Volume 43, Issue 2 pp. 161-168
Concise Report

A Cascade Reaction Triggered by H-H Steric Hindrance: Dimeric Covalent Organic Frameworks on Au(111) and Dimeric Nanoribbons on Ag(111)

Boyu Fu

Boyu Fu

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

These authors made equal contribution.

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Jianchen Lu

Corresponding Author

Jianchen Lu

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

These authors made equal contribution.

E-mail: [email protected], [email protected], [email protected]Search for more papers by this author
Jianqun Geng

Jianqun Geng

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

These authors made equal contribution.

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Yong Zhang

Yong Zhang

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

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Wei Xiong

Wei Xiong

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

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Gefei Niu

Gefei Niu

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

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Yi Zhang

Yi Zhang

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

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Lei Gao

Corresponding Author

Lei Gao

Faculty of Science, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming, Yunnan, 650500 China

E-mail: [email protected], [email protected], [email protected]Search for more papers by this author
Jinming Cai

Corresponding Author

Jinming Cai

Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming, Yunnan, 650093 China

Southwest United Graduate School, Kunming, Yunnan, 650093 China

E-mail: [email protected], [email protected], [email protected]Search for more papers by this author
First published: 07 October 2024
Citations: 4

Comprehensive Summary

In on-surface synthesis, dimers are typically utilized to explore reaction mechanisms or as intermediates in the formation of final products. However, constructing the innovative nanostructures with dimers as building blocks remains challenging. Here, using non-planar 2,2′,7,7′-tetrabromo-9,9′-biflurenyliden molecules, we have successfully synthesized dimeric covalent organic frameworks (COFs) on the Au(111) surface through a temperature-controlled cascade reaction. Notably, the H-H steric hindrance within precursors caused by double bonds leads to selective stepwise debromination during the thermal annealing, which promotes the dimerization through intermolecular Ullmann coupling and cyclodehydrogenation reaction to form COFs primarily constituted by dimer building blocks. Combining scanning tunneling microscopy/spectroscopy and density functional theory calculations, we have precisely confirmed the structural evolution and reaction mechanism. Furthermore, by introducing Ag adatoms to form C−Ag−C intermediates, we have successfully regulated the reaction path and synthesized one-dimensional nanoribbons with dimers as building blocks. This work not only validates the strategy of synthesizing dimeric nanostructures on different surfaces through cascade reactions induced by precursor design, but also enriches the research field of surface synthesis of COFs and nanoribbons.

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