title: Separated and aligned molecular fibres in solid state self-assemblies of cyclodextrin [2]rotaxanes.
abstract: The conformations of two [2]rotaxanes, each comprising alpha-cyclodextrin as the rotor, a stilbene as the axle and 2,4,6-trinitrophenyl substituents as the capping groups, have been examined in solution and in the solid state, using (1)H NMR spectroscopy and X-ray crystallography, respectively. In solution, introducing substituents onto the stilbene prevents the cyclodextrin from being localized over one end of the axle. Instead the cyclodextrin moves back and forth along the substituted stilbene. In the solid state, the axles of the rotaxanes form extended molecular fibres that are separated from each other and aligned along a single axis. The molecular fibres are strikingly similar to those formed by the axle component of one of the rotaxanes in the absence of the cyclodextrin, but in the latter case they are neither separated nor all aligned.
authors.affiliation: Research School of Chemistry, Institute of Advanced Studies, Australian National University, Canberra ACT 0200, Australia.
authors.forename: Hideki
authors.initials: H
authors.lastname: Onagi
authors.forename: Benedetta
authors.initials: B
authors.lastname: Carrozzini
authors.forename: Giovanni L
authors.initials: GL
authors.lastname: Cascarano
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Easton
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Edwards
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Lincoln
authors.forename: A David
authors.initials: AD
authors.lastname: Rae
mesh_terms: D018360:Crystallography, X-Ray; D003505:Cyclodextrins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D036103:Nanotechnology; D010851:Picrates / Q000737:chemistry; D043862:Rotaxanes / Q000737:chemistry*; D012996:Solutions; D013267:Stilbenes / Q000737:chemistry; D047391:alpha-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D010851:Picrates; D043862:Rotaxanes; D012996:Solutions; D013267:Stilbenes; D047391:alpha-Cyclodextrins; C005858:picric acid; C032613:alpha-cyclodextrin