Hexakis(4-iodophenyl)-peri-hexabenzocoronene - A Versatile Building Block for Highly Ordered Discotic Liquid Crystalline Materials

Jishan Wu, Mark D. Watson, Li Zhang, Zhaohui Wang, Klaus Müllen

Research output: Contribution to journalArticlepeer-review

197 Scopus citations

Abstract

Hexakis (4-iodophenyl)-peri-hexabenzocoronene (5), a novel functionalizable mesogenic building block, was prepared by rational multistep synthesis. Although sparingly soluble in common solvents, it can be obtained in pure form and then functionalized via Hagihara-Sonogashira coupling to give a series of highly ordered columnar liquid crystalline molecules 14a-c. The total synthesis involves five 6-fold transformations, all in excellent to near quantitative isolated yields. Their thermotropic liquid crystalline behavior was studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide-angle X-ray diffraction (WAXD). Compared to the normal alkyl-subsituted hexabenzocoronenes (HBCs), 14a-c exhibit more highly ordered columnar mesophases, including three-dimensionally ordered super-structures (helical columnar mesophase). These could arise from additional intracolumnar π-π interactions between, and space-filling requirements introduced by, the rigid-rod side groups. Atomic force microscopy (AFM) revealed self-assembled bundles of columnar aggregates in spin-coated films and isolated several-micron-long nanoribbons composed of a defined number of columns in drop cast films.

Original languageEnglish
Pages (from-to)177-186
Number of pages10
JournalJournal of the American Chemical Society
Volume126
Issue number1
StatePublished - Jan 14 2004

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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