Functional interlocked systems

Abstract

With the advent of supramolecular chemistry and later nanotechnology a great deal of research has been focused on new types of molecular structures, which are not held together by covalent bonds but by non-covalent mechanical interactions. Examples include the catenane, rotaxane, and knot interlocked structures. The design and synthesis of these architectures is an art by itself and as such is worth being reviewed. In this tutorial review we will focus, however, on the functional aspects of interlocked molecules and discuss how these can find applications, e.g. as artificial muscles, as molecular valves, as components of electronic devices, and as catalysts.

New Fluorenocrownophanes with Naphthalene Fragments: Synthesis, Structure, Properties and Interaction with Paraquat

“…The singlet form of these protons signal is, obviously, caused by the rapid rotation of the aromatic fragments of fluorenocrownophanes 2a-g on the NMR time scale. The observed spectral pattern indicates that the aromatic fragments of the crownophanes are spatially close in solutions even in the cases of 2d and 2g (according to 1 H NMR), where they are linked by pentaethylene glycol residues. Obviously, in solutions the stacking interactions take place with their intensity lowered with the increase of the ring size.…”

“…In the last decade cyclophanes and crownophanes -their polyether analogs, have been actively employed for the synthesis of supramolecular structures such as pseudorotaxanes, rotaxanes and catenanes. [1][2][3] The practical goal of these studies was to create novel compounds that are able to form strong complexes with electron-deficient substrates which can then be used to construct supramolecular and sensor systems. [4][5][6][7] The fluorene moiety, as well as its derivative fluorenone, has a large π-electron system and the removal of the carbonyl group results in increased electron density and the uniformity of its distribution.…”

Successive Translocation of the Rings in a [3]Rotaxane

“…Thanks to the advancement of synthetic methodology, many different types of molecular machines have been realized. [1][2][3][4][5] Some of these have appealing analogies in the macroscopic world, such as valves [6][7][8] and muscles. [9][10][11] Others are better viewed as information processors, [12] or function as single-molecular chemical factories.…”

Threading the Needle: Fluorescent Poly-pseudo-rotaxanes for Size-Exclusion Sensing

“…23 Systems lacking the stopper groups can have similar structures, but because they can disassemble they are referred to as pseudo-rotaxanes. 24 Polyrotaxanes, wherein a number of cyclic units are threaded onto a linear chain, have been demonstrated as effective sensing elements 25 with particular use in biotechnology due to their low cytotoxicity. 24 A combination of the molecular recognition bestowed by the host-guest polyrotaxane interactions and amplified response by exciton migration in conjugated polymers have previously been used to produce highly selective sensing schemes for Cu + ions.…”

“…24 Polyrotaxanes, wherein a number of cyclic units are threaded onto a linear chain, have been demonstrated as effective sensing elements 25 with particular use in biotechnology due to their low cytotoxicity. 24 A combination of the molecular recognition bestowed by the host-guest polyrotaxane interactions and amplified response by exciton migration in conjugated polymers have previously been used to produce highly selective sensing schemes for Cu + ions. 26,27 We report herein polyrotaxane systems based on ntype CP threaded through macrocycles of varying sizes to detect electron-rich analytes.…”