A water-soluble supermolecular cage for artificial light-harvesting nanoreactors

Two discrete octahedral metallo-supramolecular cages were designed and constructed by using truxene-based pyridine L with enPd(NO3)2 or enPt(NO3)2, followed by detailed NMR, MS, UV absorption, and fluorescence spectroscopy. Owing to the determined cavity size and excellent optical performance of cages, the resulting supramolecular cages were confirmed to be the light-harvesting system based on Föster resonance energy-transfer (FRET). The developed cages display good water solubilities and can act as nanoreactors and light-harvesting systems to catalyze the difluoromethylation of quinoxalin-2(1H)-ones with sodium difluoromethanesulfinate under the irradiation of sunlight. Compared with eosin Y alone, this system displayed enhanced catalytic activity in catalyzing the difluoromethylation, which realizes the simulation of the photosynthesis process.