Complex formation between some di- and tervalent heavy metal cations and diaza crown ethers and cryptands in aqueous solution

摘要

The complexation of some di-and tervalent heavymetal cations in aqueous solution with diaza crown ethers andcryptands has more stable complexes with these cations comparedwith diaza crown ethers. The size of the cavity also influences thestability of the complexes formed. In contrast to EDTA only ion-dipole and covalent interactions between the ligands and thecations take place. Thus, it is not surprising that the complexstabilities of the diaza crown ethers and the cryptands with heavymetal cations are smaller than the stanbilities of the cation EDTA complexes.