Quenching of Singlet Oxygen by Sodium Azide in Reversed Micellar Systems

N o r i o M i y o s h i a n d G i i t i T o m i t a Institute o f Biophysics , Faculty o f Agriculture, K y u s h u University, F u k u o k a 812, Japan Z. Naturforsch. 34b , 339-343 (1979); received October 4, 1978 Singlet Oxygen , Sodium Azide, Diphenylisobenzofuran, Reversed Micelles The ox idat ion reaction of singlet oxygen with 1,3-diphenylisobenzofuran was investigated in cyclohexanic reversed micellar solutions o f d o d e c y l a m m o n i u m propionate , using pyrene as photosensitizer. The furan oxidation was effectively inhibited b y azide ion-bound reversed micelles. E m p t y reversed micelles also inhibited the furan oxidat ion t o some extent . The inhibition of the furan oxidation was due t o the quenching o f singlet o x y g e n b y azide ion-bound and empty reversed micelles. Such singlet o x y g e n quenching was dependent on the concentration of water added. Results obtained were discussed in connection with the polarity in the interior o f reversed micelles, micellar size, the state o f water solubilized in reversed micelles and the lifetime o f singlet oxygen. The heavy atom effect on the quenching o f singlet o x y g e n was also studied using heavy water.