Synthesis And Properties Of Polymer Containing1,3,4-Oxadiazole And Azobenzene(Quinoline) Unit

In the first part, design and synthesis a new compound of5-[8-hydroxyquinolineazo]-1,3-diethyl isophthalic, then the polymer monomer of5-[8-（alkoxy） quinolineazo]-1,3-dibenzoylhydrazine was obtained by alkylation and ammonolysis reaction. Polymers（P1^P4）containing azobenzene（quinoline） and1,3,4-oxadiazole unit were synthesized by a two-steppolycondensation reactions with compound6and four dichlorides. The structures ofintermediates and polymers were confirmed by IR, UV-vis and1H NMR. The molecularweight of intermediates4and5were tested by ESI-MS.In the second part, the solubility、thermodynamic and optical properties of intermediatsand polymers were investigated. The molecular weights and molecular weight distributions ofthe polymers were determined by gel permeation chromatography（GPC）. The number-average molecular weight（M_n） are2789-12457g/mol, the weight-average molecularweight（M_w） are5021-29174g/mol, and the polydispersity index（PDI） are1.80-2.34,respectively. The thermal stability of polymers are characterized by TG-DTA, the5%weightloss of pre-P1^pre-P4are186-271℃, and P1^P4are241-302℃, respectively, which showthat pre-polymers and polymers has good thermal stability. The introduction of long chain ofalkoxy azobenzene significantly improves polymers’（P1^P4） solubility in common organicsolvents such as THF、DMF、DMAc、DMSO and NMP etc. The trans-cis photoisomerizationof the intermediate4、pre-P1and pre-P2were taken place under the radiation of365nm UVlight. It shows that the trans-cis photoisomerization is unobvious due to the larger sterichindrance of quinoline. Fluorescence emission spectrum of the intermediates, pre-polymersand polymers show that the fluorescence emission width peak of intermediates4⁶arelocated at434-464nm in DMF solution (4×10^-5g/mL), pre-P1^pre-P4and P1^P4are locatedat462-467nm and453-466nm in NMP solution (3×10^-5g/mL), respectively. The results showthat intermediates, pre-polymers and polymers are all blue fluorescence emission. In thispaper, The synthesis of polymers with azobenzene（quinoline） and1,3,4-oxadiazole uniteshow good solubility, good thermal and fluorescence property, which have potentialapplication value in the filed of optical and electrical functional polymer field.