A theoretical study on the reaction of diazocompounds with C70 fullerene

Using density functional theory calculations, we investigated the chemical functionalization of a C-70 fullerene with diazocompounds which has been reported experimentally. The results indicate that the [5,6]-bond of the apex of C-70 is more reactive than the equatorial bonds toward the cycloaddition of the diazocompounds. The energetic stability of phenyl C-71 butyric acid methyl ester (PCBM)-type [5,6]fulleroids (products) shows the same trend (1 > 2 > 3 > 4) to that observed experimentally. The reaction energy for different isomers of [5,6]-fulleroids is in the range of -23.3 to -37.7 kcal/mol. Our frontier molecular orbital analysis explains the experimentally observed UV-vis spectrums and confirmed the formation of [5,6]-fulleroids rather than [6,6]-methanofullerenes. The electron-hole pair binding energy for C-70 is calculated to be about 0.6 to 0.9 eV. Theoretical H-1-nuclear magnetic resonance (NMR), in good agreement with the corresponding experimental data, was used to more investigate the structure of the most stable complex. (C) 2016 Elsevier B.V. All rights reserved.