TY - JOUR
T1 - Mechanistic Analysis of Metallaphotoredox C-N Coupling
T2 - Photocatalysis Initiates and Perpetuates Ni(I)/Ni(III) Coupling Activity
AU - Till, Nicholas A.
AU - Tian, Lei
AU - Dong, Zhe
AU - Scholes, Gregory D.
AU - MacMillan, David W.C.
N1 - Funding Information:
This work was supported as part of BioLEC, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science under Award # DE-SC0019370 and kind gifts from Merck, BMS, Pfizer, Janssen, Genentech, and Eli Lilly. We acknowledge the Princeton Catalysis Initiative for supporting this work. N.A.T. and L.T. acknowledge Princeton University, E. Taylor, and the Taylor family for an Edward C. Taylor Fellowship. We thank Phil Jeffrey of Princeton University for X-ray crystallographic structure determination. We thank Megan H. Shaw and Emily B. Corcoran for their help in carrying out initial studies.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/9/16
Y1 - 2020/9/16
N2 - 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.
AB - 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.
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U2 - 10.1021/jacs.0c05901
DO - 10.1021/jacs.0c05901
M3 - Article
C2 - 32786779
AN - SCOPUS:85091127070
SN - 0002-7863
VL - 142
SP - 15830
EP - 15841
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 37
ER -