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Controlled Photocatalytic Hydrocarbon Oxidation by Uranyl Complexes
Author(s) -
Arnold Polly L.,
Purkis Jamie M.,
Rutkauskaite Ryte,
Kovacs Daniel,
Love Jason B.,
Austin Jonathan
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201900037
Subject(s) - uranyl , photocatalysis , chemistry , bond cleavage , catalysis , photochemistry , uranyl nitrate , uranium , inorganic chemistry , hydrocarbon , ligand (biochemistry) , organic chemistry , ion , materials science , biochemistry , receptor , metallurgy
Controlled, photocatalytic C−H bond activations are key reactions in the toolkits of the modern synthetic chemist. While it is known that the uranyl(VI) ion, [U VI O 2 ] 2+ , the environmentally dominant form of uranium, is photoactive, most literature examines its luminescent properties, neglecting its potential synthetic utility for photocatalytic C−H bond cleavage. Here, we synthesise and fully characterise an air‐stable and hydrocarbon‐soluble uranyl phenanthroline complex, [U VI O 2 (NO 3 ) 2 (Ph 2 phen)], U Ph2phen , and demonstrate that it can catalytically abstract hydrogen atoms from a variety of organic substrates under visible light irradiation. We show that the commercially available parent complex, uranyl nitrate ([U VI O 2 (NO 3 ) 2 (OH 2 ) 2 ]⋅4H 2 O; U NO3 ), is also competent, but from electronic spectroscopy we attribute the higher rates and selectivity of U Ph2phen to ligand‐mediated electronic effects. Ketones are selectively formed over other oxygenated products (alcohols, etc .), and the catalytic oxidation of substrates containing a benzylic C−H position is particularly improved for U Ph2phen . We also show uranyl‐mediated photocatalytic C−C bond cleavage in a model lignin compound for the first time.