π‑Expanded Coumarins: One-Pot Photo Synthesis of 5H‑Benzo[12,1]tetrapheno[7,6,5-cde]chromen-5-ones and Photophysical Properties
journal contributionposted on 19.02.2020, 21:31 by Wenhao Xue, Ding Wang, Chenyu Li, Zheng Zhai, Tao Wang, Yong Liang, Zunting Zhang
The synthesis of a unique type of π-expanded coumarin derivatives, bearing six fused phenyl rings, was achieved via one-pot Suzuki reaction and visible light-driven electrocyclization. The large π-expanded 5H-benzo[12,1]tetrapheno[7,6,5-cde]chromen-5-ones were obtained in good to high yields from 1-bromo-2H-phenaleno[1,2,3-de]chromen-2-ones, and the intriguing optical properties were explored by altering the attached functional groups. 2-Arylaminosubstituted-5H-benzo[12,1]tetrapheno[7,6,5-cde]chromen-5-ones showed a large Stokes shift (4005 cm–1) or excellent fluorescence quantum yield (Φf = 0.75) along with significant bathochromic shift in tetrahydrofuran.