Controlling the selective synthesis of [2]- and [3]rotaxanes by intermolecular steric hindrance between the macrocyclic hosts

Controlling the selective synthesis of [2]- and [3]rotaxanes by intermolecular steric hindrance between the macrocyclic hosts†

Zecong Ye,

^a Jian Wang,^a Sudarshana Santhosh Kumar Kothapalli,^a Zhiyao Yang,^a Lixi Chen,

^a Weitao Xu,^b Yimin Cai,^a Tinghui Zhang,^a Xin Xiao,

^b Pengchi Deng,^a Wen Feng

^a and Lihua Yuan

*^a

Author affiliations

* Corresponding authors

^a College of Chemistry, Key Laboratory for Radiation Physics and Technology of Ministry of Education, Analytical & Testing Center, Sichuan University, Chengdu 610064, Sichuan, China
E-mail: lhyuan@scu.edu.cn
Tel: +86-28-85412890

^b Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China

Abstract

Two hydrogen-bonded azo-macrocycles with little disparity of the side chains in steric hindrance exhibited a substantial difference in complexation (slow/fast exchange) towards bipyridinium. Inspired by this finding, these macrocycles were applied to efficiently and selectively construct [2]- and [3]rotaxanes through one-pot synthesis. The origin of the selectivity in this novel approach was elucidated by comparing single crystal structures, DFT calculations and stepwise synthesis.