Macrobicyclic cryptate cation selectivity

Macrobicyclic cryptate cation selectivity, 27 16-17 complex stability, 27 14-15 kinetic studies, 27 13-14... 

Indeed, macrobicyclic ligands such as 7-9 form cryptates [Mn+ c cryptand], 10, by inclusion of a metal cation inside the molecule [1.26, 1.27, 2.17, 2.24-2.26]. The optimal cryptates of AC and AEC have stabilities several orders of magnitude higher than those of either the natural or synthetic macrocyclic ligands. They show pronounced selectivity as a function of the size complementarity between the cation... 

A cryptate effect is observed for anion complexes as is the case for cation complexes (Section 2.3). In general, an increase in cyclic order from acyclic to macro-cyclic to macrobicyclic significantly increases the stability and selectivity of the anion complexes formed by polyammonium ligands. 

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