Simultaneous Harvesting of Multiple Hot Holes via Visible-Light Excitation of Plasmonic Gold Nanospheres for Selective Oxidative Bond Scission of Olefins to Carbonyls

Using visible photoexcitation of gold nanospheres we successfully demonstrate the simultaneous harvesting of plasmon-induced multiple hot holes in the complete oxidative scission of the C=C bond in styrene at room temperature to selectively form benzaldehyde and formaldehyde, which is a reaction that requires activation of multiple substrates. Our results reveal that, while extraction of hot holes becomes efficient for interband excitation, harvesting of multiple hot holes from the excited Au nanospheres becomes prevalent only beyond a threshold light intensity. We show that the alkene oxidation proceeded via a sequence of two consecutive elementary steps; namely, a binding step and a cyclic oxometallate transition state as the rate-determining step. This demonstration of plasmon-excitation-mediated harvesting of multiple hot holes without the use of an extra hole transport media opens exciting possibilities, notably for difficult catalytic transformations involving multielectron oxidation processes.

Automated summary

By using visible photoexcitation of gold nanospheres, we have successfully collected multiple plasmon-induced "hot holes" to completely oxidatively cleave the C=C bond in styrene at room temperature, selectively forming benzaldehyde and formaldehyde, which is a reaction requiring activation of multiple substrates. Our findings indicate that efficient extraction of hot holes occurs with interband excitation, while harvesting of multiple hot holes from excited Au nanospheres becomes predominant only beyond a threshold light intensity. We demonstrate that alkene oxidation proceeds through a sequence of two consecutive elementary steps, namely a binding step and a cyclic oxometallate transition state as the rate-determining step. This plasmon excitation-mediated harvesting of multiple hot holes without the need for an extra hole transport media opens up exciting possibilities for difficult catalytic transformations involving multielectron oxidation processes.