[2+1] Cycloaddition of Nitrene onto C₆₀ Revisited: Interconversion between an Aziridinofullerene and an Azafulleroid

Abstract

Offen oder geschlossen? Die reversible Umwandlung eines [1,2]Aziridinofullerens in ein [1,6]Azafulleroid wurde bei derartigen monosubstituierten Fullerenen erstmalig beobachtet. Das [1,2]Aziridinofulleren lagert sich thermisch in das [1,6]Azafulleroid um, die Rückreaktion verläuft photochemisch mit hoher Ausbeute (siehe Bild).

Selective Functionalization of Fullerenes with N,N‐Dihalosulfonamides as an N1 Unit: Versatile Syntheses of Aza[60]fulleroids and Aziridino[60]fullerenes and their Application to Photovoltaic Cells

“…No isomerization was observed in either case. These results are consistent with the fact that isomerization between N ‐tosyl iminofullerenes 1 a and 2 a requires photochemical (from 1 a to 2 a )6a or thermal stimuli (from 2 a to 1 a ),11b although the ease of isomerization of other iminofullerenes would strongly depend on their N‐substituents 34. Thus, iminofullerenes 1 a and 2 a would be independently formed directly from C 60 in both cases, and not by way of these isomerization pathways…”

Photoinduced Charge Transfer in a Conformational Switching Chlorin Dimer–Azafulleroid in Polar and Nonpolar Media

“…The 1,3‐dipolar cycloaddition (1,3‐DC) of azide to the [6,6] bonds of C 60 followed by thermal extrusion of N 2 from the triazoline intermediate commonly leads to a mixture of two imino adducts, that is, open [5,6]‐bridged azafulleroids and closed [6,6]‐bridged aziridinofullerenes 14–19. The ratio of these two species depends on the nature of the substituent 15.…”

“…The 1,3-dipolar cycloaddition (1, of azide to the [6,6] bonds of C 60 followed by thermal extrusion of N 2 from the triazoline intermediate commonly leads to a mixture of two imino adducts, that is, open [5,6]-bridged azafulleroids and closed [6,6]-bridged aziridinofullerenes. [14][15][16][17][18][19] The ratio of these two species depends on the nature of the substituent. [15] The [6,6]triazoline intermediates lose N 2 immediately upon heating at temperatures slightly higher than 60 8C, [14,16,20] so this was not isolated or chemically characterized.…”

Fullerene C60 Architectures in Materials Science

“…The [1 + 2] cycloaddition involves divalent species, such as carbine, [23][24][25][26][27] nitrenes, [28][29][30][31][32] and silylenes, 33 to provide methanofullerenes and heteroanalogs. Sugar-C 60 type of molecules were achieved through reaction with sugar-derived spirodiazirines (Figure 2.3a).…”