Synthesis and characterization of chiral polythiophenes: Poly [(R)-(−) and (S)-(+)-2-(3′-thienyl)ethyl N-(3″,5″-dinitrobenzoyl)-α-phenylglycinate]

(R)-(−) (1) and (S)-(+)-2-(3′-Thienyl)ethyl N-(3″,5″-dinitrobenzoyl)-α-phenylglycinate (2) monomers were synthesized, characterized, and polymerized in chloroform using FeCl3 as an oxidizing agent. Molecular weights of 2.6 × 104 and 3.2 × 104 for poly1 and poly2, respectively, were determined by SEC analysis. FTIR spectra of the polymers indicated the coupling of monomers through the α positions. UV-vis spectra showed absorption bands at λmax = 226 and 423 nm for poly1 and poly2, ascribed to transitions of side groups and polythiophene backbone, respectively. Poly1 and poly2 remained stable up to 210 °C. At higher temperatures, a two step weight loss degradation process was observed for both polymers by TGA analysis. 1H NMR, in the presence of Eu(tfc)3, and optical rotation measurements indicate the chiral properties of the monomers 1 ([α]D28 = −76.2) and 2 ([α]D28 = +76.0), and the maintenance of chirality after polymerization (poly1 [α]D28 = −29.0 and poly2 [α]D28 = +28.4, c = 2.5 in THF). According to scanning electron microscopic analysis, the polymers are highly porous.