西班牙马德里康普顿斯大学Nazario Martín研究组的最新研究提出了螺旋排列的手性分子纳米石墨烯。该研究于2021年7月20日发表于国际一流学术期刊《美国化学会杂志》上。

本文报道了两种正交二苯并[fg,ij]菲[9,10,1,2,3-pqrst]五苯(DBPP)基四氟环共价连接的分子纳米石墨烯的溶液相合成方法。这三个共价键连接的分子片段的螺旋排列导致了手性轴的存在，从而产生外消旋混合物，即使分子部分被对称取代。

x射线衍射研究表明，这两种对映体在单晶中共结晶，且外消旋混合物可以用手性高效液相色谱法拆分。DBPP基的不对称取代产生了一对非对映异构体，其旋转异构化已通过¹H NMR研究。此外，电化学和光物理性质从这些新的分子纳米石墨烯揭示了电活性特性和显著的荧光行为。

附：英文原文

Title: Helically Arranged Chiral Molecular Nanographenes

Author: Patricia Izquierdo-García, Jesús M. Fernández-García, Israel Fernández, Josefina Perles, Nazario Martín

Issue&Volume: July 20, 2021

Abstract: A benchtop solution-phase synthesis of molecular nanographenes composed of two orthogonal dibenzo[fg,ij]phenanthro[9,10,1,2,3-pqrst]pentaphene (DBPP) moieties covalently connected through a tetrafluorobenzene ring is described. The helical arrangement of these three covalently linked molecular fragments leads to the existence of a chiral axis which gives rise to a racemic mixture, even with the molecular moieties being symmetrically substituted. X-ray diffraction studies show that both enantiomers cocrystallize in a single crystal, and the racemic mixture can be resolved by chiral HPLC. Asymmetric substitution in DBPP moieties affords a pair of diastereoisomers whose rotational isomerization has been studied by 1H NMR. Additionally, the electrochemical and photophysical properties derived from these new molecular nanographenes reveal an electroactive character and a significant fluorescent behavior.

DOI: 10.1021/jacs.1c05977

Source: https://pubs.acs.org/doi/10.1021/jacs.1c05977