent behavior and its excited state can be quenched by mild reductants to generate a powerful electron transfer reagent with a ground state potential of -2.16 V vs Fc+/0. This reactivity was utilized to facilitate dehalogenation reactions, the reduction of electron-poor olefins, and the reductive coupling of benzyl bromide via photoredox catalysis. In these reactions, the earth-abundant metal complex Zr(MePDP)2acts as a substitute for the precious metal photosensitizer [Ru(bpy)3]2+.
authors.affiliation: C. Eugene Bennett Department of Chemistry, West Virginia University , 100 Prospect Street, Morgantown, West Virginia 26506, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: C. Eugene Bennett Department of Chemistry, West Virginia University , 100 Prospect Street, Morgantown, West Virginia 26506, United States.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Petersen
authors.affiliation: C. Eugene Bennett Department of Chemistry, West Virginia University , 100 Prospect Street, Morgantown, West Virginia 26506, United States.
authors.forename: Carsten
authors.initials: C
authors.lastname: Milsmann