Synthesis And Properties Of Conjugated Polythiophene Derivatives

In recent30years, Conductive polymers have achieved significant progress in the aspectof theory and applications, but it still exists many problems in conductive polymer materials.Therefore, from the perspective of its principle and application, the direction of futureresearch and application of conjugated polymers is to overcome the current shortcomings instructure design and to further enhance and improve application performance of this kind ofconductive polythiophene derivatives. Moreover, cationic polythiophene derivatives havebeen widely used in chemical, biological and environmental sensors, biomedical probes dueto their unique optical, electrical and processable properties.Herein, five new monomers3-（N-butyl-4-piperidinemethylene）-thiophene（BLMT）,3-（N-butyryl-4-piperidinemethylene）-thiophene（BRMT）,3-（N-hexyl-4-piperidinemethylene）-thiophene（NHT）,3-（N-caproyl-4-piperidinemethylene）-thiophene（NCT） and N, N, N-trimethyl-4-（thiophen-3-ylmethylene）cyclohexanaminium bromide（TCA-Br） were obtainedfrom3-thienylmethanol as starting materials, and then through bromination, esterification,Witting-Horner reaction and quaternary ammoniation. The structures of these monomers werecharacterized by1H NMR and FTIR. Then three monomers were polymerized by ferric chlorideoxidative polymerization to obtain five new polythiophene derivatives includingpoly[3-（N-butyl-4-piperidinemethylene）-thiophene]（P3BLMT）, poly[3-（N-butyryl-4-piperi-dinemethylene）-thiophene]（P3BRMT）, poly[3-（N-hexyl-4-piperidinemethylene）-thiophene]（P3NHT）, poly[3-（N-caproyl-4-piperidinemethylene）-thiophene]（P3NCT） and poly[N,N,N-trimethyl-4-（thiophen-3-ylmethylene）cyclohexanaminium chloride]（PTCA-Cl）. The structuresof these polymers were characterized by1H NMR, FTIR and GPC, and photoluminescencespectra and UV-vis spectra of the polythiophenes were investigated. In addition, the polymerswere also characterized by cyclic voltammetry and scanning electron microscopy.Due to cationic polythiophene derivatives PTCA-Cl and CCP possess great opticalproperty and water solubility, they were successfully applied as fluorometric probes for thedetection of anionic surfactants and Hg2+. The results showed that PTCA-Cl can be used asgood probe for detecting anionic surfactants and the detection limit is10^-9M. What’s more,copolymer CCP can be used as probe for detecting Hg2+in water and the detection limit is 5×10^-9M. In a word, the two new type of cationic polythiophene derivatives weresuccessfully used as fluorescent probe.