Organometallic complexes of crown ethers, cryptands and related receptors

1 Organometallic complexes of crown ethers, cryptands and related receptors 

The crown ethers and related macrocyclic molecules can act as hosts for organometallic guests and form complexes similar to those of naked metal ions. The situation can, however, be more complex because the crown ethers can behave both as endo and exo receptors toward organometallic coordination centers. In the latter circumstance the crown ether acts as a simple multidentate ligand and molecular recognition is not necessarily part of the process. 

Macrocyclic complexes of organometallics have been reviewed in the treatise Comprehensive Supramolecular Chemistry [373, 374] and elsewhere [375, 376] and the subject will be surveyed only briefly here. 

Both types will be covered in this section. 

Most of the organometallic host-guest complexes of crown ethers and cryptands contain main group organometallic compounds. 

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