Proton-NMR study on chemisorption of ethylene on platinum powder

The high-temperature phase of ethylene on surfaces of Pt powder has been studied by proton-NMR in order to decide whether the surface species is the ethylidyne species (CH₃C) proposed by Kesmodel et al. or the multiple-bonded species (CH₂CH) proposed by Demuth. The observed NMR spectrum is not attributable to CH₃-groups on the surfaes, but can be interpreted as the superposition of two signals, one originating from CH₂-groups and the other from CH-groups. In other words, the results suggest that the surface species is the multiple-bonded species.