Cyclodextrin Rotaxane with Switchable Pirouetting

Abstract

A [1]rotaxane with two threaded α-cyclodextrin (α-CD) wheels was synthesized in 92% yield using a one-pot process at room temperature that employed spontaneous α-CD threading onto a twelve-carbon alkyl chain in water, followed by an oxime condensation reaction that attached two boronic acid-containing stopper groups. Rapid pirouetting of the threaded α-CD wheels around the encapsulated dumbbell was switched “ON” or “OFF” by the presence of chemical additives that controlled boronate ester bond formation between the interlocked components.

Dynamic [1]rotaxanes via a reversible covalent bond and host–guest anion recognition

“…Other interesting functions include sensing, 16 stabilization of reactive species (e.g. radicals 17 and metal complexes 18 ) by encapsulation, switchable pirouetting, 19 forming responsive supramolecular vesicles for drug delivery, 20 and multifunctional systems realizing logic operations. [21][22][23] A vast majority of (pseudo) [1]rotaxanes exploit host-guest chemistry of macrocycles for their formation.…”

Suit[4]ane

“…The molecular topologies and architectures associated with mechanical bonds dictate the nature of the relative motions of their components. For example, rotaxanes and catenanes, the archetypal MIMs, exhibit motions such as translocation, − circumrotation, pirouetting, and rocking . These motions are key elements when it comes to the design and operation of molecular machines , such as switches, , rotors, − motors, and pumps. − …”

Stoichiometry-Controlled Chirality Induced by Co-assembly of Tetraphenylethylene Derivative, γ-CD, and Water-Soluble Pillar[5]arene

“…The advance of self-assembly chemistry creates versatile architectures in arenas of chemistry, materials, and biomedical science. − By controlling the external conditions, the formation of self-assemblies could be switched on and off. − Furthermore, functions and properties of these self-assemblies are intimately related to their topological morphologies. As the signature of life, chirality plays a vital role in chiral recognition, chiral separation, and especially in the various living systems. − The formation of the supramolecular chirality from self-assemblies is a very unique and attractive phenomenon in life, as represented by the right-handed a -helix of proteins and the right-handed double helix of DNA. − It is an important pathway to manipulate supramolecular chirality by fine-tuning morphology of molecular self-assemblies.…”