Preparation and characterization of novel optically active nanostructured poly(amide–imide)s-containing ( l )-α-amino acid moieties and azobenzene side groups

A series of optically active poly(amide–imide)s (PAI)s-containing photochromic azobenzene moieties as side groups were synthesized. These chiral polymers were derived from monomers-based (l)-α-amino acids such as alanine, isoleucine, methionine, and phenylalanine. Azo-containing diamine 7 was synthesized from the reaction of 4-aminoazobenzene and 3,5-dinitrobenzoyl chloride, followed by the reduction in dinitro with iron oxide hydroxide catalyst and hydrazine monohydrate. The novel PAIs were prepared by direct polycondensation under green medium. The synthesized PAIs, with inherent viscosities of 0.43–0.85 dL g⁻¹, were obtained in high yields. The structures of them were confirmed by elemental analysis, Fourier transform infrared spectroscopy, and proton and carbon nuclear magnetic resonance spectroscopy techniques. The resulting PAIs were also characterized by x-ray diffraction, field emission scanning electron microscopy, ultraviolet–visible spectroscopy, and thermogravimetric analysis techniques. Morphology probes showed that these PAIs were nanostructured polymers and the particle size was around 40–90 nm.