The Synthesis Of The Poly(Phenylacetylene)s Having Bulky π-conjugated Substituents And The Examination Of The Optical Solution With Their Copolymer Membranes

Three kinds of novel polyphenylacetylene monomers 1, 2 and 3 having two bulky π-conjugated substituents via imine groups were designed and synthesized. The chemical structures of the monomers were characterized by the proton NMR spectra and IR spectrometer. The helix-sense-selective polymerization(HSSP) has been achieved of three monomers by the rhodium complex([Rh(nbd)Cl]2) as catalyst and the(R)-or(S)-phenylethylamine((R)-or(S)-PEA) as cocatalyst, and the conditions of the polymerization were discussed in different system. Finally, the most outstanding polymers with the highest molecular weight were all obtained in the concentration of 0.1mol/L,and in the condition of [Monomer]/[[Rh(nbd)Cl]2] = 100 and [((R)-or(S)-PEA)]/[Monomer]=2.50. The molecular weight and its distribution of the polymers were determined by the Gel Permeation Chromatography(GPC), and the highest molecular weight could reach to 4.5×106. The helical structures of the polymers were confirmed by Circular Dichroism(CD).The structure of the main chain could maintain good stability though in the hot and strong polar organic solvent because of the intramolecular steric hindrance rather than the intramolecular hydrogen bonding structure.In the optimal polymerization condition above, SPA was copolymerized respectively with monomer 1, 2 and 3 in different ratios, the membrane forming ability and the CD absorption of the copolymers were both best when the ratio of the monomer and SPA in feed was 80% and 20%. It showed that the copolymers obtained by using the achiral SPA and the monomers in the condition of chiral catalysis has not only retained the polymer’s chiral helical structure, but also enhanced the membrane forming ability. The composition and the helical structure of the copolymers were respectively determined by NMR and CD. The composition of the monomer 1 and SPA in copoly1/SPA was 73% and 27%, and g value was 0.27×10-5. The composition of the monomer 2 and SPA in copoly2/SPA was 63% and 37%, and g value was 0.05×10-5. The composition of the monomer 3 and SPA in copoly3/SPA was 71% and 29%, and g value was 0.12×10-5.The membranes of the copolymers were fabricated by solvent evaporation method. The optical solution experiments of 0.8%wt DL-phenylalanine aqueous solution were carried on through the three membranes. The results indicated that the permeating quantity(PD) the permeability coefficient(α) of copoly1/SPA were 428×10-16m2/s and 1.40, respectively. The permeating quantity(PD) the permeability coefficient(α) of copoly2/SPA were 0.86×10-16m2/s and 1.28. The permeating quantity(PD) the permeability coefficient(α) of copoly3/SPA were 0.17×10-16m2/s and 1.45.