Separated and aligned molecular fibres in solid state self-assemblies of cyclodextrin [2]rotaxanes.
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.
Onagi
Hideki
H
Research School of Chemistry, Institute of Advanced Studies, Australian National University, Canberra ACT 0200, Australia.
Carrozzini
Benedetta
B
Cascarano
Giovanni L
GL
Easton
Christopher J
CJ
Edwards
Alison J
AJ
Lincoln
Stephen F
SF
Rae
A David
AD
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
D003505:Cyclodextrins; D010851:Picrates; D043862:Rotaxanes; D012996:Solutions; D013267:Stilbenes; D047391:alpha-Cyclodextrins; C005858:picric acid; C032613:alpha-cyclodextrin