Pentagon‐Embedded Cycloarylenes with Cylindrical Shapes

• Published in: Angewandte Chemie International Edition Vol. 56; no. 31; pp. 9106 - 9110
• Main Authors: Hitosugi, Shunpei, Sato, Sota, Matsuno, Taisuke, Koretsune, Takashi, Arita, Ryotaro, Isobe, Hiroyuki
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 24.07.2017
• Edition: International ed. in English
• Subjects: Absorption spectroscopy; Arrays; Carbon; Carbon nanotubes; Chemical synthesis; Conjugation; Crystal structure; Cylinders; Embedded systems; Hexagons; Information systems; macrocycles; nanostructures; Nanotechnology; Nanotubes; NMR; Nuclear magnetic resonance; pentagons; Single crystals; Spectroscopic analysis; Spectroscopy; Stereoisomerism; Structural analysis; X-ray diffraction; nanotubes; macrocycles; conjugation; nanostructures; pentagons
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201704676

Cylinder‐shaped graphitic networks in carbon nanotubes have attracted interest from scientists in various disciplines. The chemical synthesis of segments thereof is considered as a challenging and appealing subject in chemistry, and deepens our understanding of curved and conjugated arrays of hexagons. We herein report the synthesis of cylinder‐shaped molecules containing non‐hexagon bridges in their conjugated systems. Multiple pentagon units were embedded in the cylinder‐shaped discrete molecules, and the stereoisomerism originating from their helical carbon arrangements was studied. Structural analysis by NMR, UV/Vis absorption spectroscopy, and single‐crystal X‐ray diffraction provided fundamental experimental information on the curved systems with conjugation across the pentagons. This study provides the first experimental guide for further explorations of anomalous non‐hexagon arrays of graphitic carbon materials with cylindrical shapes. Multiple pentagons were synthetically embedded in cylinder‐shaped molecules to obtain segments of haeckelite nanotubes with imperfect honeycomb arrays. In these cylinder‐shaped molecules, conjugation was observed over the pentagon bridges. These compounds also provide intermediate structures for retrosynthetic analysis and inspiration for novel defective carbon nanotubes.