Supramolecular Scaffold for Tailoring the Two-Dimensional Assembly of Functional Molecular Units into Organic Thin Films

Franco King Chi Leung, Fumitaka Ishiwari, Takashi Kajitani, Yoshiaki Shoji, Takaaki Hikima, Masaki Takata, Akinori Saeki, Shu Seki, Yoichi M.A. Yamada, Takanori Fukushima

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

Tailoring structurally anisotropic molecular assemblies while controlling their orientation on solid substrates is an important subject for advanced technologies that use organic thin films. Here we report a supramolecular scaffold based on tripodal triptycene assemblies, which enables functional molecular units to assemble into a highly oriented, multilayered two-dimensional (2D) structure on solid substrates. The triptycene building block carries an ethynyl group and three flexible side chains at the 10- and 1,8,13-positions, respectively. These bridgehead-substituted tripodal triptycenes self-assembled on solid substrates to form a well-defined "2D hexagonal + 1D lamellar" structure, which developed parallel to the surface of the substrates. Remarkably, the assembling properties of the triptycene building blocks, particularly for a derivative with tri(oxyethylene)-containing side chains, were not impaired when the alkyne terminal was functionalized with a large molecular unit such as C60, which is comparable in diameter to the triptycene framework. Consequently, thin films with a multilayered 2D assembly of the C60 unit were obtained. Flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurements revealed that the C60 film exhibits highly anisotropic charge-transport properties. Bridgehead-substituted tripodal triptycenes may provide a versatile supramolecular scaffold for tailoring the 2D assembly of molecular units into a highly oriented thin film, and in turn for exploiting the full potential of anisotropic molecular functions.

Original languageEnglish
Pages (from-to)11727-11733
Number of pages7
JournalJournal of the American Chemical Society
Volume138
Issue number36
DOIs
Publication statusPublished - 2016 Sep 14

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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