UV characterization and photodegradation mechanism of the fungicide chlorothalonil in the presence and absence of oxygen

- Franck-Condon resolved UV-Vis spectrum of Chlorothalonil.
- Photolysis and isomer speciation.
- Pesticide degradation pathways.

An experimental and theoretical study of the UV spectrum of chlorothalonil (CT) was carried out and the vibrationally resolved HOMO→LUMO transition is presented for the first time. The fluorescence spectrum has also been recorded. Furthermore, preparative photolysis allowed a detailed study of the photoproducts formed with recognition of different isomers. In the presence of oxygen only the first reductive dechlorination-decyanation occurred, while in its absence a successive dechlorination-decyanation takes place.

181