not. The chiral amino acid units in the side chains of Poly(IV3,4) induced the main chain to form the helical conformation. In addition, owing to the large steric repulsion and π-π interaction between the bulky fluorene groups, Poly(IV3,4) showed good helical stability at various temperatures (− 10–60 °C) and in strong polar solvents. Especially, the CD intensity of Poly(IV3) was enhanced with increasing
一系列带有
芴侧基的新型取代
乙炔单体(C 13 H 9 COCH 2 CH 2 CO-R-CH 2 C CH,R = NH(IV 1),R = O(IV 2),R = NHCH(CH 3)CONH(IV 3),R = NHCH(CH 3)COO(IV 4))已合成,随后与[Rh(nbd)Cl] 2作为催化剂聚合,得到相应的聚
乙炔(Poly(IV 1 – 4))。在11 H NMR谱表明,所有获得的聚
乙炔具有高的顺式-立体有规结构。CD(圆二色性)和UV-vis光谱的结果表明,聚(IV 3,4)采取了紧螺旋结构,而聚(IV 1,2)没有。在侧链中的手性
氨基酸单元的聚(IV 3,4中感应的主链),以形成螺旋构象。此外,由于大的斥力和庞大的
芴基之间的π-π相互作用,聚(IV 3,4)在各种温度(− 10–60°C)和强极性溶剂中显示出良好的螺旋稳定性。特别地,随着溶剂极性的增加,聚( IV 3)的CD强度增加。此外,聚(