Efficient sensitized photooxygenation in water by a porphyrin-cyclodextrin supramolecular complex

The 2:1 inclusion complex between (2,3,6-tri-O-methyl)-beta-cyclodextrin (TMbetaCD) and 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TPPS4) behaves as a supramolecular sensitizer in water providing photooxygenation with turnover numbers up to 30 000 with a very minor sensitizer bleaching (<10%). The protocol, which employs only 4 equiv of the cyclodextrin additive with respect to the porphyrin sensitizer (5 x 10(-7) M), leads to high yield oxidation of model biomolecules such as L-methionine methyl ester and uracil and is also effective for phenol degradation in aqueous solution.