Bis mono-aza crown ethers. The formation of intramolecular complexes with dications
Abstract
The host molecules (4a–d), containing two crown ether ring systems, form 1 : 1 complexes (8) with the bis primary alkylammonium salt (7); in the cases of the host (4a) and (4b) guest–host fit is so good that only the intramolecular complex is formed, but for the other host molecules (4c) and (4d) the complex (8) is probably accompanied by the polymeric complex (9).