The photochemistry of EDA complexes in micellar solutions. II. The stilbene–methylviologen system in the presence of oxygen

Abstract

The photolyses of electron donor–acceptor (EDA) complexes formed between both cis-stilbene (cS) and trans-stilbene (tS) as donors and mefhylviologen (MV +2 ) as acceptor have been carried out in homogeneous ethanolic and in micellar sodium dodecyl sulfate (SDS) solutions, in the presence of oxygen. The stilbene loss quantum yields (Φ −S ) have been determined in both media. Quantum yields were observed to be dependent upon methylviologen concentration and the acidity of media. A reaction scheme is proposed, which accounts for experimental results and can be related to the photochemistry of MV +2 and its cation radical MV •+ . Key words: EDA complexes, micelles, methyl viologen, stilbene.