Synthesis, Crystal Structure Of Dendritic Compounds And Simulation Of Pseudorotaxanes

The cyclophanes based on 4, 4′- bipyridinium are important compon- ents in supramolecular chemistry. When molecular components become parts of a supramolecular structure, their photo-physical, photo-chemical and electro-chemical properties undergo controllable changes which make the cyclophanes mentioned above become appealing materials for the construction of molecular-level machines.There are various methods to synthesis those compounds in literature, however, Bi-fused deficient-electron bipyridine cyclophane and interme- diates of Bi-fused cyclophane have been reported scarcely. In the experimental part of this dissertation, It was focused on the preparation methods of the intermediates of Bi-fused cyclophane which will be useful tool for synthesis our target product—Bi-fused deficient-electron bipyridine cyclophane. Some new synthesized compounds such as compound 2,2′-(p-Phenylenedimethylene)bis(propane-1,3-diol),1,4- Bis[3-chloro-2-(chloromethyl)-propyl]benzene,Tetraethyl 2, 2′- (2, 3, 5, 6-tetrafluoro-p-phenylenedimethylene)dipropanoate which had not only been proved by the dates of IR, MS, 1H NMR, et al, but also been characterized by X-ray single crystal diffraction. The results of the X-ray single crystal diffraction not only gave more stereo-structure information than the dates of 1H NMR, but also revealed the weak interactions which are crucial to the compounds in crystal packing in the single-crystal structures.As a rapidly growing up method of molecular simulation, molecular dynamics (MD) has been widely used to calculate thermodynamic and dynamic properties as well as structures of many systems. The molecular simulation part of this dissertation, It was focused on studying the intermolecular weak interactions of Pseudorotaxanes which were combined by electron acceptor cyclobis(paraquat-phenylene)tetracationic cyclophane (CPQT) with different electron donating phenyl ether derivatives. Both simulation methods of Quantum Mechanics and Molecular Dynamics were used in modeling and comparing the structure before the interactions occur and the interactions exist. This work was intended to find out the forming mechanism of Pseudorotaxanes in a new way. The structure of CPQT was optimized by AM1 and DFT/B3LYP/ 6-31+g. Charges generated by the material studio software automatically were substituted by calculated charges at B3LYP/6-31+g level. Results show that the order of binding energies for the three phenyl ether derivatives and CPQT are as follows: BHEEB·CPQT> BHEB·CPQT> 1/4DMB·CPQT. Stabilities of the pseudorotaxanes are found to decrease as the temperature increases. These simulated results are consistent with reported experimental results.