SYNTHESIS AND PHOTOOXIDATION OF SODIUM 1,3-CYCLOHEXADIENE-1,4-DIETHANOATE - A NEW COLORLESS AND WATER-SOLUBLE TRAP OF SINGLET OXYGEN

The sodium 1,3-cyclohexadiene-1,4-diethanoate has been designed as a n ew colorless trap for the measurement of photogenerated singlet oxygen in aqueous solution. Kinetic studies carried out by flash and steady- state photolysis have shown that this compound interacts with singlet oxygen via a pure chemical quenching with a rate constant k(r) equal t o (2.6 x 10(7) +/- 0.3) M(-1).s(-1). The two products obtained by phot ooxidation have been identified. The major one (88%) is a stable endop eroxide whereas the minor one (12%) is an hydroperoxide which decompos es into a phenolic derivative by prolongated warming at 37 degrees C.