Jia Fei, Li Dong-Hao, He Shan, Yang Liu-Pan, Jiang Wei
Shenzhen Grubbs Institute, Guangdong Provincial Key Laboratory of Catalysis, Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China.
Shaanxi Key Laboratory of Chemical Reaction Engineering, College of Chemistry and Chemical Engineering, Yan'an University, Yan'an, 716000, China.
Angew Chem Int Ed Engl. 2022 Nov 7;61(45):e202212305. doi: 10.1002/anie.202212305. Epub 2022 Oct 7.
Unprecedented threading kinetics were revealed between viologen-based guests and conformationally adaptive oxatub[4]arene. Three representative conformations of oxatub[4]arene are involved in the kinetic and thermodynamic products which follow the opposite orders in their rankings. Consequently, error correction was involved and a complex kinetic process was observed in a simple two-component system. Moreover, it was found that some viologen-based guests have much faster threading kinetics than those of DABCO-based with the same stoppers. This was enabled by an unprecedented threading mechanism in which a tilted conformation of the guests is adopted by involving one linear alkyl group on the 3,5-dialkoxybenzyl stoppers, the viologen core, and the methylene spacers in the transition states. This new mechanism even allows the viologen-based guests with the 3,5-dicetyloxybenzyl stoppers to form a pseudorotaxane with oxatub[4]arene.
基于紫精的客体与构象适应性氧杂[4]芳烃之间展现出了前所未有的穿线动力学。氧杂[4]芳烃的三种代表性构象参与到动力学和热力学产物中，它们在排序上遵循相反的顺序。因此，涉及到了误差校正，并且在一个简单的二元体系中观察到了复杂的动力学过程。此外，还发现一些基于紫精的客体的穿线动力学比具有相同封端基的基于三乙烯二胺的客体快得多。这是通过一种前所未有的穿线机制实现的，在该机制中，客体采取倾斜构象，过渡态涉及3,5-二烷氧基苄基封端基上的一个线性烷基、紫精核心和亚甲基间隔基。这种新机制甚至允许具有3,5-二鲸蜡氧基苄基封端基的基于紫精的客体与氧杂[4]芳烃形成准轮烷。
