We describe a new concept for rotaxane synthesis through intramolecular slippage using π‐conjugated molecules as rigid axles linked with organic soluble and flexible permethylated α‐cyclodextrins (PM α‐CDs) as macrocycles. Through hydrophilic–hydrophobic interactions and flipping of PM α‐CDs, successful quantitative conversion into rotaxanes was achieved without covalent bond formation. The rotaxanes
我们描述了一种新的概念,即通过使用π共轭分子作为刚性轴与有机可溶性和柔性全甲基化α-环糊精(PMα-CDs)作为大环连接的分子内滑动来合成轮烷的新概念。通过亲水-疏水相互作用和PMα-CD的翻转,可以成功地定量转化为轮烷,而不会形成共价键。轮烷具有很高的脱线活化屏障,因此即使在不利于维持轮烷结构的条件下,它们也被动力学分离和衍生化。1个1 H NMR光谱实验清楚地表明,通过刚性轴连接的大环的受限运动使得可以通过调节前体结构中刚性轴的长度而不是塞子单元的空间体积来控制动力学稳定性。
Highly organic soluble [1]–[1]rotaxane also known as linked [3]rotaxane was synthesized by intramolecular self-inclusion of a modified permethylated α-cyclodextrin (PM α-CD) to form a pseudo[1]rotaxane followed by dimerization. The NMR spectroscopy of thus formed rotaxane suggests that the diphenylacetylene units are fully encapsulated by the PM α-CDs. The Stern–Volmer analysis of fluorescence quenching using a viologen analogue shows that the PM α-CDs inhibits electron transfer efficiently suggesting a high coverage ratio of the π-conjugated axle with the PM α-CDs.
Synthesis of an Organic-soluble π-Conjugated [1]Rotaxane
作者:Susumu Tsuda、Jun Terao、Nobuaki Kambe
DOI:10.1246/cl.2009.76
日期:2009.1.5
An organic-soluble π-conjugated [1]rotaxane has been synthesized by intramolecular self-inclusion of a lipophilic permethylated α-cyclodextrin bearing a rigid π-conjugated system as a guest moiety. End-capping has been achieved successfully by connecting an aniline moiety without using bulky stoppers. The structure of the [1]rotaxane was determined by 2D NMR spectroscopy.
Linked symmetric [3]rotaxanes consisting of an oligomeric phenylene–ethynylene (OPE) unit as a π-conjugated guest and two molecules of organic soluble permethylated α-cyclodextrins (PM α-CDs) as macrocyclic hosts have been synthesized by intramolecular self-inclusion of an OPE guest moiety carrying PM α-CDs followed by double cross-coupling reaction with 1,4-diiodobenzene under the Sonogashira coupling conditions. The structure of thus formed rotaxane was determined by MALDI-TOF mass spectrum and two-dimensional NMR spectroscopy.