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Construction and Function of Supramolecular polvmers

超分子聚合物的结构与功能

基本信息

批准号：
10450350
负责人：
UENO Akihiko
金额：
$ 8.64万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

The main object of this study is construction of polyrotaxanes composed of cyclodextrin (CD) and modified CD as a novel copolymers, in which monomer units are connected together not by covalent bond but by supramolecular interaction. From this viewpoint, we prepared a series of polyrotaxanes, which have α-CD and naphthtalene-modified α-CD (NpCD) as monomer units and a poly (ethylene glycol) as a threading chain. The ratios of the NpCD unit in the polyrotaxanes are 20%, 60%, and 100 % when both ends of poly (ethylene glycol) have anthracene units as stoppers. We examined energy transfer from naphthalene units to anthracene units in the systems, in which naphthalene units may be expected to act as antenna units which absorb light. Light harvesting ability of the systems increased but energy transfer efficiency from the naphthalene units to anthracene ones decreased with increasing content of naphthalene unit in the polyrotaxane series. This system also revealed that fluorescence anisotropy decreases with increasing content of NpCD in the polyrotaxanes, informing that energy migration occurs and energy tends to be lost during the randomly occurring energy transfer. We also constructed another type of polyrotaxanes, in which trinitrophenyl units exist at both ends. We observed quenching of the naphthalene fluorescence in various solvent systems with different polarities and found that highly efficient energy transfer is attained in the solvent system of low polarity and antenna effect becomes remarkable with increasing content of naphthalene unit in the polyrotaxanes.

本研究的主要目的是构建一种由环糊精（CD）和改性CD组成的新型共聚物聚轮烷，其单体单元不是通过共价键连接，而是通过超分子相互作用连接。从这个角度出发，我们制备了一系列以α-CD和萘修饰α-CD （NpCD）为单体单元，以聚乙二醇为线链的聚轮烷。当聚乙二醇的两端都有蒽单元作为塞时，NpCD单元在聚轮烷中的比例分别为20%、60%和100%。我们研究了系统中从萘单位到蒽单位的能量转移，其中萘单位可能作为吸收光的天线单位。随着聚轮烷系列中萘单元含量的增加，体系的光收集能力提高，但萘单元向蒽单元的能量传递效率降低。该系统还揭示了荧光各向异性随聚轮烷中NpCD含量的增加而降低，这表明在随机发生的能量转移过程中发生了能量迁移和能量损失。我们还构造了另一种类型的聚轮烷，其中三硝基苯单元存在于两端。我们观察了萘荧光在不同极性溶剂体系中的猝灭现象，发现在低极性溶剂体系中能获得高效的能量传递，并且随着聚轮烷中萘单元含量的增加，天线效应显著。