Photochemistry of an Amphiphilic Benzothiazolium Styryl Chromoionophore Organized in Langmuir–Blodgett Films

The photochemical behavior of Langmuir–Blodgett films built up from an amphiphilic benzothiazolium styryl dye containing a 1,10-dithia-18-crown-6 ether group, both in free form and complexed with Ag⁺ cations, has been studied. The isomerization reaction was slower in the films by 2 orders of magnitude relative to the solution and caused the decomposition of chromoionophore aggregates. Prolonged photolysis of the films wdth visible light (λ> 420 nm) resulted in an almost complete cycloaddition reaction with the formation of a cyclobutane adduct. The photoprocess was found to be partially reversible on exposure to UV light (λ = 310 nm).