Self‐Assembly of Nanographenes

• Published in: Angewandte Chemie International Edition Vol. 60; no. 23; pp. 12706 - 12711
• Main Authors: Matsumoto, Ikuya, Sekiya, Ryo, Haino, Takeharu
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.06.2021
• Edition: International ed. in English
• Subjects: Aggregates; Assembly; graphene; graphene quantum dots; Low concentrations; Mica; Molecular modelling; Morphology; nanographene; Optical measurement; Organic solvents; Polarity; Polymers; self-assembly; Size distribution; Solvents; Sonication; supramolecular chemistry; self-assembly; nanographene; graphene quantum dots; supramolecular chemistry; graphene
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202101992

Suitably decorated small aromatic systems can organize stacked structures that display interesting properties arising from their unique morphologies. Although nanographenes produced by top‐down methods have graphitic domains and can in principle be applied for such supramolecular systems, to our knowledge, no such example has been reported thus far. This is partly because of their limited solubility in organic solvents and partly because of their wide lateral size distribution. To realize nanographene‐based supramolecular aggregates, nanographenes carrying alkyl chains with narrow lateral size distributions are employed. We find that the nanographenes undergo self‐assembly and that self‐assembly is regulated by concentration, solvent polarity, temperature, and sonication. Optical measurements and AFM images indicate that stacked structures are possible candidates for aggregates. A molecular mechanics calculation models the interactions in the aggregates. The nanographenes showed concentration‐dependent morphologies on mica, stacked structures at low concentrations and polymer‐like network structures on mica at higher concentrations. Suitably decorated small aromatic systems can organize one‐dimensionally stacked structures. We found that nanographenes carrying long alkyl chains behaved similarly. The experiments demonstrated that the nanographenes underwent aggregation and disaggregation regulated by concentration, solvent polarity, temperature, and sonication.