转化(遗传学)
阶段(地层学)
单重态
单线态氧
结晶学
立体化学
物理
化学
地质学
量子力学
古生物学
生物化学
氧气
基因
激发态
作者
Jinlian Hu,Qin Xiang,Xiaoqi Tian,Lei Ye,Yanpei Wang,Yong Ni,Xing Chen,Yuxia Liu,Guang Chen,Zhe Sun
摘要
Polycyclic hydrocarbons with diradical and polyradical characters usually display unique reactivities in ring-cyclization reactions. However, such reactions are rarely used to construct π-extended polycyclic aromatic hydrocarbons. Here, we describe the synthesis of an S-shaped doubly helical singlet diradicaloid compound and its facile transformation into an unprecedented circumchrysene via a two-stage ring cyclization, which includes: (1) an eletrocylization from diradicaloid precursor and (2) a Scholl reaction. The reaction mechanism was investigated through in situ spectroscopic studies, assisted by theoretical calculations. This reaction sequence yields an optically resolved π-extended [5]helicene derivative with a fluorescence quantum yield up to 85% and a circularly polarized luminescence brightness up to 6.05 M–1 cm–1 in the far-red to near-infrared regions. This sequence also yielded a highly delocalized circumchrysene molecule, exhibiting large electron delocalization, moderate fluorescence quantum yield, and multistage redox properties.
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