We investigate the surface-catalyzed dissociation of the archetypal molecular
switch azobenzene on the Cu(111) surface. Based on X-ray photoelectron
spectroscopy, normal incidence X-ray standing waves and density functional
theory calculations a detailed picture of the coverage-induced formation of
phenyl nitrene from azobenzene is presented. Furthermore, a comparison to the
azobenzene/Ag(111) interface provides insight into the driving force behind
the dissociation on Cu(111). The quantitative decay of azobenzene paves the
way for the creation of a defect free, covalently bonded monolayer. Our work
suggests a route of surface functionalization via suitable azobenzene
derivatives and the on surface synthesis concept, allowing for the creation of
complex immobilized molecular systems
