Crown ether styryl dyes: 22. Synthesis and complexation of the cis-isomers of photochromic aza-15-crown-5 ethers

Article abstract of DOI:10.1007/BF02496216

New crown ether-containing styryl dyes of the benzothiazole series containing an aza-15-crown-5-ether moiety were synthesized. The trans - cis-photoisomerization of these dyes and their analogs was studied; the effect of metal cations on the kinetics of dark cis -trans-isomerization was elucidated. The stability constants of the complexes of the cis-isomers of these dyes with Ca(ClO₄)₂ were estimated. The dramatic increase (by more than three orders of magnitude) in the stability of the complexes on passing from a cationic dye to a betaine was attributed to the formation of an intramolecular bond in the cis-complexes between the sulfo group of the N-substituent and the metal cation located in the cavity of the azacrown-ether moiety.