DFT investigation on electrophilic and nucleophilic activities of some nitrogen-doped fullerenes, in comparison to C-60

摘要

C-60 fullerene, as an electron-deficient unit, participates easily in various nucleophilic addition reactions. Nonetheless, due to the low affinity of the C-60 to interact with electrophiles, a few studies have been done in this field. Nucleophilic and especially electrophilic activities of the fullerene cage could be improved by changing its electronic properties via heteroatom substitutions of its carbon atoms. In the present work, using DFT methods, we have investigated the electrophilic and nucleophilic activities of azafullerenes C40N20 and C42N18, and the results have been compared with those of the reference molecule C-60. The most active sites of different isomers of the target azafullerenes have been indicated by Fukui function, also using a comparative systematic method. Several parameters related to the additions of various electrophile and nucleophile species on the studied azafullerenes have been analyzed and compared with those additions on the C-60. It is concluded that the SN isomers of the both studied azafullerenes have stronger nucleophilic nature than of the fullerene C-60 (and NB isomers). In the case of electrophilic activity, the results show that the NB isomers of the both target azafullerenes are stronger than of the fullerene C-60 (and SN isomers). These are in the best agreement with the ionization potential and electron affinity of the studied isomers, also with their HOMO and LUMO energy levels.