The Slipping Approach to Self-Assembling [<i>n</i>]Rotaxanes
作者:Masumi Asakawa、Peter R. Ashton、Roberto Ballardini、Vincenzo Balzani、Martin Bělohradský、Maria Teresa Gandolfi、Oldrich Kocian、Luca Prodi、Françisco M. Raymo、J. Fraser Stoddart、Margherita Venturi
DOI:10.1021/ja961817o
日期:1997.1.1
A synthetic approach-namely slippage-to self-assembling [n]rotaxanes incorporating pi-electron deficient bipyridinium-based dumbbell-shaped components and pi-electron-rich hydroquinone- and/or dioxynaphthalene-based macrocyclic polyether components has been developed. The kinetics of rotaxane formation by the slipping procedure were investigated by absorption UV-visible and H-1-NMR spectroscopies in a range of temperatures and solvents, varying systematically the size of both the stoppers and the macrocyclic components. As expected, the rate constants for these processes are affected by the size complementarity between macrocycles and stoppers. Furthermore, the enthalpic and entropic contributions to the free energies of activation associated with the slippage and the effect of solvent polarity upon the outcome of these processes have been evaluated. In addition, the spectroscopic and electrochemical properties of some of the rotaxanes are presented and discussed with reference to the properties of their chromophoric and electroactive units.
Recognition of Bipyridinium-Based Derivatives by Hydroquinone- and/or Dioxynaphthalene-Based Macrocyclic Polyethers: From Inclusion Complexes to the Self-Assembly of [2]Catenanes
作者:Masumi Asakawa、Peter R. Ashton、Sue E. Boyd、Christopher L. Brown、Richard E. Gillard、Oldrich Kocian、Françisco M. Raymo、J. Fraser Stoddart、Malcolm S. Tolley、Andrew J. P. White、David J. Williams
DOI:10.1021/jo961025c
日期:1997.1.1
extended to the self-assembly of [2]catenanes incorporating the bipyridinium-based cyclophane, cyclobis(paraquat-p-phenylene), and the macrocyclic polyethers incorporating dioxybenzene and -naphthalene units. The efficiencies of these self-assembly processes were found to depend upon the stereoelectronic features of the pi-electron-rich macrocycles-namely, the nature and the substitution pattern of the