Synthesis and Characterization of Degradable Water-Soluble Fluorescent Polymers

The synthesis and characterization of a water-soluble nonconjugated polymer (PMFT) that was obtained by polymerization of a fluorescence generating diol monomer with terephthalic acid was investigated. The mixture of compound 1 (1.25 g, 1.87 mmol) and compound 2 (760 mg, 5 mmol) in THF (10 mL) and 2.0 M aqueous K2CO3 solution (8 mL) was charged with argon for 30 min. The crude product was extracted with 50 mL of CHCl3 for three times. The combined organic phase was washed with brine and dried over anhydrous MgSO4, and the solvent was removed under vacuum. The photostability of PMFT was studied under UV irradiation with 365 nm as light source. The fairly good photostability of PMFT makes it possible for fluorescence imaging use. The degradation of PMFT was verified by 1H NMR spectroscopy through following the proton chemical shift of the benzyl -CH2- group adjacent to the ester moiety in PMFT (5.47 ppm) to 4.56 ppm for the methylene proton resonance in the MF degradation product.