Related Experiment Video
Updated: Feb 18, 2026

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Surface-confined [2 + 2] cycloaddition towards one-dimensional polymers featuring cyclobutadiene units.
Bay V Tran1, Tuan Anh Pham, Michael Grunst
1Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands. tvanbay@gmail.com m.a.stohr@rug.nl.
Researchers created novel 1D polymers using surface-confined [2+2] cycloaddition of pyrene. A crucial hydrogen treatment enabled byproduct removal and formation of 1,3-cyclobutadiene units for advanced molecular nanostructures.
Area of Science:
- Surface chemistry
- Materials science
- Nanotechnology
Background:
- Surface-confined synthesis enables novel molecular nanostructure construction.
- Developing new on-surface coupling reactions is key to tuning material properties.
Purpose of the Study:
- To report the formation of a 1,3-cyclobutadiene covalent C-C bonding motif.
- To investigate surface-confined [2+2] cycloaddition between pyrene moieties.
- To explore the role of hydrogen treatment in surface-confined polymerization.
Main Methods:
- Low temperature scanning tunneling microscopy (LT-STM) for structural analysis.
- X-ray photoemission spectroscopy (XPS) for chemical state determination.
- Controlled hydrogen dosing and low-temperature activation.
Main Results:
- Successful formation of 1,3-cyclobutadiene units via [2+2] cycloaddition of pyrene on a surface.
- Generation of covalent 1D polymers utilizing the 1,3-cyclobutadiene motif.
- Demonstration that hydrogen treatment is essential for byproduct removal.
Conclusions:
- The 1,3-cyclobutadiene motif can be formed through surface-confined [2+2] cycloaddition.
- Hydrogen treatment is critical for achieving high-purity polymers in this surface reaction.
- This work expands the toolkit for constructing novel molecular nanostructures via on-surface chemistry.
Related Concept Videos
Cycloaddition Reactions: Overview
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Cycloaddition Reactions: MO Requirements for Thermal Activation
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry

