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Updated: Jun 14, 2025
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Azobenzene-Attached (NHC)Gold(I) and (NHC)Copper(I) Complexes as Photoswitchable Catalysts
Aminul Islam Sk1, Ayan Ghosh2, Kshama Kundu3
1Department of Oils, Oleochemicals and Surfactants Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, 400019, India.
Abstract:
Photoswitchable (pre)catalysts, N,N'-bis-azobenzene-based (NHC)gold(I) and N,N'-bis-azobenzene-derived (NHC)copper(I) complexes are reported. Trans to cis isomerization of the attached photoswitchable moieties in the Au(I) complex enables four-fold decrement in the rate of oxazoline formation reaction. Whereas the progress of the copper(I) catalyzed, azide-alkyne cycloaddition reaction gets reduced by at least threefold. Alternate exposure to UV and blue light could easily toggle the rate of reactions remotely. The catalytic activity of thermodynamically stable trans-trans isomers is found to be similar to the common N-aryl substituted NHC-Au/Cu(I) complexes. NHC-Au(I) and -Cu(I) compounds bearing (trans)azobenzene moieties were characterized by X-ray diffraction. Photoswitching, recyclability studies, and the metastable isomer's thermal half-life in both complexes were studied via UV-visible spectroscopy. Whereas the extent of photoswitching and concomitant formation of geometrical isomers were investigated by using 1H-NMR spectroscopic study. Calculated percentage buried volumes of the three geometrical isomers show the trend trans-trans
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