Cryptates inorganic

Rodrguez-Cortias, R., Avecilla, F., Platas-lglesias, C., et al. (2002) Structural and photophysical properties of heterobimetallic 4f-Zn iminophenolate cryptates. Inorganic Chemistry, 41, 5336. 

Sodium or potassium ions can also participate in the phase-transfer process when they are converted to lipophilic cations by complexation or by strong specific solvation. A variety of neutral organic compounds are able to form reasonably stable complexes with K+ or Na + and can act as catalysts in typical phase-transfer processes. Such compounds include monocyclic polyethers, or crown ethers (1), and bicyclic aminopolyethers (cryptates) (2). They can solubilize inorganic salts in nonpolar solvents and are particularly recommended for reactions of naked anions. Applications of these compounds have been studied.12,21-31... 

Inorganic cryptates in which a metal cation is enclosed in an inorganic cage structure have been reported [2.76,2.77]. 

The question of carrier design was first addressed for the transport of inorganic cations. In fact, selective alkali cation transport was one of the initial objectives of our work on cryptates [1.26a, 6.4]. Natural acyclic and macrocyclic ligands (such as monensin, valinomycin, enniatin, nonactin, etc.) were found early on to act as selective ion carriers, ionophores and have been extensively studied, in particular in view of their antibiotic properties [1.21, 6.5]. The discovery of the cation binding properties of crown ethers and of cryptates led to active investigations of the ionophoretic properties of these synthetic compounds [2.3c, 6.1,6.2,6.4-6.13], The first step resides in the ability of these substances to lipophilize cations by complexation and to extract them into an organic or membrane phase [6.14, 6.15]. 

Leyrie, Synthesis and chemical behavior of the inorganic cryptates. Ammonium, alkali, and alkaline earth antimony tungstates [MSb9W2i084 " Mn = Na, K, NH4, Ca, Sr, Inorg. Nucl. Chem. 42 1583(1980)... 

This applies especially to cryptates, since they lack contact to the complexed cation whereas in coronates and podates this contact is possible, in principle. Summing up crown compounds facilitate solution of inorganic salts in organic media and at the same time activate the anion. The preparative usefulness is obvious the reaction components, which on account of different polarities cannot be united in a common solvent without further means, are now apt to react. Here completely new application fields for saltlike reagents open up. Many reactions that in former times were impossible or only possible with low yields can be carried out in the presence of crown compounds without any difficulty. 

The Crowns were found in the U.S.A. The Cryptates , a more recent French discovery, are mixed ether-amine macrocycles that not merely encircle the salts of inorganic cations, as Crowns do, but actually surround them in all directions, leading to somewhat tighter binding (Lehn, Sauvage, and Dietrich, 1970), and to very strong binding of strontium vts d vis calcium. Of the alkali metals, potassium is often preferred to sodium and lithium. 

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