p-Benzosemiquinone Radical Anion on Silver Nanoparticles in Water

This communication reports the SERS observation of p-benzosemiquinone radical anion, produced on reduction of p-benzoquinone by Ag nanoparticles at the metal−water interface. The species is positively identified by comparison of the SERS spectrum with the resonance Raman spectra of the radical anion in aqueous solution. This is a rare SERS observation of a radical intermediate formed by surface reaction on nanosize silver particles in solution.