Formation par symétrie d'oligomères organométalliques chiraux à base de boroxine sur Ag(001)

International audienceTwo-dimensional molecular assemblies on surfaces have opened a way to design and control chirality, featuring promising electronic and chemical properties that depend on the local handedness of the layer. Yet, the mechanisms leading to spontaneous chiral resolution are not fully understood at every reaction stage. Here, starting from achiral 10-bromoanthracene-9-boronic acid as a molecular precursor, we demonstrate enantiomeric induction in products during the stage of covalent bonding, stemming from the competing point symmetries of the Ag(001)-supporting surface and the reaction products. Upon dehalogenation and dehydration of precursors, hexagonal boroxine rings linked by organometallic anthracene dimers are formed, which undergo a strong interaction with a fourfold symmetric substrate. The prochiral structural character of the resulting oligomer and its impact over the spatial distribution of the electronic molecular states are revealed by highresolution scanning tunneling microscopy and spectroscopy