Work

Mechanistic Analysis of Metallaphotoredox C–N Coupling: Photocatalysis Initiates and Perpetuates Ni(I)/Ni(III) Coupling Activity

Year: 2020

Type: article

Abstract: The combined use of reaction kinetic analysis, ultrafast spectroscopy, and stoichiometric organometallic studies has enabled the elucidation of the mechanistic underpinnings to a photocatalytic C-N cross-coupling reaction. Steady-state and ultrafast spectroscopic techniques were used to track the excited-state evolution of the employed iridium photocatalyst, determine the resting states of both iridium and nickel catalysts, and uncover the photochemical mechanism for reductive activation of the nickel cocatalyst. Stoichiometric organometallic studies along with a comprehensive kinetic study of the reaction, including rate-driving force analysis, unveiled the crucial role of photocatalysis in both initiating and sustaining a Ni(I)/Ni(III) cross-coupling mechanism. The insights gleaned from this study further enabled the discovery of a new photocatalyst providing a >30-fold rate increase.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.0c05901

Authors: Nicholas A. Till, Lei Tian, Zhe Dong, Gregory D. Scholes, David W. C. MacMillan

Institution: Princeton University

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green