Plasmon-Generated Solvated Electrons for Chemical Transformations

Methods for generating solvated electrons─free electrons in solution─have focused primarily on alkali metal ionization or high-energy electrons or photons. Here we report the generation of solvated electrons by exciting the plasmon resonance of Al nanocrystals suspended in solution with visible light. Two chemical reactions were performed: a radical-addition reaction with the spin-trap 2-methyl-2-nitrosopropane, and a model cyclization reaction with the radical clock 6-bromohex-1-ene. A quantum efficiency of at least ∼1.1% for plasmon absorbed photon to solvated electron generation can be inferred from the measured radical clock reaction concentration. This study demonstrates a simple way to generate solvated electrons for driving reductive organic chemical reactions in a quantifiable and controlled manner.