The photoreactions of 2-isopropoxy-1,4-naphthoquinone in the presence of cobalt acetylacetonate and other organometallics: an esr and CIDEP study

2-Isopropoxy-1,4-naphthoquinone has been used as a photoredox reagent in non-silver imaging process. The present study showed that the photoreactions of this quinone are very sensitive to solvent due to the competing intramolecular hydrogen abstraction from the isopropoxy group. The presence of cobalt acetylacetonate often modifies the reactions which leads to a very high quantum efficiency of producing the radical intermediates. The ether oxygen in the 2-substituent provides a further coordinating site for organometallic compounds and the quinone behaves as a 1,2-quinone when interacting with metals.