Efficient Construction of Macromolecular Loop and Study on Its Dynamics

大分子环的高效构建及其动力学研究

基本信息

批准号：
18350058
负责人：
OIKE Hideaki
金额：
$ 11.02万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Cyclic macromolecular architectures have gained increasing interests in fundamental polymer chemistry due to its closed loop topology, i.e., absence of chain ends. The lack of the excess mobility conferred by the chain ends of a cyclic polymer is believed to affect its solution and bulk properties. A typical synthetic procedure for cyclic polymers is a ring-closing reaction of an end-functional polymer precursor under dilution. However, a development of an effective polymer cyclization reaction has still been an ongoing challenge. In this study, we have synthesized cyclic and 8-shaped polystyrenes through the metathesis condensation reaction of linear and 4-armed star-shaped polystyrenes having olefinic end groups, respectively, in the presence of Grubbs catalyst. The polymer precursors were prepared by living anionic polymerization technique and were employed as a substrate of the metathesis condensation reaction. The obtained cyclic and 8-shaped polystyrenes were unequivocally characterized by means of 1H NMR, size-exclusion chromatography (SEC) and liquid chromatography at critical condition (LCCC) as well as MALDI-TOF MS techniques. Although the metathesis reaction proceeded even under the diluted condition, the reaction concentration should be below 0.2 g/L to obtain the cyclic polystyrenes in 80% selectivity, which is rather good but comparable to some conventional methods. Thus, the further investigation of an efficient cyclization system should be continued to provide an enough amount of a cyclic polymer sample for a study of polymer dynamics as well as microscopy analysis.

循环大分子结构由于其闭环拓扑（即缺乏链末端）而对基本聚合物化学的兴趣越来越不断增加。据信循环聚合物的链末端赋予的过量迁移率缺乏影响其溶液和散装特性。循环聚合物的典型合成程序是在稀释下的最终功能聚合物前体的环形反应。但是，有效的聚合物环化反应的发展仍然是一个持续的挑战。在这项研究中，我们通过在Grubbs催化剂的情况下，通过线性和4臂星形多层牙齿的元理解缩合反应合成了循环和8形的多层肾上腺。聚合物前体是通过活阴离子聚合技术制备的，并被用作分解缩合反应的底物。通过1H NMR，尺寸 - 排斥色谱法（SEC）和液态色谱法（LCCC）（LCCC）以及MALDI-TOF MS技术，明确表征获得的循环和8形的多层肾上腺。尽管即使在稀释的条件下进行的元置反应也进行，但反应浓度应低于0.2 g/l，以在80％的选择性中获得环状多层肾上腺，这相当不错，但与某些常规方法相当。因此，应继续对有效环化系统的进一步研究提供足够数量的环状聚合物样品，以研究聚合物动力学以及显微镜分析。