Trinitrobenzene sulfonic acid sodium salt

When supramolecular polymers are treated with bulky stopper groups, they may form poly[2]rotaxane daisy chains [32,60-68]. Cyclic tri[2]rotaxanes (daisy chain necklace) containing cyclodextrins have been prepared from the mixture of 6-(4-aminocinnamoyl)-Q -CD and 2,4,6-trinitrobenzene sulfonic acid sodium salt [50,59] in an agueous solution (Fig. 21). If the molecule changes its conformation (or co-conformation), the ring may expand or shrink by external conditions (temperature, solvents, photochemically, elec-trochemically). These compounds are important because the cycle can be used as a chemical valve as seen in ion channels in biological membranes. 

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