Study on the intermediate of photooxidative degradation of phenylenevinylene oligomers

The results of the investigation on photooxidative degradation of five phenylenevinylene oligomers are as follows. The sequence of the photodegradation rate in self-sensitized reaction is the same as that in the biacetyl-sensitized reaction and the rate of photooxidative degradation increases upon the incorporation of electron-donating groups and decreases upon the incorporation of electron-accepting groups on the oligomers. The self-sensitized reaction rate of oligomers increases as the solvent changing from benzene to deuterated benzene and decreases with the addition of the singlet oxygen (¹O₂) scavenger. ¹O₂ is shown to be the main reactive intermediate in self-sensitized photolysis of phenylenevinylene oligomers, which was directly confirmed by ESR spin trapping experiments.