INTERACTIONS BETWEEN PROTONATED AMINE, AZA-CROWN ETHER, AND CRYPTAND WITH DIBENZOCROWN ETHER STUDIED BY A NEW SPECTROPHOTOMETRIC TECHNIQUE

The stability constants for the complexation of a diprotonated diamine , a diaza crown ether, and a cryptand with dibenzo-18-crown-6 and dibe nzo-24-crown-8, have been studied in aqueous solution using a new spec trophotometric technique. Because of the complex formation, the solubi lity of the dibenzocrown ethers increases. Complex formation is possib le between diamines and dibenzocrown ethers with both 1:1 and 2:1 stoi chiometry. However, experimental data are insufficient to decide on th e actual stoichiometry of the complexes formed. By computing the stabi lity constants and comparing them with the corresponding results for m onoamines, it is possible to decide on the actual stoichiometry of the complexes. Under the experimental conditions only 1:1 complexes with diamines are formed.