Furan-containing double tetraoxa[7]helicene and its radical cation
Hao Chang, Haoliang Liu, Evgenia Dmitrieva, Qiang Chen, Ji Ma, Piao He, Pengcai Liu, Alexey A. Popov, Xiaoyu Cao, Xiaoye Wang, Yingping Zou, Akimitsu Narita, Kläus Müllen, Hongjian Peng, Yunbin Hu
Abstract
An unprecedented furan-based double oxa[7]helicene 1 was achieved, featuring a stable twisted conformation with π-overlap at both helical ends. The excellent conformational stability allowed for optical resolution of 1, which provided a pair of enantiomers exhibiting pronounced mirror-imaged circular dichroism and circularly polarized luminescence activity. The radical cation of 1 was obtained by chemical oxidation as evidenced by UV-Vis-NIR absorption, electron paramagnetic resonance spectroscopy and in situ spectroelectrochemistry. The present work is the starting point for the investigation of open-shell oxahelicenes.