title: Photosensitized, energy transfer-mediated organometallic catalysis through electronically excited nickel(II).
abstract: Transition metal catalysis has traditionally relied on organometallic complexes that can cycle through a series of ground-state oxidation levels to achieve a series of discrete yet fundamental fragment-coupling steps. The viability of excited-state organometallic catalysis via direct photoexcitation has been demonstrated. Although the utility of triplet sensitization by energy transfer has long been known as a powerful activation mode in organic photochemistry, it is surprising to recognize that photosensitization mechanisms to access excited-state organometallic catalysts have lagged far behind. Here, we demonstrate excited-state organometallic catalysis via such an activation pathway: Energy transfer from an iridium sensitizer produces an excited-state nickel complex that couples aryl halides with carboxylic acids. Detailed mechanistic studies confirm the role of photosensitization via energy transfer.
authors.affiliation: Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Welin
authors.affiliation: Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA.
authors.forename: Chip
authors.initials: C
authors.lastname: Le
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Arias-Rotondo
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA. jkm@chemistry.msu.edu dmacmill@princeton.edu.
authors.forename: James K
authors.initials: JK
authors.lastname: McCusker
authors.affiliation: Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA. jkm@chemistry.msu.edu dmacmill@princeton.edu.
authors.forename: David W C
authors.initials: DW
authors.lastname: MacMillan