189118-52-3Relevant academic research and scientific papers
Translational Isomerism in Some Two- and Three-Station [2]Rotaxanes
Amabilino, David B.,Ashton, Peter R.,Boyd, Sue E.,Gomez-Lopez, Marcos,Hayes, Wayne,Stoddart, J. Fraser
, p. 3062 - 3075 (1997)
The template-directed syntheses of three [2]rotaxanes are described. They all have dumbbell , components, with both hydroquinone and resorcinol rings inserted into polyether chains terminated by tetraarylmethane stoppers, that become encircled during the key self-assembly processes by the tetracationic cyclophane, cyclobis(paraquat-p-phenylene), with its two π-electron deficient bipyridinium units. It has been demonstrated by low-temperature 1H NMR spectroscopy that the π-electron deficient tetracationic cyclophane has a remarkably high preference to reside around the hydroquinone ring in these molecular shuttles. This observation illustrates how a very small constitutional difference-hydroquinone versus resorcinol recognition sites-can lead to the overwhelming preference for one translational isomer over another in this particular range of [2]rotaxanes.
