On-Surface Activation of Chemical Reactions for Functional Interfaces

On-Surface Molecular Sciences inspired the fabrication of a large variety of atomically precise nanostructures and allowed the production of low-dimensional materials with outstanding electronic properties. Numerous surface-supported nanostructures are constantly developed. They are cheap to produce and display highly tunable performances. Their possible applications encompass diverse areas of research such as catalysis, organic electronics, surface functionalization and nanopatterning[1].

The key aspect towards innovative bottom-up fabrication protocols is the on-surface activation of chemical reaction and the covalent stabilization of complex molecular architectures[2]. Commonly, this is obtained by using suitable reactants and, in a second stage, by activating the covalent networking between the molecular precursors via thermal[3], photochemical[4] or scanning-probe tip induced[5] reactions. Photochemistry, in particular, was furthered as a promising approach for this purpose and pioneering examples[6] allowed a deeper understanding of light-induced on-surface chemical reactions. In this context, the Scanning Tunneling Microscopy and Spectroscopy (STM/STS) and other X-ray surface analysis techniques (XPS and NEXAFS, among the others) provide the necessary resolution for this studies at various interfaces.

In this talk, I will introduce various techniques that allow the activation of precise on-surface chemical reactions. It will be shown how the recombination of the starting materials and the detection of the reaction products is strongly affected by the environment in which the reaction takes place. A comparison between the molecular behavior on metallic and non-metallic surfaces will also be proposed. Finally, it will be shown how the rational molecular design and the manipulation of the molecular precursors i.e. by in-situ chemical transformations and by STM-tip functionalization, allow to tailor and detect exceptional molecular properties.

[1] K. Mali et al., Chem. Soc. Rev., 2017,46, 2520-2542
[2] P. Held et al., Chem. Eur. J., 2017, 23, 5874-5892
[3] A. Basagni et al., J. Am. Chem. Soc., 2015, 137, 1802–1808
[4] L. Colazzo et al., J. Am. Chem. Soc., 2016, 138 , 10151–10156
[5] L. Colazzo et. al., Chem. Comm., 2018, (10.1039/c8cc04402c)
[6] A. Basagni et. al., Chem. Eur. J., 2014, 20, 14296-14304