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Study of Singlet Oxygen Equilibrium in Dioctadecyldimethylammonium Chloride Vesicles Employing 2‐(n‐( N , N , N ‐trimethylamine)‐n‐alkyl)‐ 5‐alkylfuryl Halides †
Author(s) -
Zanocco Antonio L.,
Meléndrez Mónica,
Günther Germán,
Lemp Else
Publication year - 2007
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/2006-08-01-ra-991
Subject(s) - chemistry , singlet oxygen , bromide , bilayer , trimethylamine , photochemistry , iodide , equilibrium constant , alkyl , vesicle , oxygen , inorganic chemistry , organic chemistry , membrane , biochemistry
Steady state photolysis and time resolved near infrared luminescence detection were employed to study the reaction kinetics of singlet oxygen with three different lipid‐soluble probes incorporated in large unilamellar dioctadecyldimethylammonium chloride (DODAC) vesicles. The probes: 2‐(4‐( N , N , N ‐trimethylamine)‐butyl)‐5‐dodecylfuryl bromide (DFTA), 2‐(12‐( N , N , N ‐trimethylamine)‐dodecyl)‐5‐hexylfuryl bromide (HFDA) and 2‐(1‐( N , N , N ‐trimethylamine)‐methyl)‐5‐methylfuryl iodide (MFMA) are useful in studying both singlet oxygen dynamics and its equilibrium in microcompartmentalized systems because they are actinometers in lipidic microphases. These probes contain a reactive furan ring, which will be located at different depths in the bilayer of DODAC vesicles. In the limit of the approximations, the result indicates an inhomogeneous equilibrium distribution of singlet oxygen across the bilayer. The calculated mean partitioning constant of singlet oxygen equals 2.8 and 8.3 at 20°C and 40°C, respectively, in the order of the previously reported constants for other micro‐organized systems such as sodium dodecylsulfate and cetyltrimethylammonium halide micelles and water/oil microemulsions.