Mechanically interlocked rotaxane molecular shuttles occupy an important position in the area of molecular machines chemistry, and is a good "bottom-up" strategy for the self-assembly of new materials at the molecular level. In such shuttles, a macrocycle can be translocated between different "stations" or recognition sites of the thread in response to an external stimulus. The alternation of relative positions of the interlocked components can result in varying physical or chemical properties. The alternative variation of properties constitutes a basic kind of mechanical switch, capable of performing particular functions. The above-mentioned molecular shuttles have attracted wide attentions of supramolecular chemists due to their potential applications as molecular devices for switches, information storage and processing, and so on. In this paper, the new research progress in chemically driven [2]rotaxane molecular shuttles on syntheses and applications in recent years is reviewed, based on the driving forces (i.e. external stimuli) such as acid/base driven, ion coordination interaction driven, hydrophobic interaction driven induced by the change of solvent polarity. And the other forces driven [2]rotaxane molecular shuttles are also summarized such as thermodynamical entropy, the size of the decorated groups in the interlocked system, chemical oxidants or reductants, electrochemical redox related to electron gain or loss, photoisomerization of the azobenzene unit between trans and cis isomer induced by UV or visible light irradiation, and so on. Furthermore, the future development of such [2]rotaxane molecular shuttles is prospected.

Contents
1 Introduction
2 Chemically driven [2]rotaxane molecular shuttles
2.1 Acid/base driven [2]rotaxane molecular shuttles
2.2 Ion coordination interaction driven [2]rotaxane molecular shuttles
2.3 Hydrophobic interaction driven induced by the change of solvent polarity [2]rotaxane molecular shuttles
2.4 Other forces driven [2]rotaxane molecular shuttles
3 Conclusion and outlook