Development Of New Recognition Motifs And Preparation Of Molecular Machines Based On Pyridine-containing Crown Ethers

The development of new recognition motifs and the self-assembly of molecular machines have been research hotspots in the field of supramolecular chemisty.In recent years, the pyridine-containing hosts have attracted extensive attention because of their unique characteristics. Based on the achievements in pyridine-containing crown ethers and acid/base controllable molecular machines, this thesis focused on the research and obtained the results as follows:(1) A new and larger pyridine-containing crown ether, DP30C10, was designed and synthesized, and a new recognition motif of DP30C10/DAP salt was developed. Based on this new motif and the bacisity of pyridyls on DP30C10, we also developed an acid/base controllable molecular switch.(2) A new main chain-type polyrotaxane was synthesized by one-pot olefins metathesis polymerization with DP24C8as the host. A molecular machine based on this polyrotaxane was formed via controlling the acidity/bacisity in solution and this linear polyrotaxane was reversibly crosslinked via Pd coordination. This dual stimulate-response mechanically interlocked supramolecular polymer will provide an opportunity to open a new way for the fabrication of environmental response materials.(3) DP24C8and DP30C10dialkene derivatives were synthesized. From these derivatives, an attempt was done to prepare cryptands and [2]rotaxanes using a new method of slipping-then-shrinking via olefins metathesis reaction. Although the corresponding products were not afforded, the trials provided us some valuable experience for the synthesis of these cryptands and the development of the new method for mechanically interlocked molecules.(4) Based on the different recognition ability of DP24C8to dialkylammonium salts/paraquat salts and the difference of acidity/bacisity on the host and guest, we tried to prepare a tristable molecular machine via S-click reaction.