Preparation of the Water-Soluble Pyrene-Containing Fluorescent Polymer by One-Pot Method

A new water-soluble pyrene-containing fluorescent polymer, 1-{31-S-[poly(acryloyl ethylene diamine hydrochloride)-21-methyl propionic acid]}propionyloxy hexyloxy pyrene (P3) with defined structure, was designed and synthesized using the click reaction between thiol and a carbon-carbon double bond. The intermediate products P1 (S-1-dodecyl-S1-[poly(N-Boc-acryloyl ethylene diamine)-21-methyl propionic acid]trithiocarbonate) and AHP (1-(acryloyloxy hexyloxy)pyrene) were prepared via reversible addition fragmentation chain transfer (RAFT) polymerization and Williamson synthesis, respectively. Conjugating AHP with P1, P2 (1-{31-S-[poly(N-butoxycarbonyl-acryloyl ethylene diamine)-2”-methyl propionic acid]} propionyloxy hexyloxy pyrene) was synthesized, adopting both the reduction reaction of a trithioester bond of P1 to thiol and the click reaction between thiol and the carbon-carbon double bond of AHP simultaneously. P3 was obtained by the deprotection of the resulting Boc-protected polymer (P2) with aqueous HCl. The experiment results showed that P2 exhibited a bright blue-violet emission band at approximately 387–429 nm. After deprotection, P3 displayed good solubility in water and not only exhibited a blue-violet fluorescence emission band at approximately 387–429 nm in aqueous solution but also had the similar photoluminescent spectra to those of AHP and P2 in dichloromethane. The fluorescence quantum yields of P2 in dilute tetrahydrofuran and P3 in a dilute aqueous solution were 0.44 and 0.39, respectively. This experiment provided a novel insight into the study of water-soluble fluorescent polymers.