Cyclodextrin‐Based [c2]Daisy Chain Rotaxane Insulating Two Diarylacetylene Cores

Abstract

A [c2]daisy chain rotaxane with two diarylacetylene cores was efficiently synthesized in 53 % yield by capping a C2‐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.

DNA-Based Daisy Chain Rotaxane Nanocomposite Hydrogels as Dual-Programmable Dynamic Scaffolds for Stem Cell Adhesion

“…DCRs are series of special interlocked structures containing two pairs of thread-macrocycle structures, which are then cross-threaded into dimers along two axles. − Two stoppers are introduced to prevent the dethreading. DCRs can perform muscle-like extension/contraction movements by sliding along two parallel interlocked axles.…”

Daisy chain architectures: from discrete molecular entities to polymer materials

“…A few years later, the group of Nishiyama reported the formation of [ c 2]daisy chain rotaxanes from a permethylated α-cyclodextrin (PM α-CD) monomer in aqueous solution (entry 2, Table 1). 30 The monomer which consists of a diarylacetylene axle covalently connected to a PM α-CD was synthesized in five steps from α-CD. In a 2 : 1 mixture of methanol and water, formation of a pseudo-[ c 2]daisy chain occurred which could be capped by an amidation reaction between the carboxylic acid located at the end of the axle and a bulky aniline.…”