Synthesis And Characterization Of Poly(Phenylene Acetylene) Derivatives

In recent years, conjugated polymers based fluorescent chemosensor has been developed rapidlyfor their high selectivity, sensitivity and stability, with a broad application prospect. Rigid conjugated main chain is an important feature of conjugated polymers, it can formed large conjugatedπelectron system, so that the charge can transfer within the molecule. Thus, a single quencher molecule can cause a super-quenching of the entire polymer chain. Compared with the traditional fluorescent small molecule sensors, the main reason of conjugated polymer used as active sensing material is their specific signal amplification characteristic.Poly-phenylene vinylene and derivatives, poly-phenylene acetylene and its derivatives, polyfluorene, polythiophene and poly benzene and derivatives are commonly used as conjugated polymer ssensing materials.Among them,poly-phenylene acetylene (PPE)have drawn widespread interest due to their high stability,photophysical and non-linear properties. However, the main chain of PPE with the rigid structure of C≡C,so that its solubility is very poor and it is difficult to be processed, in order to get good soluble PPE,we need to introduce long-chain flexible group to improve the polymer solubility in organic solvents.Firstly, this paper combines the results of previous studies, synthesizes three PPE derivatives of aromatic side with different substituents through Sonogashira coupling reaction. These copolymers are characterized by 1H-NMR and FT-IR, and the influence of different benzene ring side chain on the solubility and spectrum of copolymers are studied. it is found that the solubility and film forming property of PPE derivatives has been greatly improved by introducing asymmetric substituents n the benzene ring side chain and the fluorescence intensity does not change significantly.Secondly, this paper studies the interactions between two kinds of nitro-aromatic compounds and the synthesized fluorescent conjugated polymers. The result shows that the PPE derivatives containing two alkoxy side chain have good fluorescence response to nitro-substituted compounds, and the sensitivity of fluorescence quenching becomes larger with the increase of nitro number in compounds.Finally, this paper synthesizes four kinds of PPE derivatives with POSS group,using the advantages of polyhedral silsesquioxane (POSS) in modified polymer material, light-emitting properties and the good electron mobility and rigidity of the poly-phenylene acetylene. These copolymers are characterized by 1H-NMR and F T-IR and their UV-visible absorption and fluorescence spectra properties were studied.