Issue 1, 2016

Synthesis of open-shell ladder π-systems by catalytic C–H annulation of diarylacetylenes

Abstract

A new open-shell ladder-shaped π-system has been synthesized. Pentaleno[1,2-b:4,5-b′]difluorene derivatives, 8 fused ring systems bearing 5- and 6-membered rings, were constructed from alkynylfluorenone through a reaction sequence including Pd-catalyzed C–H/C–H annulation. X-ray crystallography and ESR spectroscopy revealed the open-shell character of these ladder-shaped molecules, which derives from their extended π-electron conjugation. Absorption peaks in the near IR region as well as narrow redox potentials observed by cyclic voltammetry indicated small optical and fundamental energy gaps of these fused ring systems.

Graphical abstract: Synthesis of open-shell ladder π-systems by catalytic C–H annulation of diarylacetylenes

Supplementary files

Article information

Article type
Edge Article
Submitted
09 Sep 2015
Accepted
20 Oct 2015
First published
22 Oct 2015
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2016,7, 650-654

Author version available

Synthesis of open-shell ladder π-systems by catalytic C–H annulation of diarylacetylenes

T. Maekawa, H. Ueno, Y. Segawa, M. M. Haley and K. Itami, Chem. Sci., 2016, 7, 650 DOI: 10.1039/C5SC03391H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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