title: Study of singlet oxygen equilibrium in dioctadecyldimethylammonium chloride vesicles employing 2-(n-(N,N,N-trimethylamine)-n-alkyl)-5-alkylfuryl halides.
abstract: 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 degrees C and 40 degrees C, respectively, in the order of the previously reported constants for other microorganized systems such as sodium dodecylsulfate and cetyltrimethylammonium halide micelles and water/oil microemulsions.
authors.affiliation: Universidad de Chile, Facultad de Ciencias Químicas y Farmacéuticas, Departamento de Química Orgánica y Fisicoquímica, Santiago, Chile. azanocco@ciq.uchile.cl
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Zanocco
authors.forename: Mónica
authors.initials: M
authors.lastname: Meléndrez
authors.forename: Germán
authors.initials: G
authors.lastname: Günther
authors.forename: Else
authors.initials: E
authors.lastname: Lemp
mesh_terms: D007259:Infrared Rays; D008081:Liposomes / Q000737:chemistry*; D021962:Membrane Microdomains; D015335:Molecular Probes; D010782:Photolysis; D000644:Quaternary Ammonium Compounds; D026082:Singlet Oxygen
chemical_list: D008081:Liposomes; D015335:Molecular Probes; D000644:Quaternary Ammonium Compounds; D026082:Singlet Oxygen; C015831:dimethyldioctadecylammonium