In an effort to exert more accurate control over structural features of supramolecules, we initiated this study by preparing tetratopic 2,2':6',2"-terpyridine (tpy) ligands via condensation reactions of pyrylium salts with primary amines or sodium acetate derivatives. Through self-assembly, discrete concentric hexagons were obtained instead of multiple macrocycles assembled by ditopic ligands with a 120o angle between two ligating moieties. These tetratopic ligands bearing multiple binding sites increased the total density of coordination sites and provided high geometric constraints to induce the formation of discrete structures. Assembled structures were fully characterized by NMR, ESI-MS, and traveling-wave ion mobility-mass spectrometry. These concentric hexagons were also assembled into nanobelts on highly ordered pyrolytic graphite (HOPG) surface. The synthesis based on pyrylium and pyridinium salts chemistry together with self-assembly strategy in this study will advance the design of more sophisticated 2D architectures in the future, such as high generation of concentric hexagon.

Hexagon-in-hexagon: Synthesis and self-assembly of discrete concentric hexagons

251st National Meeting (2016)

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