Crown ether styryl dyes

Novel crown-containing styryl dyes (CSD) based on 15-crown-5-substituted benzothiazole with various electron-donating groups in thepara-position of the benzene ring were synthesized. Spectral and photochemical properties ofcis- andtrans-isomers of CSD and their complexes with Mg²⁺ ions in solutions were studied. By analysis of spectral parameters and the magnitudes and directions of the shifts of absorption (fluorescence) maxima, the effects of substituents and complex formation on the photochromism of CSD were elucidated. Using quantum-chemical calculations, the possibility of controlling the degree of participation of either of the two chromophores in the long-wave electron transition by complex formation was analyzed. For Part 19, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 999–1006, May, 1997.