Covalently bonded fluorine as a sigma-donor for groups I and II metal ions in partially fluorinated macrocycles

The reaction of 1,3-bis(bromomethyl)-2-fluorobenzene with diaza-18-crown-6 produced novel fluoro cryptands and fluoro crown ethers in excellent yields. Analysis of the stability constants of the metal complexes of the fluoromacrocycles of these ethers and their fluorine free relatives suggests that the fluorine-containing macrocycles formed more stable metal complexes than the analogous fluorine free systems.