The Host-Guest Chemistry Based On Naphtho-21-Crown-7

The preparation of supramolecular threaded structures based on the host-guest recognition is an attractive topic in supramolecular chemistry. Crown ethers and their derivatives can bind secondary dialkylammonium salts and pyridinium salts with strong complexation ability. These recognition motifs have been widely used as building blocks to construct various supramolecular assemblies, such as rotaxanes, catenanes, molecular devices and molecular machines. These mechanical interlock structures. have widely perspectives and potential applications due to their novel topological structures and properties.As we know, the recognition capability between host and guest compounds is a decisive aspect in the preparation of threaded structures. The effort to improve the host-guest complexation is expanding in recent years not only for the design of new host-guest systems, but also for the modification of known host-guest systems.This thesis was mainly focused on the recognition interaction of a new host naphtho-21-crown-7 and secondary dialkylammonium salts. In acetone solution, the host can effectively recognize secondary dialkylammonium salts (such as di-n-butylammonium hexafluorophosphate, benzyl-n-butylammonium hexafluorophosphate, o-methoxybenzyl-n-butylammonium hexafluorophosphate, o-benzonitrile-n-butylammonium hexafluorophosphate) to form complexes which are slow-exchange systems. We also found the difference of binding affinity and binding selectivity between crown ether and its complementary guest moieties could be affected by the aromatic stacking effect in the recognition motif.The thesis also did few works in threaded structures of crown ethers and secondary dialkylammonium salts based on self-sorting. We designed a linear molecule with three secondary dialkylammonium salt units. Benzo-21-crown-7 and dibenzo-24-crown-8 worked as hosts. This project is proceeding smoothly.