New pyrrolidine and pyrroline derivatives of fullerenes: from the synthesis to the use in light-converting systems

The results of the authors' studies on the [2+3] cycloaddition of azomethine and nitrile ylides generated from picolylamine and benzylamine derivatives to fullerenes are systematized and new experimental data are considered. Catalysts and microwave radiation promoting the formation of ylides and their addition to fullerenes were successfully used for the first time. A large series of new pyrrolidine and pyrroline derivatives of fullerenes C-60 and C-70 were synthesized and characterized. The proposed procedures afford the reaction products in yields twice as high (80-85%) as those attained by the classical Prato reaction. The reactions proceed with virtually complete regio- (in the case of C-70) and stereoselectivity to afford only cis-2',5'-disubstituted and trans-1',2',5'-trisubstituted pyrrolidinofullerenes. Pyridyl-substituted pyrrolidinofullerenes react with metalloporphyrins and phthalocyanines to form self-ordered coordination complexes. The latter are analogs of natural photosynthetic antenna systems due to photoinduced charge separation that occurs in these complexes upon exposure to light.