Synthesis and cation-receptor properties of macrocyclic imines of anthraquinone

At the present study a series of crown-containing imines of 1-hydroxy-9,10-anthraquinone with donor and acceptor substituents at the anthraquinone nucleus were synthesized. Compounds were prepared photochemically from the corresponding photoactive 1-phenoxyanthraquinones and 4-aminobenzo-15-crown-5 ether. It was established spectrophotometrically that for crown-containing anthraquinone imines that are characterized by "imine-enamine" prototropic tautomerism, the insertion of acceptor substituents shifts the equilibrium to the "enamine" form. This shift leads to essential spectral changes in complexing chlor- and nitrocontaining macrocyclic imines of anthraquinone with alkali and alkaline-earth metal cations