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A Cholesterol Containing pH‐Sensitive Bistable [2]Rotaxane
Author(s) -
Berg Martin,
Nozinovic Senada,
Engeser Marianne,
Lützen Arne
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201500657
Subject(s) - rotaxane , chemistry , protonation , crown ether , amine gas treating , cationic polymerization , bistability , nuclear magnetic resonance spectroscopy , ether , spectroscopy , polymer chemistry , stereochemistry , photochemistry , organic chemistry , molecule , supramolecular chemistry , ion , physics , quantum mechanics
A non‐symmetrical pH‐sensitive bistable [2]rotaxane that bears a cholesterol unit and a tetraphenylmethane group as stopper groups was designed and synthesized in 18 steps. The successful formation of the rotaxane was proven by NMR spectroscopy and MS/MS. Besides a permanent cationic alkylated triazolium unit, the axle contains a secondary amine that can act as a second pH‐sensitive binding site for a crown ether. Depending on the protonation state of this amine function, the crown ether reversibly changes its position by moving between the two binding sites along the axle, as revealed by NMR spectroscopy.