Femtosecond absorption spectroscopy of bis-aza-18-crown-6-containing dibenzylidenecyclobutanone complexes with alkali and alkaline-earth metal cations

Transient absorption spectroscopy, kinetics of absorption anisotropy decay for bis-aza-18-crown-6-containing di-benzylidenecyclobutanone dye and its metal complexes, and quantum chemical calculations support the presence of the first stage in the photorecoordination mechanism for the complexes with the Ba²⁺, Ca²⁺, and K⁺ cations. The depolarization parameters, including the radii of solvates, are deduced from the experimental data. During the barrierless photorecoordination of the complex with two Ba²⁺ cations, the solvent shell of the crowned Ba²⁺ cation undergoes the following changes: (2 + 1)MeCN, (3 + 1)MeCN, 4 MeCN.