Poly Acetylenes With Chiral And Tetraphenylethene Modified Side Chain: Synthesis,structures And Properties

In this thesis,two types of aggregation-induced emission(abbreviated as AIE)featured poly acetylenes were successfully synthesized through a unique synthetic route design: AIEgens and chiral centres were integrated into the side chains in a given pattern.Properties including structures,chirality and fluorescence behaviours were investigated.Chapter 1 showed chemical structures and synthesis methods of polyacetylenes.When chiral groups were integrated,such polymers were gifted with a variety of features including circular dichroism,circular plotoluminescence,etc.Besides,conventional fluorescent dyes were also introduced: their large planar conjugation structural properties and aggregation-caused quenching effects.Afterwards,the significance of my tasks were list.In chapter 2,chemical reagents employed in this work and instrumentation methods were list.In the third chapter,four alkyl acetylene monomers containing chiral groups and tetraphenylethene(TPE)units were studied,after which,corresponding homopolymers with great molecular weight(Mw)and proper molecular weight distribution were obtained when a metal-coordinated catalyst Rh+(nbd)[B(C6H6)4]-was used.First,spectral behaviours as well as chiral properties of the monomers were analyzed,suggesting all these substances were of AIE characteristics and chirality.Additionally,spectroscopic results of the polymers indicated that their dilute solution were hardly emissive when water fraction is not as high as 20%.However,when an increasing amount of water was introduced,the fluorescence intensity soared,denoting that all these polymers are AIE active.On the other hand,in the CD spectra,a positive-negative-alternated phenomenon appeared(Cotton Effect),which confirmed that the chirality has been conveyed to the main chain.Moreover,the variation tendency of CD signals was observed when adding poor solvent to the polymer solution.Experimental results suggested the increased amount of the poor solvent diminished the CD response,and for the thin film,however,there is no available CD response.Besides,helical structures were found from the scanning electron microscope images.Encouraged by the fore mentioned positive feedback,a series of phenylacetylene monomers composed of chiral groups and TPE substituents were synthesized and studied in Chapter 4.Likewise,polymerization were carried out with another metal coordinated catalyst – [Rh(cod)2Cl]2,but only one type of homopolymer was yielded,which may be ascribed to the difference on the activity of the monomer's structure.Tests on fluorescence and chirality for the monomers implied all of them are AIE species with chirality.As is expected,the resulted polymer is of AIE features,too.In addition,the plus-minus-alternated pattern appeared in the CD tests,showing it is aggregation-induced circular dichroism characterized.Further research on morphology saw microballs with pores.The fifth chapter of paper experiment and the result has carried on the system summary and discussion.