The Design And Synthesis Of Potential Liquid Crystal Compounds With Optically Active Double Helical Block Buildings

Optically active cyclophanes, such as helical molecules and three-dimensional, dumbbell-like cyclophanes have been the subject of extensive investigation from the standpoints of structural chemistry and material science. This is not only because of their unique structural features (Ï€-conjugated, helicity) and the difficulty of synthesize this kind of compounds. but also because of their potential applications in optics and electronics. In this thesis, based on the preceding research work of our laboratory and plenty of literatures, we synthesize a double helical molecule compound as optically active building block, we also design a series of Liquid Crystal Units such as azobenzene and biphenyl compounds according to plenty of literatures and books on Liquid Crystal, then we use Sonagashira Reaction to join the double helical building block and the LC Units together to get our planed target molecules-optically active Liquid Crystal compounds. On the basis of characterize by some normal methods for the new type optically active LC compounds, we can theoretically investigate the relationship between the structure and the clear point, the range of the L.C Phase and other properties of the compounds.The synthetic routine is composed as following: through the introduction of protective group, then remove the groups, Williamson ether synthesis reaction and the intra-molecular ring-close reaction we can get the optically active double helical block building; also we choose some LC Unit with high performance and easy to produce in our lab based on the literatures and books, we can synthesis these units by means of diazonium salt coupling reaction, Williamson ether synthesis reactions and Suzuki reaction and so on. In the routine we design to get the target molecular, the introduction will involve some Named reactions such as Sonagashira reaction and Suzuki reaction. Pd-and Cu-based salts catalysed coupling reactions—Sonagashira reaction, This coupling reaction could occurred under the catalysis of Pd-and Cu-based salts, between the end alkyne and halogeno-arene (or halogeno-olefin ),this have been discussed in detail in the thesis; but the Suzuki reaction will take place in the existence of Pd(OAc)2 and base, by the reaction we can get the biphenyl derivatives. These reactions have been widely used in the organic synthesis because of its mild condition and high yield.In the first chapter, we will introduce the helical and unique-structured cyclophanes that have been successfully synthesized in our laboratory. They are synthesized by Songashira coupling reaction inter-molecular or intra-molecular with optically active 2 and 2'-positions of 1,1'-bina- phthalene as a template.In the second and the third chapter, we introduce how to prepare basic material. Through Diazotization, Bromonation, Diazotization and Williamson ether reaction from 3,5-dimethylaniline,we prepare the double helical block building for the Target molecular, then through the Diazoium salt coupling reaction and Suzuki reaction we can obtain the azobenzene and biphenyl LC Units respectively.In the last chapter, we have synthesized the target molecule by Sonogashira coupling reaction. Target molecular and intermediates have been identified by ¹H-NMR and ¹³C-NMR.