On-Surface Driven Formal Michael AdditionProduces m-PolyanilineOligomers on Pt (111)

[EN] On-surface synthesis is emerging as a highly rational bottom-up methodology for the synthesis of molecular structures that are unattainable or complex to obtain by wet chemistry. Here, oligomers of meta-polyaniline, a known ferromagnetic polymer, were synthesized from para-aminophenol building-blocks via an unexpected and highly specific on-surface formal 1, 4 Michael-type addition at the meta position, driven by the reduction of the aminophenol molecule. We rationalize this dehydrogenation and coupling reaction mechanism with a combination of in situ scanning tunneling and non-contact atomic force microscopies, high-resolution synchrotron-based X-ray photoemission spectroscopy and first-principles calculations. This study demonstrates the capability of surfaces to selectively modify local molecular conditions to redirect well-established synthetic routes, such as Michael coupling, towards the rational synthesis of new covalent nanostructures.
Spanish MINECO(MAT2017-85089-C2-1-R, RYC-2015–17730), European Research Council (ERC) under contract (ERC-2013-SYG-610256 NANOCOSMOS), Comunidad de Madrid via Programa de InvestigaciónTecnologías 2018 (FOTOART-CMS2018/NMT-4367), and the innovation program under grantagreements 785219 and 881603 (GrapheneCore2 and Gra-pheneCore3-Graphene-based disruptive technologies,re-spectively). CSS acknowledges MCIU for the “RamnyCajal” contract (RYC2018-024364-I). NRdA is grateful tothe Spanish MINECO for support from the FPI program(BES-2015–072642)