Balan Haripriya, Sureshan Kana M
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, 695551, India.
Nat Commun. 2024 Aug 5;15(1):6638. doi: 10.1038/s41467-024-51051-z.
Designing and synthesizing flawless two-dimensional polymers (2D-Ps) via meticulous molecular preorganization presents an intriguing yet challenging frontier in research. We report here the single-crystal-to-single-crystal (SCSC) synthesis of a 2D-P via thermally induced topochemical azide-alkyne cycloaddition (TAAC) reaction. A designed monomer incorporating two azide and two alkyne units is synthesized. The azide and alkyne groups are preorganized in the monomer crystal in reactive geometries for polymerizations in two orthogonal directions. On heating, the polymerizations proceed in a hierarchical manner; at first, the monomer reacts regiospecifically in a SCSC fashion to form a 1,5-triazolyl-linked 1D polymer (1D-P), which upon further heating undergoes another SCSC polymerization to a 2D-P through a second regiospecific TAAC reaction forming 1,4-triazolyl-linkages. Two different linkages in orthogonal directions make this an architecturally attractive 2D-P, as determined, at atomic resolution, by single-crystal X-ray diffraction. The 2D-P reported here is thermally stable in view of the robust triazole-linkages and can be exfoliated as 2D-sheets.
通过精心的分子预组装来设计和合成完美的二维聚合物（2D-Ps），是一个引人入胜但具有挑战性的研究前沿领域。我们在此报告通过热诱导拓扑化学叠氮化物-炔烃环加成（TAAC）反应实现二维聚合物的单晶到单晶（SCSC）合成。合成了一种包含两个叠氮基和两个炔基单元的设计单体。叠氮基和炔基在单体晶体中以反应性几何构型预组装，以便在两个正交方向上进行聚合反应。加热时，聚合反应以分层方式进行；首先，单体以SCSC方式区域特异性反应形成1,5-三唑基连接的一维聚合物（1D-P），进一步加热时，通过第二次区域特异性TAAC反应形成1,4-三唑基连接，该一维聚合物再经历另一次SCSC聚合反应生成二维聚合物。如通过单晶X射线衍射在原子分辨率下所确定的，在正交方向上的两种不同连接方式使得这种二维聚合物具有吸引人的结构。鉴于其坚固的三唑连接，本文报道的二维聚合物具有热稳定性，并且可以剥离成二维薄片。
