PHOTOCHEMICAL cis/trans ISOMERIZATION OF AN AMPHIPHILIC MEROCYANINE DYE IN HOMOGENEOUS SOLUTION AND REVERSED MICELLES

Abstract— In the present study, the photochemical cis⇌trans isomerization of the amphiphilic merocy-anine dye (4-hydroxy-l-cetyl stilbazolium betaine C₁₆M) is reported. The structure of each isomer is established from high resolution FT ¹H-NMR analysis. The photochemical quantum yields φ_t→c, and φ_c→t are determined in methanol and in reversed micelles of the system (CDBA, benzene, water). The quantum yield φ_c→t increases in reversed micelles compared to that in methanol. The reverse results are obtained for φ_t→c. The micellar effect on the photochemical trans→cis isomerization will be discussed.