Strain‐Sensitive On‐Surface Ladderization by Non‐Dehydrogenative Heterocyclization
Strain‐Sensitive On‐Surface Ladderization by Non‐Dehydrogenative Heterocyclization
复制标题
通过非脱氢杂环化进行应变敏感的表面阶梯化
DOI：
10.1002/chem.202203622
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Kawai Shigeki
中科院分区：
文献类型：
--
作者：
Ma Yujing;Sugawara Kazuma;Ishigaki Yusuke;Sun Kewei;Suzuki Takanori;Kawai Shigeki
近几年来，表面环脱氢反应成为π共轭分子和低聚物平坦化的重要反应。然而，裂解C−H键的高活性势垒往往需要高温热处理，从而限制了前体分子的结构和/或导致它们边缘的随机融合。在这里，我们提出了一种用键分辨扫描隧道显微镜从11，11，12，12‐tetrabromo‐1，4，5，8‐tetraaza‐9，10‐anthraquinodimethane分子在Ag表面合成吡咯桥联的梯形低聚物的方法。吡嗪和乙炔/异丁烯之间的这种非脱氢环化反应对形成含有二吡嗪并吡咯并吡喃单元的中间二聚低聚物具有较低的活化势垒，从而为梯形齐聚物形成的应变敏感性提供了新的见解。
On‐surface cyclodehydrogenation recently became an important reaction to planarize π‐conjugated molecules and oligomers. However, the high‐activation barrier to cleave the C−H bond often requires high‐temperature annealing, consequently restricting structures of precursor molecules and/or leading to random fusion at their edges. Here, we present a synthesis of pyrrolopyrrole‐bridged ladder oligomers from 11,11,12,12‐tetrabromo‐1,4,5,8‐tetraaza‐9,10‐anthraquinodimethane molecules on Ag(111) with bond‐resolved scanning tunnelling microscopy. This non‐dehydrogenative cyclization between pyrazine and ethynylene/cumulene groups has a low‐activation barrier for forming intermediary dimeric oligomer containing dipyrazinopyrrolopyrrolopyrazine units, thus giving new insight into the strain‐sensitive in ladder‐oligomer formation.