A photo-degradable helix: Synthesis, structure, and photolysis of optically active poly[2,7-bis(4-<i>t</i>
-butylphenyl)-9-methylfluoren-9-yl acrylate]
作者:Takeshi Sakamoto、Kento Watanabe、Yukatsu Shichibu、Katsuaki Konishi、Shin-Ichiro Sato、Tamaki Nakano
DOI:10.1002/pola.24507
日期:2011.2.15
rolidine as an optically active anionic initiator. Although the radical polymerization led to rather low‐molecular‐weight products at low yields, the anionic polymerization afforded polymers with higher molecular weights in higher yields. The poly(BBPMFA) obtained by the anionic polymerization was slightly rich in isotacticity (meso diad 57%) and showed an intense circular dichroism (CD) spectrum and
以α,α'-偶氮二异丁腈或n - Bu 3 B-air作为自由基引发剂并使用2,7-双(4-叔丁基苯基)-9-甲基氟-9-丙烯酸丙烯酸酯(BBPMFA)进行合成和聚合9-芴基锂与(S)-(+)-1-(2-吡咯烷基甲基)吡咯烷作为光学活性阴离子引发剂的配合物。尽管自由基聚合以较低的收率产生了相当低分子量的产物,但阴离子聚合却以较高的收率提供了具有较高分子量的聚合物。聚(BBPMFA通过阴离子聚合获得的)的全同立构规整度略微丰富(内消旋二单元组57%),并显示出强烈的圆二色性(CD)光谱和大的右旋性。CD光谱的强度和光学活性的大小随M n的增加而增加,表明该聚合物具有首选的螺旋构象。使用500-W Hg-Xe灯在CHCl 3溶液中辐照聚合物后,CD光谱在1 s内消失。这归因于酯键的快速光解,导致整个链的螺旋构象的损失。聚的光解产物(BBPMFA)为聚(丙烯酸)和2,7-双(4-吨丁基苯基)-9-