Qiu Gege, Khatmi Djamel Eddine, Martinez Alexandre, Nava Paola
Aix Marseille Univ., CNRS, Centrale Marseille, iSm2 Marseille France
Laboratory of Computational Chemistry and Nanostructures, University of 08 May 45 Guelma Algeria.
RSC Adv. 2021 Apr 13;11(23):13763-13768. doi: 10.1039/d1ra01761f.
The key features that govern the chirality transfer in a structurally contracted covalent cage, consisting of a northern chiral cyclotriveratrylene (CTV) connected to a southern tris(2-pyridyl-methyl)amine (TPA) unit by three methyl bridges, are described. The preferential orientation of the propeller arrangement of TPA is dictated by its compact structure, with an arm of the TPA unit pointing inside the cage, together with the relative positioning of the three pyridines regarding the chiral CTV cap. The diastereomers with / (or /) configurations for the CTV and TPA units adopt eclipsed structures and were found to be more stable by 40 kJ mol than the / (or /) diastereomer which displays a staggered arrangement. The existence of isomerization pathways between isomers of the cage with low energy barriers (38 kJ mol) accounts for the H-NMR signal, which is consistent with an averaged structure.
描述了一种结构收缩的共价笼中手性转移的关键特征，该共价笼由一个通过三个甲基桥连接到南部三（2-吡啶基甲基）胺（TPA）单元的北部手性环三藜芦烃（CTV）组成。TPA螺旋桨排列的优先取向由其紧凑结构决定，TPA单元的一个臂指向笼内，同时三个吡啶相对于手性CTV帽的相对位置也是如此。CTV和TPA单元具有 /（或 /）构型的非对映异构体采用重叠结构，并且发现其比显示交错排列的 /（或 /）非对映异构体更稳定40 kJ/mol。笼状异构体之间存在低能垒（38 kJ/mol）的异构化途径，这解释了H-NMR信号，这与平均结构一致。
