Patent ID: 8758979

Claim:
A methanofullerene derivative comprising a fullerene core of general formula C 2x and at least one addend of general formula (I): wherein x is at least 10, and R 1 and R 2 represent separate or linked organic groups, provided that at least one of R 1 and R 2 has a structure of general formula (III): where R 4 is an organic group selected from alkylene, alkenylene, arylene, ether, thioether, and combinations thereof, and R 5 is selected from: where R 6 is CH 3 and R 7 is CH 3 , CH 2 CH 3 , or CH(CH 3 ) 2 , or R 6 is CH(CH 3 ) 2 and R 7 is CH(CH 3 ) 2 with the exception of the case where R 4 is an ether and R 5 has structure (IV).