Dynamically capped rotaxanes: metal coordination vs. acid–base pairing in the chiral end-capping
A series of pseudorotaxanes were formed by mixing a thread molecule and several crown ethers. Crystal structure analysis clearly indicated that hydrogen bonding between NH2
+ of the thread molecule and crown ether oxygen atoms was significantly involved, together
with cation–dipole interactions between cationic nitrogen and ether oxygen atoms. End-capping of the pseudorotaxane with chiral metal complexes gave dynamically capped rotaxanes including dibenzo-24-crown-8. This exhibited induced circular dichroism signals around the benzo-crown and
anthracene-thread chromophore regions, while a chiral organic acid formed rotaxane exhibiting weaker signals.
Keywords: acid–base pairing; chirality; dynamic capping; metal coordination; rotaxane
Document Type: Research Article
Affiliations: 1: Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan 2: Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
Publication date: 01 March 2011
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