The Study Of Synthesis And Properties Of Cyclophane-type Macrocycles

As supramolecular chemistry is developing rapidly in recent years, macrocyclic compounds have been widely applied in molecular recognition, supramolecular polymers, molecular devices, self-assembled micro/nano materials and other fields. Cyclophanes, which consist of an rigid aromatic unit and a flexible aliphatic chain, are one important kind of macrocyclic compounds due to their specific properties and functions. They have the excellent properties of recognizing inorganic and organic cations, anions and neutral substrates strongly and selectively. Furthermore, they can also be used as platforms for construction of complex supramolecular systems (e.g., rotaxanes and catenanes). So it is of great importance to develop a convenient and efficient route for the synthesis of macrocycles. Nowadays, the preparation of cyclophane-type macrocyclic compounds mainly includes:high dilution method and template method. Certain disadvantages of the high dilution method are poor yields of the cyclization, troublesome operation, long reaction time and the requirement of large amounts of solvent. On the other hand, the template method may have some advantages, such as less raw material, short reaction time, high yields and so on. But it still has significant drawbacks:the requirements to introduce and remove the template, which increases the difficulty of the synthesis. Considering all the shortcomings aforementioned, in this paper, we have designed a convenient and efficient synthetic route for the synthesis of cyclophanes based on intramolecular hydrogen bond, and by this method many cyclophane-type macrocycles containing novel skeletons were synthesized, and then molecular switch and self-assembly properties were also studied based on their special structures. The main contents are shown as following:1. The synthesis of cyclophane-type macrocycles:we designed a new synthetic route for the synthesis of cyclophanes based on intramolecular hydrogen bond, and cyclophane-type macrocycles P1-3were synthesized by using di(acid chloride) containing isobutenyl moiety reacted with diamine derivatives. The results revealed, during the experimental process, the influence of diamine derivatives with different molecular chains and rigidity on the selectivity and yield of the reaction was investigated, the molecular chain which is too long or two short could decrease the yield of cyclization, and the rigid structure of diamine derivatives could also decrease the yield of cyclization. On the other hand, the impact of the initial configuration of di(acid chloride) on intramolecular macrocyclization was discussed, the isobutenyl group might play an important role to form key intermediate, which can effectively improve the yield of cyclization. 2. The study of molecular switch performance of cyclophane-type macrocycles:The molecular switch performance based on the reversible reaction between isobutenylene chain and hydroxy group of macrocycle compounds Pl-3induced by Hg2+and NaBH4was investigated. The results revealed that these three macrocycle compounds present different mechanisms for the above process since the effect of the ring-size of macrocycle. Macrocycle PI has molecular switch performance since macrocycle PI can occur reversible reaction. However, macrocycles P2、P3don’t have molecular switch performance since macrocycles P2、 P3aren’t able to occur reversible reaction.3. The self-assembly behaviors of macrocyclic compounds:The fluorescence emission spectrum of macrocycles Pl-3in DMSO changing with various concentration was studied, and the result illustrates that macrocycles P1-3all aggregate in high concentration. Then the self-assembly behaviors of macrocycles P1-3in different solvents were discussed, and the morphologies assembled in solution were observed by scanning electron microscope. Finally, the particle size of macrocycles P1-3was measured by using dynamic light scattering (DLS) technique, which further provides evidence of the aggregation of macrocycles Pl-3in the liquid phase.