Site selective conversion of self-assembled molecular films into reactive functional groups has attracted considerable interest, as the resultant materials can be widely applied to areas including bio chips, diagnostic nanoarrays, and molecular assembly patterning.1 Regarding studies to form reactive functionalities by the functional group modifications on self-assembled thin films, the following approaches have been reported: nitroaldimine reduction and amine formation by soft X-rays or electronic beams, 2,3 thiol formation by electric reduction of thiocarbamate, 4 alkane oxide formation by oxidative photolysis of alkane, 5 photochemical crosslinking of biphenyl thiol, 6 triazole formation, 7 and photon or electron mediated alkyne formation from the furoxan. 8,9With respect to patterning of molecular layers on a material surface, photochemical conversion is considered as one of the best techniques to obtain arrayed functionalities on a solid surface. For the photochemical generation of functional groups on self-assembled monolayers (SAMs), especially in a patterned manner, the selection of photosensitive molecules consisting of SAMs is considered essential. The molecules should maintain stable molecular assembly states, and should also be sensitive to light-irradiation in order to afford new functional groups that can initiate subsequent functional modifications for adequate surface patterning.Furoxan (furazan N-oxide) compounds are known to be the only potential alkyne precursor that can generate triple bonds on solid phases by photochemical conversions.8-11 In our previous studies regarding the alkyne formation from furoxans on silica, however, imine bonding between furoxanaldehyde and an amino group on the silica surface limited its wide application because of air-instability-induced decomposition and a reductive response with the irradiating light. 2,9Thus, furoxanethiols PFT and BPFT were deposited on gold surfaces and then exposed to EUV (Extreme Ultra Visible) in order to fabricate stable furoxan thin-film via simpler methods and examine the photo-reactivity of furoxan derivatives. Since amino linkers were not used in the process for making furoxan thin films on gold surface, XPS analysis of nitrogen atoms could be processed more clearly. We observed that the furoxanthiols showed different adsorption properties on the gold surface and different response upon EUV irradiation generating dinitrosoalkene and furazan functional groups together with alkyne on the gold surface (Scheme 1), in contrast with results obtained on silica.Furoxan compounds PFT and BPFT were vapor deposited on gold and the resulting thin films were irradiated by EUV. HRPES (High Resolution Photoemission Spectroscopy) data for furoxans on gold surfaces before and after irradiation are presented in Figure 2. Shown are surfacesensitive N 1s core level spectra of the furoxans thin film after taken with photon energy of 470 eV. The dots are measured spectra and the solid curves are fitting results. The N 1s spectrum was fitted with two comp...

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