title: Two switchable star-shaped [1](n)rotaxanes with different multibranched cores.
abstract: Two novel star-shaped [1](n)rotaxanes with three and four identical [1]rotaxane arms but different multibranched cores were designed, synthesized, and well-characterized. In the two systems, external base-acid stimuli result in the uniform relative mechanical movement of the macrocyclic rings and threads of their [1]rotaxane arms. The energy-minimized structures of the two rotaxanes in different states were obtained using molecular dynamics simulations in acetone solution, suggesting the construction of more sophisticated molecular machines mimicking the extension and contraction motions.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science & Technology , Shanghai 200237, P. R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Hans
authors.initials: H
authors.lastname: Ågren
authors.forename: Da-Hui
authors.initials: DH
authors.lastname: Qu