Lipophilic diazacrown

Lehn s approach is slightly more complex than that illustrated above in that the diol is chloromethylated and then treated with cyanide. Hydrolysis then affords the diacid which may be carried through as shown. It should also be noted that once the bis-acyl halide is in hand, it may be treated directly with an open-chained amine to yield a lipophilic diazacrown, after reduction ... 

Transport of Alkali Metal Perchlorates by Lipophilic Diazacrown Ethers. 

Transport rates for alkali metal perchlorates across bulk chloroform membranes by the lipophilic diazacrown compounds 9-11,14 and 15 are presented in Table 2. In all cases, transport of lithium and cesium perchlorates was undetectable. 

Comparison of the data for the lipophilic diazacrown ethers in Table 2 with that for the analogous crown ether compounds in Table 1 shows that replacement of two oxygen atoms in the macrocyclic ring with NH or NC2H5 units drastically reduces the alkali metal perchlorate transport. Presumably this results from diminished complexation of the hard alkali metal cations by the macrocyclic ligands when two hard oxygen donor sites are replaced by two nitrogen atoms. 

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See also in sourсe #XX -- [ ]

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