Cationic binding by macrobicyclic polyethers

Diazapolyoxamacrobicyclic compounds form ex-ceptionally stable complexes in organic nonpolar solvents by enclosing certain cations in the tri-dimensional cavity. In the present work, by using hydrogen bonding properties of chloroform.Tetraoxa-1,10-diazabicyclo(8.5«5) eicosane(2.1.1), 4,7;13,16;21-Pentaoxa-,10-diazabicyclo(8,8.5)tricosane(2.2.1) and 4,7;13,16;21,24-Hexaoxa-,lO-diazabicyclo(8.8.8)hexacosane(2.2* have been investigated and shown to exist in solution in the"out,out" conformation. Hydrogen bonding of chloroform-d p_ to the sulphate ion, SO^ , occurs with a resultant band —1 appearing in the infra-re$ at 20550^ . Encapsulation of Cu (II) and Co (II) by (2.1.1), (2.2.1) and (2.2.2) has been followed by infra-red spectroscopy. From the partition coefficient values (2.2.1) has been shown to be a poor selective extractant of copper and cobalt. (2.1.1) shows preference for cobalt while (2.2.2) appears to extract copper effectively