Supramolecular architectures by fullerene-bridged bis(permethyl-beta-cyclodextrin)s with porphyrins.

The Hirsch-Bingel reaction of bis{4-methyl[1,2,3]triazolyl}malonic ester-bridged bis(permethyl-beta-cyclodextrin) 1 with C(60) has led to the formation of a new fullerene-bridged bis(permethyl-beta-cyclodextrin) 2, which has been comprehensively characterized by NMR spectroscopy, MALDI-MS, and elemental analysis. Taking advantage of the high affinity between 2 and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (3) or [5,10,15,20-tetrakis(4-sulfonatophenyl)porphinato]zinc(II) (4), linear supramolecular architectures with a width of about 2 nm and a length ranging from hundreds of nanometers to micron dimension were conveniently constructed and fully investigated by transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Significantly, the photoinduced electron-transfer (PET) process between porphyrin and C(60) moieties takes place within the 23 and 24 supramolecular architectures under light irradiation, leading to the highly efficient quenching of the porphyrin fluorescence. The PET process and the charge-separated state were investigated by means of fluorescence spectroscopy, fluorescence decay, cyclic voltammetry, and nanosecond transient absorption measurements.