Host–guest interactions template: the synthesis of a [3]catenane
作者:Amy L. Hubbard、Gregory J. E. Davidson、Roopa H. Patel、James A. Wisner、Stephen J. Loeb
DOI:10.1039/b312449e
日期:——
Formation of a [3]catenane containing dibenzo-24-crown ether wheels and a large dipyridiniumethane ring is templated by formation of a host-guest adduct between the [3]catenane and the external crown ether.
A [2]Rotaxane Flip Switch Driven by Coordination Geometry
作者:Gregory J. E. Davidson、Sapna Sharma、Stephen J. Loeb
DOI:10.1002/anie.201001486
日期:——
The carrot is better than the stick! Changes in the metal coordination geometry of the capping group in a [2]rotaxane ligand results in molecular switching by reorienting a trapped macrocyclic component (see picture). Switching was successfully initiated when the metal coordination site was made more attractive (square planar), but not when the metal coordination site was made less attractive (octahedral)
[2]Rotaxanes containing pyridinium–phosphonium axles and 24-crown-8 ether wheels
作者:Norma Georges、Stephen J. Loeb、Jorge Tiburcio、James A. Wisner
DOI:10.1039/b407653b
日期:——
A triethylphosphonium group attached to a pyridinium ethane moiety can be used as an axle for the self-assembly of [2]pseudorotaxanes and [2]rotaxanes. Although [2]pseudorotaxane formation is limited due to the bulk of the PR4+ group, [2]rotaxanes can be formed utilising 24-crown-8 ether, benzo-24-crown-8 ether and naphtho-24-crown-8 ether. The synthesis of these [2]rotaxanes and the X-ray structure of the [2]rotaxane containing a 24-crown-8 ether wheel are described. When the crown ether contains an aromatic group two possible conformational isomers exist; these are identified at low temperature by 1H and 31P NMR spectroscopy.