| AVS 64th International Symposium & Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS+HC-TuM |
| Session: | Controlling Mechanisms of Surface Chemical Reactions |
| Presenter: | Junfa Zhu, University of Science and Technology of China |
| Authors: | Q.T. Fan, University of Science and Technology of China T. Wang, University of Science and Technology of China J.F. Zhu, University of Science and Technology of China |
| Correspondent: | Click to Email |
The bottom-up construction of low-dimensional macromolecular nanostructures directly on a surface is a promising approach for future application in molecular electronics and integrated circuit production. However, challenges still remain in how to control the reaction pathways toward the formation of targeted nanostructures or dimensions. In this presentation, I will report our recent studies on the on-surface synthesis of low dimensional organic nanostructures on different substrate surfaces. These studies were performed under ultra-high vacuum (UHV) conditions using a combination of scanning tunnelling microscopy (STM), low energy electron diffraction (LEED) and high-resolution X-ray photoelectron spectroscopy (HR-XPS). Several examples will be shown to demonstrate that by employing different substrate templates,1-4 special high-dilution synthesis condition5 or hydrogen bond protection with dedicated precursor molecules on surfaces6, surface reactions can be driven with different pathways towards the desired products. For example, on Cu(111) and Cu(110), after depositing the same precursor molecule, 4,4’’-dibromo-meta-terphenyl (DMTP), at elevated temperatures, Ullmann coupling reaction can proceed via different pathways to form different nanostructures.1-3 While on the Cu(110)-(2x1)O surface, by controlling the width of the Cu stripes, the spatial confinement effect can steer the reaction of DMTP to form either 1D zigzag organometallic oligomeric chains with different lengths or organometallic macrocycles with different widths.4 More interestingly, when recently we transplanted the (pseudo-) high dilution method in solution to the conditions of on-surface synthesis in UHV, we found that the reaction of DMTP on Ag(111) can be tailored to specially form cyclic hyperbenzene with high-yield (84%) in contrast to the commonly formed zig-zag open-chain polymers.5 Except for the presentation of these different structures on surfaces, we will also discuss the principles and mechanisms behind.
This work is supported by the National Natural Science Foundation of China (21473178) and the National Basic Research Program of China (2013CB834605)
References:
(1) Fan, Q.; Wang, C.; et al., Angew. Chem. Int. Ed.2013, 52, 4668.
(2) Fan, Q.; Wang, C.; et al., ACS Nano2014, 8, 709.
(3) Dai, J.; Fan, Q.; et al., Phys. Chem. Chem. Phys.2016, 18, 20627.
(4) Fan, Q.; Dai, J.; et al., ACS Nano2016, 10, 3747.
(5) Fan, Q.; Wang, T.; et al., ACS Nano2017, DOI: 10.1021/acsnano.7b01870.
(6) Wang, T.; Lv, H.; et al., Angew. Chem. Int. Ed. 2017, 56, 4762.