Department of Chemistry, Osaka Dental University, Hirakata, Osaka, 5731121, Japan.
Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, Osaka, 5648680, Japan.
Chemistry. 2021 Jan 26;27(6):1966-1969. doi: 10.1002/chem.202004505. Epub 2020 Dec 9.
A [c2]daisy chain rotaxane with two diarylacetylene cores was efficiently synthesized in 53 % yield by capping a C -symmetric pseudo[2]rotaxane composed of two diarylacetylene-substituted permethylated α-cyclodextrins (PM α-CDs) with aniline stoppers. The maximum absorption wavelength of the [c2]daisy chain rotaxane remained almost unchanged in various solvents, unlike that of the stoppered monomer, indicating that the two independent diarylacetylene cores were insulated from the external environment by the PM α-CDs. Furthermore, the [c2]daisy chain rotaxane exhibited fluorescence emission derived from both diarylacetylene monomers and the excimer, which implies that the [c2]daisy chain structure can undergo contraction and extension. This is the first demonstration of a system in which excimer formation between two π-conjugated molecules within an isolated space can be controlled by the unique motion of a [c2]daisy chain rotaxane.
一种具有两个二芳基乙炔核心的[C2]雏菊链轮烷以 53%的产率高效合成，通过用苯胺封端剂封端由两个二芳基乙炔取代的全甲基化α-环糊精（PM α-CDs）组成的 C-对称拟[2]轮烷来实现。[C2]雏菊链轮烷的最大吸收波长在各种溶剂中几乎保持不变，与封端单体不同，这表明两个独立的二芳基乙炔核心被 PM α-CDs 与外部环境隔离。此外，[C2]雏菊链轮烷表现出源于两个二芳基乙炔单体和激基复合物的荧光发射，这意味着[C2]雏菊链结构可以经历收缩和延伸。这是首例证明在隔离空间内两个π共轭分子之间的激基复合物形成可以通过[C2]雏菊链轮烷的独特运动来控制的系统。
