侧基对N-炔丙基酰胺螺旋共聚物光学活性的影响

设计并合成了5个系列的带有不同侧基的手性-非手性N-炔丙基酰胺共聚物,以铑有机配合物为催化剂对单体实施聚合反应得到高产率(>95%)的共聚物,聚合物具有高立构规整性(cis-含量高于94%).利用圆二色(CD)及紫外-可见吸收(UV-Vis)光谱技术对共聚物的二级结构及光学活性进行了表征,当非手性单体的酰胺侧基体积适中时,共聚物具有较高的光学活性,部分共聚物的光学活性甚至高于纯手性聚合物.表明通过选择合适的手性-非手性共聚单体及单体配比,可获得具有高光学活性的螺旋聚合物.

EFFECTS OF PENDENT GROUPS ON OPTICAL ACTIVITY OF HELICAL N-PROPARGYLAMIDE COPOLYMERS

5 Series of chiral-achiral N-propargylamide copolymers were synthesized,providing copolymers with moderate number-average molecular weights in high yields.For the copolymers from the achiral monomers with appropriate bulky pendent groups,the moderate steric hindrance between the pendent groups enabled the copolymer main chains to adopt helices preferring the same handed screw sense taken by the chiral units;the corresponding copolymers exhibited higher CD signal intensity even when compared with the pure chiral polymer.However,for the achiral co-monomers with too small or too large pendent groups,they were unfavorable for the resulting copolymers to prefer the helical handedness adopted by the chiral units,leading to low CD signal intensity.These findings would be helpful for us to design and synthesize novel helical N-propargylamide polyand copolymers with high optical activity.