Carbon-carbon bond activation in adsorbed cyclopropane by gas-phase atomichydrogen on the Ni(111) surface

Gas-phase atomic hydrogen induces C-C bond activation in adsorbed cycloprop ane on the Ni(lll) surface, while coadsorbed hydrogen does not. Propane is the only desorbing product observed during subsequent temperature-programme d desorption experiments. Three propane formation pathways are observed. Ga sphase atomic hydrogen reacts with adsorbed cyclopropane to form intermedia tes at 105 K, which are hydrogenated by coadsorbed hydrogen to form propane at 116 and 210 K. The 116 K pathway is similar to previous results obtaine d on the Ni(100) surface where propyl was determined to be the primary inte rmediate. The 210 K pathway has no analogue on the Ni(100) surface and is t hought to involve a more stable form of propyl on the Ni(111) surface. The reaction of subsurface hydrogen with adsorbed cyclopropane leads to propane formation at 170 K on the Ni(111) surface. The absence of methane and etha ne formation indicates that no multiple C-C bond activation processes occur . In contrast, cyclopropane desorption occurs before sufficient thermal ene rgy is available to induce C-C bond breaking with coadsorbed hydrogen.