A [2]rotaxane has been constructed from a di-pyrene appended pillar[5]arene wheel, a pyridinium axle, and a perylene stopper. It shows efficient Förster resonance energy transfer from pyrene to perylene by formation of a mechanically interlocked [2]rotaxane.

The preparation of a novel anthracene-containing dynamic [2]rotaxane by a templating self-assembly process between a diamine and a dialdehyde to form a [24]crown-8 macrocyclic diimine, in the presence of a dumbbell containing a secondary dialkylammonium ion center as the template, which has been exploited for its sensing properties. By appealing to the ability of the anthracene ring system--one...

We have used single-crystal X-ray diffraction and time-resolved UV-NIR-IR absorption spectroscopy to gain insights into the structures and excited-state dynamics of a rotaxane consisting of a hexayne chain threaded through a phenanthroline macrocycle and a family of related compounds, including the rhenium(I) chlorocarbonyl complex of this rotaxane. The hexayne unit in the rhenium-rotaxane is s...

A mechanically interlocked squaraine rotaxane is comprised of a deep-red fluorescent squaraine dye inside a tetralactam macrocycle. NMR studies show that Cl(-) binding to the rotaxane induces macrocycle translocation away from the central squaraine station, a process that is completely reversed when the Cl(-) is removed from the solution. Steady-state fluorescence and excited-state lifetime mea...

The mechanical interlocking of molecular components can lead to the appearance novel and unconventional properties processes, with potential relevance for applications in nanoscience, sensing, catalysis, materials science. We describe a [3]rotaxane which number recognition sites available on axle component be changed by acid-base inputs, encompassing cases this is larger, equal to, or smaller t...

The effect of varying the size of the macrocycle component on the formation of anion templated imidazolium interpenetrated assemblies is investigated. Two different approaches to reducing the macrocycle size are undertaken and the stabilities of the resulting pseudorotaxanes incorporating substituted imidazolium threading components studied using (1)H NMR spectroscopy. Novel imidazolium axle co...

A systematic comparison of empty tetralactam macrocycles containing 1,3-benzenedicarboxamide, 2,6-pyridinedicarboxamide, and 1,3-adamantanedicarboxamide bridging units finds that macrocycles with adamantyl bridging units exhibit weaker non-covalent affinity for an encapsulated guest. In the case of interlocked squaraine rotaxanes with macrocycles containing phenylene sidewalls, the structural c...

We examine a rod piston-rotaxane system, where the positions of several mobile rings on the axle are controlled by an external force acting on one of the rings. This allows us to access the translational entropy of the rings. For a simple rotaxane molecule with an axle that has uniform ring-axle interactions along its length, the molecule behaves like a miniature piston filled with a one-dimens...

It was demonstrated that various threaded structures could be constructed by employing different esters as end groups based on the benzo-21-crown-7/secondary ammonium salt recognition motif. The chemical structures of all synthesized compounds were confirmed by (1)H and (13)C NMR spectroscopy as well as mass spectrometry. Single crystal X-ray analysis revealed that all compounds are threaded st...