Abstract: A variety of artificial molecular devices and machines have been constructed based on supramolecular systems which including the rotaxanes, catenanes and pseudorotaxanes containing the 24-crown-8 ring and relative positive organic guests. The chemical and physical methods which can be used to operate the molecular devices and machines by controlling the input of 1)acid-base 2)competitive agents 4)anions 3)light 4)heat 5)red/ox potential 6)protecting group 7)solvents were discussed. The switchable strategy based on motion of threading/dethreading in pseudorotaxane can be used to perform a great deal of functions. In rotaxane and catenane systems, the function of molecular machines can be performed through varying the relative positions and orientations of the components to realize shuttling and circumrotation motions utilizing the inputting energy.

Key words: Molecular device, Molecular machine, 24-crown-8