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Molecular clusters in two-dimensional surface-confined nanoporous molecular networks: structure, rigidity, and
Shengbin Lei1, Kazukuni Tahara, Xinliang Feng
1Department of Chemistry, Division of Molecular and Nanomaterials, Laboratory of Photochemistry and Spectroscopy, and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, B-3001 Leuven, Belgium.
Journal of the American Chemical Society
|May 10, 2008
Summary
Hexadehydrotribenzo[12]annulene (DBA) derivatives self-assemble into porous or dense patterns. Nanographene guests can be incorporated, forming new porous structures and demonstrating dynamic host-guest interactions.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Surface Science
Background:
- Hexadehydrotribenzo[12]annulene (DBA) derivatives are macrocyclic compounds capable of self-assembly.
- The arrangement of these molecules is influenced by the length of their alkoxy chains.
- Understanding self-assembly at the liquid/solid interface is crucial for designing functional materials.
Purpose of the Study:
- To investigate the self-assembly behavior of DBA derivatives with varying alkoxy chain lengths.
- To explore the interactions between DBA derivatives and nanographene guests.
- To understand the structural transformations induced by guest molecules.
Main Methods:
- Scanning tunneling microscopy (STM) was employed to visualize self-assembly at the liquid/solid interface.
- Experiments were conducted in both the absence and presence of nanographene guests.
- Varying lengths of alkoxy chains on DBA derivatives were systematically studied.
Main Results:
- DBA derivatives with short alkoxy chains formed 2D porous honeycomb patterns.
- DBA derivatives with long alkoxy chains formed dense-packed linear patterns.
- Nanographene guests were incorporated into existing porous patterns or induced the formation of new porous structures from dense patterns, with pore sizes up to 5.4 nm.
- Up to six nanographene molecules could be hosted in cavities of DBA derivatives with OC20H41 chains.
- The host matrix exhibited flexibility, adapting its structure to accommodate guest molecules due to weak intermolecular interactions.
Conclusions:
- The self-assembly of DBA derivatives is tunable by alkoxy chain length, leading to distinct 2D patterns.
- Nanographene guests can template the formation of porous structures and are actively incorporated into DBA matrices.
- The observed dynamic processes highlight the adaptability of these supramolecular systems for host-guest chemistry.
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