Synthesis of Stable Nanographenes with OBO-Doped Zigzag Edges Based on Tandem Demethylation-Electrophilic Borylation

A tandem demethylation-aryl
borylation strategy was developed to
synthesize OBO-doped tetrabenzo­[a,f,j,o]­perylenes
(namely “bistetracenes”) and tetrabenzo­[bc,ef,kl,no]­coronenes (namely “peritetracenes”). The OBO-doped
bistetracene analogues exhibited excellent stability and strong fluorescence,
in contrast to the unstable all-carbon bistetracene. Single-crystal
X-ray analysis for OBO-doped bistetracene revealed a twisted double
[5]­helicene structure, indicating that this synthesis is applicable
to new heterohelicenes. Importantly, cyclodehydrogenation of the bistetracene
analogues successfully produced the unprecedented heteroatom-doped
peritetracenes, which opened up a new avenue to periacene-type nanographenes
with stable zigzag edges.

一种串联的脱甲基化-芳基硼化策略被开发出来，用以合成掺杂OBO的四苯并[a,f,j,o]芘（简称“双四苯烯”）和四苯并[bc,ef,kl,no]冠烯（简称“围四苯烯”）。掺杂OBO的双四苯烯类似物展现出卓越的稳定性和强烈的荧光，与不稳定的全碳双四苯烯形成鲜明对比。对于掺杂OBO的双四苯烯的单晶X射线分析揭示了扭曲的双[5]螺旋结构，表明这种合成方法适用于新型异螺旋结构。值得注意的是，双四苯烯类似物的环脱氢化成功制备了前所未有的掺杂杂原子围四苯烯，为具有稳定之字形边缘的近邻苯型纳米石墨烯开辟了新的途径。