Synthesis and properties of bis(pyrrolidino)fullerenes bridged by a flexible alkyl-tether

The one-pot bistycloaddition of alkyl-tethered diglycines to C-60 provided five series of bridged bis(pyrrolidino)fullerenes with good regioselectivity, giving mainly cis-2 and cis-3 products. An influence of the bridge length and addition pattern on spectroscopic properties, as well as on the shape of hierarchically organized supramolecular structures was observed. Additional investigation of all synthesized compounds confirmed their strong in vitro antioxidant activity 4-10-fold better than the standard antioxidant vitamin C.