A Computational Investigation of the Electronic Properties of Partially Hydrogenated Fullerenes C60Hn (n = 18, 20, 24, 36 and 48)

Abstract

A DFT study is performed to investigate the electronic and magnetic properties of partially hydrogenated fullerenes C60Hn (n = 18, 20, 24, 36, and 48) based on NMR parameters, NICS, and NPA analysis. A few peaks appear in the 13C NMR pattern of each C60Hn, showing the electrostatic environments of C nuclei are divided into a few layers that are related to three local structures around C atoms. Since, hexagons and pentagons in the zone of hydrogenated carbons are puckered, the range of isotropic chemical shifts (δiso) for each group of carbons are caused by different curvatures at the corresponding sites. Partially hydrogenation of fullerenes results in isolated cyclohexatriene fragments with almost planarity surface, in some cases, which yields 13C δiso of 130.7–132.4 ppm. Moreover, cyclohexatriene pole ring with the calculated NICS value of −8.9 ppm at its center, similar to that of benzene (−8.0), can be considered as benzenoid fragment. Magnetic properties are also examined inside the compounds, indicating that NICS values are strongly negative in the middle of all the cages, except for C60H24 and C60H48. The predicted NICS values may be also useful for identification of the hydrogenated fullerenes through their endohedral 3He NMR chemical shifts.