中文摘要：

以铑金属络合物为催化剂，手性N-炔丙基酰胺单体均聚反应，采用逐步沉淀法将得到的聚合物分级，用GPC法确定各级聚合物的分子量及其分布，并用圆二色（CD）和紫外-可见吸收（uV-Vis）光谱技术及旋光仪对各级聚合物的二级结构及光学活性进行表征。结果表明，分子量对螺旋聚合物的光学活性有重要影响，当分子量较低时（平均聚合度DP为5），聚合物不能形成稳定的螺旋结构；在DP为11—85的范围内，聚合物CD信号的强度和比旋光度随着聚合度的增加而显著提高；但当聚合度进一步增大时（DP为105～166），CD信号的强度和比旋光度变化不再明显。

英文摘要：

A chiral N-propargylamide monomer was polymerized with a Rh-catalyst and the resulting polymers were fractionated by the step-precipitation method. The average molecular weights and the molecular weight distributions of the various fractions were determined by GPC. The secondary structures and optical activities of the resulting pol- ymers were examined by UV-Vis and CD spectroscopies. The results showed that the optical activity was highly de- pendent on the molecular weight of the polymer. When the polymerization degree （DP） was low （DP was 5）, the oligomer could not adopt a stable helical conformation. With increasing polymerization degree from 11 to 85, both the intensity of the CD signal and the specific rotation rose rapidly. A further increase in DP, in the range 105 - 166 gave rise to little change in either the intensity of the CD effect or the specific rotation.