SEARCH Articles Figures Tables Quenching of the triplet state of the sensitizer by the cis allyl phosphate, c s-1, generates the triplet state, T , of the 1,2-biradical 2. The 1,2-biradical is trapped by the phosphorus atom to afford the triplet state, TP, of the spirophosphoranyl 1,3-biradical 3. Then, inter-system crossing generates the [Publishers Imprint] [Publishers Imprint]