This communication reports a novel sandwich-like rotaxane shuttle, which exhibits a unique mode of potential-controlled behaviour. Two dynamic processes occur simultaneously - conformational "unfolding" of the DADA stack accompanies translocation of the ring over the rotaxane's axle.

Thin films of fumaramide [2]rotaxane, a mechanically interlocked molecule composed of a macrocycle and a thread in a "bead and thread" configuration, were prepared by vapor deposition on both Ag(111) and Au(111) substrates. X-ray photoelectron spectroscopy (XPS) and high-resolution electron-energy-loss spectroscopy were used to characterize monolayer and bulklike multilayer films. XPS determina...

A [3]rotaxane 1 involving two naphtho-21-crown-7 (N21C7) rings and a dumbbell-shaped component 4 was synthesized. The dumbbell-shape molecule 4 contains one viologen nucleus, two secondary alkyl ammonium sites and two phenyl stoppers. After threading the N21C7 ring with the thread-like ammonium guest 3, the copper(I)-catalyzed Huisgen alkyne-azide 1,3-dipolar cycloaddition (CuAAC ‘‘click’’ reac...

Results of gel-phase proton high resolution magic angle spinning (HR MAS) NMR spectroscopy are described for a systematic study of the reversible, thermodynamically-controlled assembly of surface-attached neutral rotaxanes and pseudorotaxanes based on a three-component system consisting of a naphthodiimide thread unit, a naphthalene crown shuttle, and metalloporphyrin stoppers. Further to the p...

Copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition between terminal alkynes and azides – also known as the copper (Cu)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) – has been used in the syntheses of molecular compounds with diverse structures and functions, owing to its functional group tolerance, facile execution, and mild reaction conditions under which it can be promoted. Recently, rotax...

The structural reorganization of nanoscale DNA architectures is a fundamental aspect in dynamic DNA nanotechnology. Commonly, DNA nanoarchitectures are reorganized by means of toehold-expanded DNA sequences in a strand exchange process. Here we describe an unprecedented, toehold-free switching process that relies on pseudo-complementary peptide nucleic acid (pcPNA) by using a mechanism that inv...

An acid-base switchable molecular shuttle based on a [2]rotaxane, incorporating stable radical units in both the ring and dumbbell components, is reported. The [2]rotaxane comprises a dibenzo[24]crown-8 ring (DB24C8) interlocked with a dumbbell component that possesses a dialkylammonium (NH2 (+)) and a 4,4'-bipyridinium (BPY(2+)) recognition site. Deprotonation of the rotaxane NH2 (+) centers e...

This paper describes novel host-guest systems comprising viologen cations (guests) and the derivatives of bis-para-phenylene-34-crown-10 (hosts) with anionic groups COO(-) or SO(3)(-). The structure of the resulting charge-compensated host-guest complexes, their association constants and their electrochemical behaviour have been studied. In the solid state, the viologen cations thread the negat...

We report the synthesis and photophysical investigation of a series of rotaxanes in which the physical confinement of the donor and acceptor (DA) pair leads, in some cases, to emissive exciplexes. As a comparison, we examined the photoinduced charge-transfer processes in the same DA mixtures under intermolecular conditions. The interlocked configuration of the rotaxane facilitates pi orbital ov...