Radical-Mediated C-C Coupling of Alcohols Induced by PlasmonicHot Carriers

Abstract

The C-C coupling reactions of aliphatic alcohols to aromatics and larger-mass compounds have large endothermicities and activation energies, calling for catalystsoperating at high temperatures. Here, we demonstrate that plasmon-excited nanoparticlescatalyze the C-C coupling of aliphatic alcohols at room temperature to producepolyaromatic hydrocarbons and graphene oxide. The conversion is quenched by radical andelectron scavengers and by the surface passivation of metals, suggesting that the reactionproceeds through alkoxy, peroxyl, hydroxyalkyl, and alkyl radical intermediates created bythe metal to molecule transfer of plasmonic hot carriers. Besides being thefirst realization ofC-C coupling of aliphatic alcohols at room temperature, the result constitutes a rareexample of an endothermic plasmon-induced reaction producing new bonds and a newmethod for photogenerating graphene derivatives. More importantly, the resultdemonstrates the facile generation of organic radicals directly from alcohols, which maybe used as precursors for radical-based organic reactions.