Surface-Confined Polymerization of Halogenated Polyacenes: The Case of Dibromotetracene on Ag(110)

We studied on-surface C-C coupling of dibromotetracene on Ag(110) as a prototypical case of rodlike polyaromatic molecules functionalized with two bromine atoms on the sides.

Published in: I. Píš, et al., J. Phys. Chem. C 2016, 120, 4909-4918.

I. Píš, et al., JPCC 2016, 120, 4909-4918.
DOI: 10.1021/acs.jpcc.5b12047

On-surface synthesis of thin organic and organometallic films in a bottom-up fashion has become a promising approach for the development of new nanotechnologies. In this work we studied 5,11-dibromotetracene (C18H10Br2) as a prototypical case of rodlike polyaromatic molecules functionalized with two bromine atoms on the sides.  Upon the contact with the Ag substrate, the Br–C bonds are promptly cleaved at room temperature and Ag-coordinated protopolymers are formed along the [001] substrate direction. The organometallic dimers and trimers remain on the surface up to 523 K. The stabilization of the protopolymers is driven by the substrate anisotropy and weak interactions with nearby Br atoms. The short oligomers formed at elevated temperatures are weakly bounded to the substrate and desorb before covalent structures can be formed.The desorption temperature and the length of the coordinated polymers can be affected by surface coverage. Although organometallic dimers and trimers are the most common configurations at submonolayer coverage, longer oligomers can be achieved with a nominal coverage close to 1 ML. Nonetheless, the overall bond strength between the organic protopolymers and silver substrate is too weak to hold the protopolymers and their fragments on the surface at a temperature necessary to achieve covalent bonds between the activated DBT monomers. Additionally, the role of Br atoms is relevant for the stabilization of the organometallic species on Ag(110), differently to what observed for Cu(110).

This work was supported by the Italian MIUR through the national grant Futuro in ricerca 2012 RBFR128BEC ‘‘Beyond graphene: tailored C-layers for novel catalytic materials and green chemistry’’

Surface-Confined Polymerization of Halogenated Polyacenes: The Case of Dibromotetracene on Ag(110)
Igor Píš; Lara Ferrighi; ThanhHaiNguyen; Silvia Nappini; Luca Vaghi; Andrea Basagni; Elena Magnano; Antonio Papagni; Francesco Sedona; Cristiana Di Valentin; Stefano Agnoli; Federica Bondino

J. Phys. Chem. C, 2016, 120 (9), pp 4909–4918
DOI: 10.1021/acs.jpcc.5b12047
Publication Date (Web): February 12, 2016

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Last Updated on Wednesday, 12 December 2018 13:00