title: A light-powered stretch-contraction supramolecular system based on cobalt coordinated [1]rotaxane.
abstract: A mechanically switchable bistable [1]rotaxane, constituted of azobenzene modified cyclodextrins (CyDs) and a Schiff base bridged by a metallosalen unit, was designed and synthesized. (1)H NOESY NMR and ICD spectra were investigated to characterize the movement process of this stretch-contraction supramolecular system. The geometries of [1]rotaxane before and after irradiation by UV light were optimized and calculated. Coordinated with cobalt(III) ion, the rotaxane becomes more rigid and linear, which is seen from the more obvious signals in the induced circular dichroism (ICD) and (1)H NMR spectra. This type of light-powered [1]rotaxane has favourable repeatability and exhibits a novel approach to elaborate the transformation of a light-driven molecular machine.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science & Technology, Meilong Road 130, Shanghai 200237, P. R. China.
authors.forename: Chao
authors.initials: C
authors.lastname: Gao
authors.forename: Xiang
authors.initials: X
authors.lastname: Ma
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.forename: Qiaochun
authors.initials: Q
authors.lastname: Wang
authors.forename: Dahui
authors.initials: D
authors.lastname: Qu
authors.forename: He
authors.initials: H
authors.lastname: Tian
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D007536:Isomerism; D008958:Models, Molecular; D015394:Molecular Structure; D043862:Rotaxanes / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D043862:Rotaxanes; D003035:Cobalt