Steering Self‐Assembly of Three‐Dimensional Iptycenes on Au(111) by Tuning Molecule‐Surface Interactions

• Published in: Angewandte Chemie International Edition 2022-06, Vol.61 (25), p.e202201044-n/a
• Main Authors: Grossmann, Lukas, Ringel, Eva, Rastgoo‐Lahrood, Atena, King, Benjamin T., Rosen, Johanna, Heckl, Wolfgang M., Opris, Dorina, Björk, Jonas, Lackinger, Markus
• Format: Article
• Language: English
• Subjects: Adsorption; Anthracene; Assembly; Crystal Engineering; Density functional theory; Fine structure; Iodine; Scanning Tunneling Microscopy; Self-Assembly; Steering; Surface chemistry; Surface-Passivation; Triptycene; Ultrastructure
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202201044

Self‐assembly of three‐dimensional molecules is scarcely studied on surfaces. Their modes of adsorption can exhibit far greater variability compared to (nearly) planar molecules that adsorb mostly flat on surfaces. This additional degree of freedom can have decisive consequences for the expression of intermolecular binding motifs, hence the formation of supramolecular structures. The determining molecule‐surface interactions can be widely tuned, thereby providing a new powerful lever for crystal engineering in two dimensions. Here, we study the self‐assembly of triptycene derivatives with anthracene blades on Au(111) by Scanning Tunneling Microscopy, Near Edge X‐ray Absorption Fine Structure and Density Functional Theory. The impact of molecule‐surface interactions was experimentally tested by comparing pristine with iodine‐passivated Au(111) surfaces. Thereby, we observed a fundamental change of the adsorption mode that triggered self‐assembly of an entirely different structure. Passivation of Au(111) with an iodine monolayer provides effective means to steer the adsorption of three‐dimensional (f)antrip molecules. The stronger interaction on pristine Au(111) favours adsorption with two anthracene blades flat, promoting self‐assembly of a densely packed structure. By contrast, on passivated Au(111) f(antrip) adsorbs with its three anthracene blades edge‐on, giving rise to self‐assembly of a porous structure.