Hu Yunbin, Paternò Giuseppe M, Wang Xiao-Ye, Wang Xin-Chang, Guizzardi Michele, Chen Qiang, Schollmeyer Dieter, Cao Xiao-Yu, Cerullo Giulio, Scotognella Francesco, Müllen Klaus, Narita Akimitsu
Max-Planck-Institut für Polymerforschung , Ackermannweg 10 , Mainz 55128 , Germany.
Department of Organic and Polymer Chemistry, College of Chemistry and Chemical Engineering , Central South University , Changsha , Hunan 410083 , People's Republic of China.
J Am Chem Soc. 2019 Aug 14;141(32):12797-12803. doi: 10.1021/jacs.9b05610. Epub 2019 Aug 2.
A π-extended double [7]carbohelicene with fused pyrene units was synthesized, revealing considerable intra- and intermolecular π-π interactions as confirmed with X-ray crystallography. As compared to the previous double [7]carbohelicene , the π-extended homologue demonstrated considerably red-shifted absorption with an onset at 645 nm (: 550 nm) corresponding to a smaller optical gap of 1.90 eV (: 2.25 eV). A broad near-infrared emission from 600 to 900 nm with a large Stokes shift of ∼100 nm (2.3 × 10 cm) was recorded for , implying formation of an intramolecular excimer upon excitation, which was corroborated with femtosecond transient absorption spectroscopy. Moreover, revealed remarkable chiral stability with a fairly high isomerization barrier of 46 kcal mol, according to density functional theory calculations, which allowed optical resolution by chiral HPLC and suggests potential applications in chiroptical devices.
合成了一种带有稠合芘单元的π-扩展双[7]碳螺旋烯，X射线晶体学证实其存在显著的分子内和分子间π-π相互作用。与之前的双[7]碳螺旋烯相比，这种π-扩展同系物表现出明显的红移吸收，起始波长为645 nm（之前为550 nm），对应较小的光学带隙1.90 eV（之前为2.25 eV）。记录到其在600至900 nm范围内有宽的近红外发射，斯托克斯位移约为100 nm（2.3×10 cm），这意味着激发时形成了分子内激基缔合物，飞秒瞬态吸收光谱证实了这一点。此外，根据密度泛函理论计算，该物质具有显著的手性稳定性，异构化势垒相当高，为46 kcal/mol，这使得可以通过手性高效液相色谱进行光学拆分，并暗示其在旋光器件中的潜在应用。
