Mechanically interlocked materials. Rotaxanes and catenanes beyond the small molecule.

A mechanical bond presents a combination of the best features of covalent and supramolecular chemistries (stability and structural integrity), plus a unique dynamic nature, that makes it a very interesting tool for materials chemistry. Here, we overview the chemistry of the mechanical bond applied to polymers, metal-organic frameworks (MOFs) and carbon nanotubes. We first describe synthetic strategies towards polycatenanes and polyrotaxanes, and highlight their potential impact in polymer chemistry, exemplified by their use to make stimuli-responsive gels and as binders in battery electrodes. We continue by showing how to include mechanically interlocked components in MOFs, and analyse the distinctive dynamic properties of the final constructs. Finally, we describe the strategies towards mechanically interlocked derivatives of single-walled carbon nanotubes (SWNTs), and discuss the potential of the mechanical bond to tackle some of the classic problems of SWNT chemistry.