Koner Kalipada, Karak Suvendu, Ogaeri Yutaro, Nishiyama Yusuke, Banerjee Rahul
Centre for Advanced Functional Materials, Department of Chemical Science, Indian Institute of Science Education and Research, Kolkata, Mohanpur, 741246, India.
RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan.
Angew Chem Int Ed Engl. 2023 May 8;62(20):e202300652. doi: 10.1002/anie.202300652. Epub 2023 Apr 12.
Covalent organic nanotubes (CONTs) are porous one-dimensional frameworks connected through imine bonds via Schiff base condensation between aldehydes and amines. The presence of two amine groups at the ortho position in the structurally demanding tetraaminotriptycene (TAT) building block leads to multiple reaction pathways between the ditopic aldehyde and the tetratopic amine. We have synthesized five different monomers of CONT-1 by the Schiff base condensation reaction between TAT and o-anisaldehyde. The conversion of imine to imidazole bonding in a monomer is probed using NMR, mass spectrometry, and X-ray diffraction techniques. Solid-state NMR provide insights into the CONTs' structural connectivity. A theoretical investigation suggests that the π-π stacking could be the driving force for rapid imine to imidazole conversion within the CONT-1. Microscopic imaging sheds further light on the self-assembly process of the CONTs, indicating both head-to-head and side-by-side assembly.
共价有机纳米管（CONTs）是通过醛与胺之间的席夫碱缩合反应经亚胺键连接而成的多孔一维框架结构。在结构要求较高的四氨基三蝶烯（TAT）结构单元的邻位存在两个氨基，这导致了双位醛与四位胺之间存在多种反应途径。我们通过TAT与邻茴香醛之间的席夫碱缩合反应合成了五种不同的CONT-1单体。利用核磁共振（NMR）、质谱和X射线衍射技术探究了单体中亚胺向咪唑键的转化。固态核磁共振提供了关于CONTs结构连通性的见解。理论研究表明，π-π堆积可能是CONT-1内亚胺快速转化为咪唑的驱动力。微观成像进一步揭示了CONTs的自组装过程，表明存在头对头和并排组装方式。
