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Triptycene‐Derived Oxacalixarenes as New Wheels for the Synthesis of [2]Rotaxanes: Acid–Base‐ and Metal‐Ion‐Switchable Complexation Processes
Author(s) -
Hu ShuZhen,
Chen ChuanFeng
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201003545
Subject(s) - triptycene , chemistry , diastereomer , stereochemistry , dissociation (chemistry) , base (topology) , crystallography , rotaxane , supramolecular chemistry , solid state , metal , nuclear magnetic resonance spectroscopy , polymer chemistry , crystal structure , organic chemistry , mathematical analysis , mathematics
A pair of triptycene‐derived oxacalixarenes, 1 a and 1 b , containing two naphthyridine subunits have been synthesized by a convenient one‐pot approach. Macrocycles 1 a and 1 b are diastereomers, with 1 a being a cis isomer with a boat‐like 1,3‐alternate conformation and 1 b being a trans isomer with a curved boat‐like conformation in the solid state. Both 1 a and 1 b have fixed conformations in solution at room temperature, as revealed by variable‐temperature 1 H NMR spectroscopy experiments. It was found that oxacalixarenes 1 a and 1 b could both form 1:1 [2]pseudorotaxane‐type complexes with paraquat derivatives with different functional groups in solution and in the solid state, which resulted in the further synthesis of a pair of novel isomeric [2]rotaxanes. Moreover, the controlled dethreading and rethreading processes of the [2]pseudorotaxanes were also easily achieved by acid–base stimuli or Hg 2+ association/dissociation.