Ring reconstruction on a trichalcogenasumanene buckybowl: a facile approach to donor-acceptor-type [5-6-7] fused planar polyheterocycles.
The transformation of trichalcogenasumanene buckybowls into donor-acceptor-type [5-6-7] fused polyheterocycles is disclosed. The strategy involves a highly efficient ring-opening of the flanking benzene upon oxidation at room temperature, and facile ring closure by functional-group transformation. Crystallographic studies indicate that the resulting [5-6-7] fused polyheterocycles possess a planar conformation owing to the release of ring strain by expansion of one of the six-membered flanking rings to the seven-membered one. Additionally, the [5-6-7] fused polyheterocycles bear electron-withdrawing groups, which reduce the HOMO-LUMO energy gap, and display broad absorption bands extending to λ=590 nm. Consequently, these compounds show strong red emission with fluorescence quantum yields of up to 38 %.
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Tianshui Southern Road 222, Lanzhou 730000 (China).
Xuexiang
X
Li
Yongtao
Y
Zhu
Jiafeng
J
Shao
Lichuan
L
Chen
Sijie
S
Zhao
Baolin
B
Wang
Shangxi
S
Zhang
Yongliang
Y
Shao
Hao-Li
HL
Zhang
Xiangfeng
X
Shao
arenes; donor-acceptor systems; fused-ring systems; oxidation; structure elucidation