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O: Fachverband Oberflächenphysik
O 37: Nanostructures at Surfaces III
O 37.6: Talk
Tuesday, March 8, 2016, 15:30–15:45, S054
On-Surface Reductive Coupling of Aldehydes on Au(111) — •Oscar Díaz Arado1,2, Harry Mönig1,2, Jörn-Holger Franke3, Alexander Timmer1,2, Philipp Held4, Armido Studer4, and Harald Fuchs1,2 — 1Physikalisches Institut, Westfälische Wilhelms-Universität, Münster, Deutschland — 2Center for Nanotechnology (CeNTech), Münster, Deutschland — 3Department of Physics, Université Libre de Bruxelles, Bruxelles, Belgium — 4Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Deutschland
The on-surface covalent coupling of organic molecules has been shown to have great potential as a promising approach for the bottom-up design of novel functional organic nanomaterials. Herein we report the C-C coupling of a terephthaldehyde to produce polyphenylene vinylene oligomers on a Au(111) surface. Scanning tunneling microscopy and photoelectron spectroscopy experiments revealed the success of the covalent coupling after oxygen dissociation and subsequent desorption from the surface. These results, together with density functional theory calculations, showed that the typical diolate-mediated reaction mechanism for the reductive coupling of carbonyls does not apply in this case. Instead, the reaction proceeds after C-H activation of the aldehyde moiety followed by a two-step deoxygenation process involving reactive sites on the substrate. With this on-surface synthesis approach, nanostructures with tunable optoelectronic properties on substrates can be developed, thus increasing the existing pool of suitable reactions for the growth of organic nanostructures on surfaces.