Solution and Solvent-Free Stopper Exchange Reactions for the Preparation of Pillar[5]arene-Containing [2] and [3]Rotaxanes.

Invited for the cover of this issue are the group of Iwona and Jean-François Nierengarten from the University of Strasbourg (LIMA, UMR 7042, CNRS) and collaborators from the University of Carthage and the IPHC (University of Strasbourg and CNRS, UMR 7178). The image illustrates the fast motions of a pillar[5]arene subunit along the axle of a rotaxane, reminiscent of those of a guitarist's hand along the neck allowing him to use random parts of a scale with certain sweet spots when improvising a solo. Read the full text of the article at 10.

Stepwise Functionalization of a Pillar[5]arene-Containing [2]Rotaxane with Pentafluorophenyl Ester Stoppers.

Invited for the cover of this issue are the group of Iwona and Jean-François Nierengarten from the University of Strasbourg (LIMA, UMR 7042, CNRS) and collaborators from the University of Carthage. The image depicts a sky of umbrellas floating in the air to illustrate the protective effect allowing the efficient mono-acylation of a symmetrical rotaxane building block with two pentafluorophenyl ester stoppers. Read the full text of the article at 10.

Stepwise Functionalization of a Pillar[5]arene-Containing [2]Rotaxane with Pentafluorophenyl Ester Stoppers.

Detailed investigations into the stepwise bis-functionalization of a pillar[5]arene-containing rotaxane building block have been carried out. Upon a first stopper exchange, the pillar[5]arene moiety of the mono-acylated product is preferentially located close to its reactive pentafluorophenyl ester stopper, thus limiting the accessibility to the reactive carbonyl group by the nucleophilic reagents. Selective mono-functionalization is thus very efficient.