Preparation and characterization of new optically active poly(N-acryloyl chloride) functionalized with (S)-phenylalanine and pendant pyrene

The synthesis and characterization of the poly(N-acryloyl chloride) derivatives containing amino acid, carboxyl groups and pyrene in the side chain of the backbone introduced by a post-modification with suitable compounds are reported. Alkaline hydrolysis of the ester groups in poly(N-acryloyl (S)-phenylalanine benzyl ester-acrylic acid-acryloyloxymethyl-pyrene) (PAcPheBz-Py) or its reducing with H2 in the presence of Pd/C (10%) was carried out to prepare terpolymers with free carboxyl groups (PAcPhe-Py1, PAcPhe-Py2), whose structure and composition are similar. Investigation of such structures by the fluorescence spectroscopy indicates a clear dependence of the fluorescence on the polymer structure, the solvent nature, temperature and pH, with a significant increasing of the monomer emission upon addition of CH3OH to the PAcPhe-Py1 solution in THF. Varying the composition and the pH of the debenzylated polymer solution, a conformational change reflected through increasing and decreasing of the fluorescence intensity of the side chain fluorophore was evidenced. Also, the sensing capability of the above pyrene-polymers determined by measuring the fluorescence quenching suggested that these acrylate analogues could find practical applications for detection of amine molecules.