Ring Opening Metathesis Polymerization Reaction of Norbornene Derivatives

DNA molecules are double stranded polymers and the most important property for DNA molecules is replication. Hence, the purpose of this thesis is to synthesize double stranded polymers and further test the possibility to mimic DNA replication. Tacticity plays an important role in synthesizing a double stranded polymer. Hence, a range of polynorbornenes having different pending groups at 2,3-endo position by Grubbs’ ruthenium catalyzed polymerization was synthesized. It appears that Grubbs catalyst has a better selectivity than Grubbs II catalyst towards the tacticity of polymer. In addition, the monomeric norbornenes may also influence the stereochemistry of polymers. According to previous research, bis-norbornene monomer containing ferrocene linking group might lead to the formation of the double stranded polymer. Compared to Ferrocene linking group, the square planar platinum complex is a rigid linking group. It seems likely that the polymer obtained form bis-norbornene monomer containing platinum linking group might also adopt double stranded structure. On the other hand, two monomeric bisnorbornenes containing di-ester linking groups were synthesized for the sake of mimicking the process of DNA replication. The corresponding polymers can be obtained through ROMP. It is envisaged that the hydrolysis or reduction of the ester groups of these polymers might afford two single stranded polymers. Unfortunately, the transformation of theses polymers to the corresponding singe stranded polymers was unsuccessful. The failure might arise from the insolubility of these polymers. Finally, an unexpected reaction has been found during the synthetic process. In the presence of Aluminum oxide, acetic acid 4-dimethylamino-benzyl ester and its related compounds will transform to tetra-N-methyl-4,4’-methanediyl-bis-aniline type products.