The activation of aryl-Br bonds was achieved by sequential combination of a triplet-triplet annihilation process of the organic dyes, butane-2,3-dione and 2,5-diphenyloxazole, with a single-electron-transfer activation of aryl bromides. The photophysical and chemical steps were studied by time-resolved transient fluorescence and absorption spectroscopy with a pulsed laser, quenching experiments, and DFT calculations.

Large unilamellar vesicles (100 nm) were functionalised to obtain supramolecular particles capable of light upconversion in pure aqueous media. Triplet-triplet annihilation of diphenylanthracene (DPA) leading to delayed fluorescence at 420 nm was used to upconvert the light absorbed by embedded metal complex sensitisers. The lipid type and the chromophore position in the membrane affect the TTA intensity, which remains constant over a large concentration range. 941 943 1717; Tel: +49 941 943 4575 † Electronic supplementary information (ESI) available. See