New polyacrylates with stilbene and (S)-phenylalanine side chains for sensor applications. Synthesis and properties

A new acrylic monomer bearing trans-stilbene in structure, (S)-N-acryloylphenylalanine acid 4-styryl-benzyl ester (AcPheS), was prepared to be further free radically copolymerized with (S)-N-acryloylphenylalanine (AcPhe). The resulting copolymer, poly((S)-N-acryloylphenylalanine-co-(S)-N-acryloylphenylalanine acid 4-styryl-benzyl ester) (PPheS) was characterized by 1H NMR, UV–vis and FTIR spectroscopy, thermal analysis, GPC and specific optical rotation measurements. The copolymer composition was estimated from the NMR analysis, this being of 4:1 (AcPhe:AcPheS). The photobehavior of the copolymer in solution and thin film was evaluated comparatively to that of the parent monomer using UV–vis spectroscopy, and atomic force microscopy (AFM) for the polymeric film exposed to UV irradiation. Quenching of the stilbene species by purine and pyrimidine bases in DMF solution excited at 267 nm and 334 nm was evidenced, more efficiently being adenine.