title: Threaded structures based on the benzo-21-crown-7/secondary ammonium salt recognition motif using esters as end groups.
abstract: It was demonstrated that various threaded structures could be constructed by employing different esters as end groups based on the benzo-21-crown-7/secondary ammonium salt recognition motif. The chemical structures of all synthesized compounds were confirmed by (1)H and (13)C NMR spectroscopy as well as mass spectrometry. Single crystal X-ray analysis revealed that all compounds are threaded structures in the solid state. NMR experiments distinguished the rotaxane-like entities from [2]rotaxanes. The threaded structures capped by linear n-alkyl end groups are rotaxane-like entities. The gradual elongation of the ester alkyl chain tails results in the increased stability of the corresponding threaded structures. When the tail is an isopropyl group, a mechanically interlocked rotaxane can be constructed.
authors: Center for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors: Bo
authors: B
authors: Zheng
authors: Mingming
authors: M
authors: Zhang
authors: Xuzhou
authors: X
authors: Yan
authors: Feihe
authors: F
authors: Huang