Optically active methacrylic copolymers bearing side-chain bisazoaromatic and bulky achiral moieties

The synthesis of two novel series of optically active methacrylic copolymers that contain a side-chain chiral moiety linked to a photochromic bisazoaromatic chromophore has been carried out by radical copolymerization of the monomer (S)-3-methacryloyloxy-1-[4'-phenylazo-(4-azobenzene)]pyrrolidine with highly sterically hindered monomers such as tert-butyl methacrylate or triphenylmethyl methacrylate with the aim to investigate the effect on the optical activity of the resulting derivatives. The copolymeric products have been fully characterized and their spectroscopic and thermal properties compared to those of the related optically active homopolymer and the copolymers with methyl methacrylate, previously reported. The optical activity displayed by the polymers is discussed in terms of extent of chiral conformations assumed by the macromolecules as a consequence of the insertion of co-monomers capable of affecting the dipole-dipole interactions that occur in these derivatives between the side-chain bisazoaromatic chromophores disposed according to a mutual chiral arrangement.