Synthesis And Application Of Having Amide (Hydrazine) Water-soluble Cationic Polythiophene Derivatives

Through years of research and development, water soluble cationic polythiophenederivatives have achieved significant progress in the aspect of theory and applications.Moreover, water soluble cationic polythiophene derivatives have been widely used inchemical, environmental and biomedical sensor probes due to their unique optical, electricaland processable properties.In this paper five new monomers2-[4-(thiophen-3-ylmethylidene)piperidin-1-yl]acetohydrazide,3-[4-(thiophen-3-ylmethylidene)piperidin-1-yl]propanehydrazide,[3-(3-(4,4-dimethylpiperazin-1-yl)-3-oxopropyl)thiophen]bromine,3-(thiophen-3-yl) propanehydrazide andN,N,N-trimethyl-3-(thiophen-3-yl)propenaminium bromide were obtained from4-(thiophen-3-ylmethylidene)piperidine,3-(thiophen-3-yl) propanoyl chloride,3-(thiophen-3-yl) methyl propionate and3-(Thiophen-3-yl) acrylate as starting materials, andthen through substitution, addition, acylation, reduction, esterification, hydrazine solutionreaction and quaternary ammoniation. Then three monomers were polymerized by ferricchloride oxidative polymerization to obtain five new polythiophene derivatives including poly3-{[1-(2-hydrazino-2-oxoethyl)piperidin-4-ylidene]methyl}thiophene (PM1), poly3-{[1-(3-hydrazino-3-oxopropyl)piperidin-4-ylidene]methyl}thiophene (PM2),poly[3-(3-(4,4-dimethylpiperazin-1-yl)-3-oxopropyl)thiophen chloride](P1),poly[3-(5-(3-(3-(4,4-dimethylpiperazin-1-yl)-3-oxopropyl)thiophen-2-yl)thiophen-3-yl)propanehydr-azide chloride](P2) and poly[N,N,N-trimethyl-3-(thiophen-3-yl)propenaminiumchloride](PTPA-Cl). The water-soluble conjugated polyelectrolyte poly3-{[1-(2-hydrazino-2-oxoethyl)piperidin-4-ylidene]methyl}thiophene hydrochloride(PM1·HCl) and poly3-{[1-(3-hydrazino-3-oxopropyl)piperidin-4-ylidene]methyl}thiophenehydrochloride (PM2·HCl) were obtained by the reaction of PM1and PM2with HCl, whichcontain hydrazide functional group. The P2is copolymer with hydrazine and amide functionalgroup. The structures of these monomers and polymers were characterized by NMR and FTIR.Also by ultraviolet visible spectrum UV-Vis and fluorescence emission spectrum (FL) on theoptical properties of the five kinds of water-soluble cationic polythiophene derivatives were studied.Due to the five water soluble cationic polythiophene derivatives possess great opticalproperty, so they were successfully applied as fluorometric probes and visible colorimetricprobe for the detection of nucleotide salts and heavy metal ions in water. The experimentalresults show that the new water-soluble cationic polythiophene derivatives PM1·HCl,PM2·HCl and P2can be used as a fluorescent probe to detect the heavy metal ions in thewater, and showed good selectivity and sensitivity for copper ion and mercury ion. Uponaddition of Cu2+to the PM1·HCl solution, the yellow emission of the fluorescent color of thepolymer solution is blue, upon addition of Hg2+to the PM1·HCl aqueous solution, the yellowemission of the fluorescent color of the polymer solution is brown. Detection limits of sensorPM1·HCl for Cu2+and Hg2+were estimated to be2.0×10-10M and2.0×10-9M, respectively.PM2·HCl has its own optical properties, because it adds one carbon atom at the thiopheneside chain rather than PM1·HCl, so it only showed selective for copper ion. Detection limits ofsensor PM2·HCl for Cu2+was estimated to be2.0×10-10M. PM2showed good selectivity andsensitivity for copper ion, and for copper ion detection was2.0×10-9M. Water solublecationic polythiophene PTPA-Cl can use colorimetric method and fluorescence detectionmethod to detect nucleotide salts, and showed good selectivity and sensitivity for ATP, thedetection limits of sensor PTPA-Cl for ATP estimated to be1.0×10-8M.