Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites in the Axis

A new example of a linear [5]rotaxane has been synthesized by using the traditional "gathering-and-threading" approach but based on an unusual axle incorporating a symmetrical bis(bidentate) chelating fragment built on a 4,7-phenanthroline core. The stoppering reaction is particularly noteworthy since, instead of using a trivial bulky stopper as precursor to the blocking group, two semistoppered copper-complexed [2]pseudorotaxanes (namely [2]semirotaxanes) are used, which leads to the desired [5]rotaxane in good yield. The efficiency of the method relies on the use of "click" chemistry, with its very mild conditions, and on the protection by a transition-metal (copper(I)) of the various coo…

Frontispiece: Positive Allosteric Control of Guests Encapsulation by Metal Binding to Covalent Porphyrin Cages

Positive Allosteric Control of Guests Encapsulation by Metal Binding to Covalent Porphyrin Cages

The allosteric control of the receptor properties of two flexible covalent cages is reported. These receptors consist of two zinc(II) porphyrins connected by four linkers of two different sizes, each incorporating two 1,2,3‐triazolyl ligands. Silver(I) ions act as effectors, responsible for an on/off encapsulation mechanism of neutral guest molecules. Binding silver(I) ions to the triazoles opens the cages and triggers the coordination of pyrazine or the encapsulation of N,N′‐dibutyl‐1,4,5,8‐naphthalene diimide. The X‐ray structure of the silver(I)‐complexed receptor with short connectors is reported, revealing the hollow structure with a cavity well‐defined by two eclipsed porphyrins. Rath…

CCDC 1844318: Experimental Crystal Structure Determination

Related Article: Ryan Djemili, Lucas Kocher, Stéphanie Durot, Anssi Peuronen, Kari Rissanen, Valérie Heitz|2018|Chem.-Eur.J.|||doi:10.1002/chem.201805498

CCDC 1844317: Experimental Crystal Structure Determination

Related Article: Ryan Djemili, Lucas Kocher, Stéphanie Durot, Anssi Peuronen, Kari Rissanen, Valérie Heitz|2018|Chem.-Eur.J.|||doi:10.1002/chem.201805498