CROWN-ETHER STYRYL DYES .22. SYNTHESIS AND COMPLEXATION OF THE CIS-ISOMERS OF PHOTOCHROMIC AZA-15-CROWN-5 ETHERS

New crown ether-containing styryl dyes of the benzothiazole series con taining an aza-15-crown-5-ether moiety were synthesized. The trans-cis -photoisomerization of these dyes and their analogs was studied; the e ffect of metal cations on the kinetics of dark cis-trans-isomerization was elucidated. The stability constants of the complexes of the cis-i somers of these dyes with Ca(ClO4)(2) were estimated. The dramatic inc rease (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 betwee n the sulfo group of the N-substituent and the metal cation located in the cavity of the azacrown-ether moiety.