Combined XPS and DFT investigation of the adsorption modes of methyl enol ether functionalized cyclooctyne on Si(001)

The reaction of methyl enol ether functionalized cyclooctyne on the silicon (001) surface was investigated by means of X‐ray photoelectron spectroscopy (XPS) and density functional theory (DFT). Three different groups of final states were identified; all of them bind on Si(001) via the strained triple bond of cyclooctyne but they differ in the configuration of the methyl enol ether group. The majority of molecules adsorbs without additional reaction of the enol ether group; the relative contribution of this configuration to the total coverage depends on substrate temperature and coverage. Further configurations include enol ether groups which reacted on the silicon surface either via ether cleavage or enol ether groups which transformed on the surface into a carbonyl group. Binding via strained bond: Methyl enol ether functionalized cylooctyne is shown to adsorb on Si(001) preferentially via the strained triple bond of cyclooctyne. It can thus serve as an interface between the silicon surface and organic architectures which are coupled via the intact enol ether group. Side reactions include ether cleavage and the formation of an aldehyde group as observed by XPS and DFT.