(5,8)Picenophanedienes: Syntheses, Structural Analyses, Molecular Dynamics, and Reversible Intramolecular Structure Conversion

Min Chih Tang, Yu Chen Wei, Yen Chen Chu, Cai Xin Jiang, Zhi Xuan Huang, Chi Chi Wu, Tzu Hsuan Chao, Pei Hsun Hong, Mu Jeng Cheng, Pi Tai Chou, Yao Ting Wu

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


This study presents an important and efficient synthetic approach to 5,8-dibromo-2,11-di-tert-butylpicene (3), with multigram scale, which was then converted to a new series of picenophanes (6-10). The tub-shaped [2,2](5,8)picenophanediene 8 with two cis-ethylene linkers was explored using X-ray crystallography. The tub-to-tub inversion proceed through the successive bending of the linkers and the barrier for isopropyl-substituted derivative 10 was experimentally estimated to be 18.7 kcal/mol. Picenophanes with a large π-system and semi-rigid structure exhibited anomalous photophysical properties. The ethano-bridged picenophane shows the weak exciton delocalization while the cis-ethylene-bridged picenophane exhibits dual emission rendered by the weakly delocalized exciton and excimer. With the aid of the ultrafast time-resolved emission spectroscopy, the mechanism of the excimer formation is resolved, showing a unique behavior of two-state reversible reaction with fast structural deformation whose lifetime is around 20 ps at 298 K. This work demonstrates that the slight difference in the bridge of tub-shaped picenophanes renders distinct photophysical behavior, revealing the potential of harnessing inter-moiety reaction in the picenophane systems.

Original languageEnglish
Pages (from-to)20351-20358
Number of pages8
JournalJournal of the American Chemical Society
Issue number48
Publication statusPublished - 2020 Dec 2

All Science Journal Classification (ASJC) codes

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


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