Compounds and formulations suitable for radical scavenging

A Cx fullerene-derived ketolactam of formula I

• wherein x is 60, 70, 76, 78, 84, or 90;
• R is a C1-C50 hydrocarbon chain, branched or unbranched, with unsaturation from zero up to maximal, optionally substituted with an aryl group, heteroaryl group, halogen atom, hydroxyl group, a branched or unbranched, with unsaturation from zero up to maximal alkoxy group, or a branched or unbranched, with unsaturation from zero up to maximal alkanoyloxy group, said aryl or heteroaryl being optionally substituted with two or more groups, independently selected from the group consisting of halogen atoms, hydroxyl groups, C1-C50 hydrocarbon chains, branched or unbranched, with unsaturation from zero up to maximal alkyl group, C1-C50, branched or unbranched, with unsaturation from zero up to maximal alkoxy groups, C1-C50, branched or unbranched, with unsaturation from zero up to maximal alkanoyloxy groups, or —O(CH2CH2O)nR′ groups;
• n is 1 to 100 inclusive;
• and
• R′ is H, aryl, or a C1-C50 hydrocarbon chain, branched or unbranched, with unsaturation from zero up to maximal,
• further comprising:
• (a) one or more additional addends, each of which is fused to the fullerene cage at a distinct pair of adjacent carbon atoms in the fullerene cage;
• wherein each of the one or more additional addends is independently selected from the group consisting of a —C(Y)(Z)— group, a —C(R4R5)—N(R3)—C(R6R7)— group, and an oxygen atom;
• wherein Y and Z each independently represent optionally substituted aryl or alkyl;
• R6 represents optionally substituted aryl or aralkyl;
• and
• R3, R4, R5, and R7 are each independently optionally substituted alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, alkenyl, or aralkyl;
• or
• (b) an azafulleroid modification of the fullerene cage.