The mechanism of [2 + 2] cycloadditions activated by visible light and catalyzed by bis-cyclometalated Rh(iii) and Ir(iii) photocatalysts was investigated, combining density functional theory calculations and spectroscopic techniques. Experimental observations show that the Rh-based photocatalyst produces excellent yield and enantioselectivity whereas the Ir-photocatalyst yields racemates. Two different mechanistic features were found to compete with each other, namely the direct photoactivation of the catalyst-substrate complex and outer-sphere triplet energy transfer. Our integrated analysis suggests that the direct photocatalysis is the inner working of the Rh-catalyzed reaction, whereas the Ir catalyst serves as a triplet sensitizer that activates cycloadditionviaan outer-sphere triplet excited state energy transfer mechanism.

Jung, H., Hong, M., Marchini, M., Villa, M., Steinlandt, P.S., Huang, X., et al. (2021). Understanding the mechanism of direct visible-light-activated [2 + 2] cycloadditions mediated by Rh and Ir photocatalysts: combined computational and spectroscopic studies. CHEMICAL SCIENCE, 12(28), 9673-9681 [10.1039/d1sc02745j].

Understanding the mechanism of direct visible-light-activated [2 + 2] cycloadditions mediated by Rh and Ir photocatalysts: combined computational and spectroscopic studies

Marchini M.;Villa M.;Huang X.;Ceroni P.;
2021

Abstract

The mechanism of [2 + 2] cycloadditions activated by visible light and catalyzed by bis-cyclometalated Rh(iii) and Ir(iii) photocatalysts was investigated, combining density functional theory calculations and spectroscopic techniques. Experimental observations show that the Rh-based photocatalyst produces excellent yield and enantioselectivity whereas the Ir-photocatalyst yields racemates. Two different mechanistic features were found to compete with each other, namely the direct photoactivation of the catalyst-substrate complex and outer-sphere triplet energy transfer. Our integrated analysis suggests that the direct photocatalysis is the inner working of the Rh-catalyzed reaction, whereas the Ir catalyst serves as a triplet sensitizer that activates cycloadditionviaan outer-sphere triplet excited state energy transfer mechanism.
2021
Jung, H., Hong, M., Marchini, M., Villa, M., Steinlandt, P.S., Huang, X., et al. (2021). Understanding the mechanism of direct visible-light-activated [2 + 2] cycloadditions mediated by Rh and Ir photocatalysts: combined computational and spectroscopic studies. CHEMICAL SCIENCE, 12(28), 9673-9681 [10.1039/d1sc02745j].
Jung, H.; Hong, M.; Marchini, M.; Villa, M.; Steinlandt, P. S.; Huang, X.; Hemming, M.; Meggers, E.; Ceroni, P.; Park, J.; Baik, M. -H.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/849990
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