Macrocyclic ligands, complexation soft metal ions

Compartmental ligands (16) provide extensive opportunities for multiple metal ion complexation. An example of a mixed donor ligand incorporating different metal ions is the macrocyclic trinucleating hgand (63), which is capable of complexing two soft donor metal centers in addition to a hard alkali or alkaline earth metal. ... 

Thioether analogs of the crowns have been known since the 1930s,103 but metal ion complexes of these ligands have not been investigated with the intensity found for the crowns and polyaza macrocycles. As anticipated from the soft nature of the heteroatom, the sulfur macrocycles show a preference to bind transition metals rather than alkali and alkaline earth ions. Studies have... 

The relative quality of structure calculations by different computational techniques was assessed using the small macrocycle 1,4,7-trithiacyclononane 9S3 (Fig. la.b)—a ligand showing a complexation preference for soft transition and post-transition metal ions. Given in Fig. 2 is a compilation of the deviations (represented by... 

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