TY - JOUR
T1 - A Metal-Free, Photocatalytic Method for Aerobic Alkane Iodination
AU - Hirscher, Nathanael A.
AU - Ohri, Nidhi
AU - Yang, Qiaomu
AU - Zhou, Jiawang
AU - Anna, Jessica M.
AU - Schelter, Eric J.
AU - Goldberg, Karen I.
N1 - Funding Information:
N.A.H. was supported by a postdoctoral fellowship from the Vagelos Institute for Energy Science and Technology (VIEST). E.J.S. also acknowledges the Research Corporation for Science Advancement for a Cottrell Fellowship Award in support of N.A.H. Q.Y. was supported as part of the Center for Actinide Science and Technology (CAST), an Energy Frontier Research Center (EFRC) funded by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under award number DE-SC0016568. E.J.S. also thanks the Vagelos Institute for Energy Science and Technology (VIEST) for support of this work through a Seed project. We thank Dr. Shunta Nishioka for assistance with the single-wavelength nanosecond transient absorption measurements.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/11/24
Y1 - 2021/11/24
N2 - Halogenation is an important alkane functionalization strategy, but O2 is widely considered the most desirable terminal oxidant. Here, the aerobic iodination of alkanes, including methane, was performed using catalytic [nBu4N]Cl and light irradiation (390 nm). Up to 10 turnovers of CH3I were obtained from CH4 and air, using a stop-flow microtubing system. Mechanistic studies using cyclohexane as the substrate revealed important details about the iodination reaction. Iodine (I2) serves multiple roles in the catalysis: (1) as the alkyl radical trap, (2) as a precursor for the light absorber, and (3) as a mediator of aerobic oxidation. The alkane activation is attributed to Cl• derived from photofragmentation of the electron donor-acceptor complex of I2 and Cl-. The kinetic profile of cyclohexane iodination showed that aerobic oxidation of I3- to produce I2 in CH3CN is turnover-limiting.
AB - Halogenation is an important alkane functionalization strategy, but O2 is widely considered the most desirable terminal oxidant. Here, the aerobic iodination of alkanes, including methane, was performed using catalytic [nBu4N]Cl and light irradiation (390 nm). Up to 10 turnovers of CH3I were obtained from CH4 and air, using a stop-flow microtubing system. Mechanistic studies using cyclohexane as the substrate revealed important details about the iodination reaction. Iodine (I2) serves multiple roles in the catalysis: (1) as the alkyl radical trap, (2) as a precursor for the light absorber, and (3) as a mediator of aerobic oxidation. The alkane activation is attributed to Cl• derived from photofragmentation of the electron donor-acceptor complex of I2 and Cl-. The kinetic profile of cyclohexane iodination showed that aerobic oxidation of I3- to produce I2 in CH3CN is turnover-limiting.
UR - http://www.scopus.com/inward/record.url?scp=85119923303&partnerID=8YFLogxK
U2 - 10.1021/jacs.1c08499
DO - 10.1021/jacs.1c08499
M3 - Article
C2 - 34779622
AN - SCOPUS:85119923303
SN - 0002-7863
VL - 143
SP - 19262
EP - 19267
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 46
ER -