Analysis of electronic delocalization in buckminsterfullerene (C₆₀)

Abstract

Buckminsterfullerene (C 60 ) presents an extensive conjugation that, in principle, should lead to a high delocalization of its electrons, together with a notorious aromaticity. However, previous studies have shown that C 60 behaves chemically and physically as an electron-deficient alkene rather than an electron-rich aromatic system. In the current work, we try to better elucidate the extension of electron delocalization in C 60 by computing the delocalization index for a given carbon atom of C 60 . We show that, in C 60 , local electron delocalization per carbon atom is lower than that in benzene and naphthalene. However, C 60 presents a global electron delocalization per carbon atom that is almost the same as that of clearly aromatic systems such as benzene or naphthalene. This is attributed to the fact that the electron charge of each atom in C 60 can be shared with a larger number of atoms.

Two-Dimensional Carbon: A Review of Synthesis Methods, and Electronic, Optical, and Vibrational Properties of Single-Layer Graphene

“…As mentioned in the previous section, graphene is a single layer of graphite sheet, and only sp 2 hybridization is featured [2]. In the case of fullerenes, the contribution of sp 3 hybridization limits the delocalization of electrons on the entire surface [33]. On the contrary, the complete predominance of sp 2 hybridization in graphene allows the formation of continuous delocalized molecular orbital deriving by π bonds, similar to the case of benzene previously reported [34,35].…”

“…Fullerene is a 0D carbon system constituted by a single shell of carbon atoms arranged in a sphere-like surface according to an ordinate polyhedral structure. For example, for the most abundant kind of fullerene, namely C 60 , the atom structure corresponds to a truncated icosahedron [33]. In general, various types of fullerene are obtained on varying the mixed contribution of sp 2 and sp 3 hybrid orbitals, with a further amount of the first one with increasing of fullerene size [2].…”

Aromaticity of Distorted Benzene Rings: Exploring the Validity of Different Indicators of Aromaticity

“…25,28 Third, most of the 6-MRs of fullerenes and buckybowls are known to be quite aromatic despite the important departure from planarity. [29][30][31][32][33][34][35][36] Theoretically, the flexibility of the benzene ring as well as the robustness of its π-electronic delocalization and aromatic character has been discussed in several works. Thus, Cyránski and Krygowski 37 analyzed the change in aromaticity of the benzene ring because of BLA (b 2u symmetry) and bond length elongation (BLE, a 1g symmetry) using the harmonic oscillator model of aromaticity (HOMA) index and the nucleus-independent chemical shifts (NICS) as indicators of aromaticity.…”

Probing Mechanistic Insights into Highly Efficient Lithium Storage of C60 Fullerene Enabled via Three‐Electron‐Redox Chemistry

“…The relatively large interstitials in between the C 60 clusters and the global electron delocalization in the C 60 clusters synergistically favor charge transfer and intermolecular lithium ion diffusion and contribute to the superior rate capability. [ 35 , 42 , 43 , 44 ] To examine the cycling stability of the C 60 cathode, GDC tests were performed at 0.2 C current rate for initial 2 cycles followed by 1 C current rate for another 50 cycles. As Figure 3f shows, the reversible capacity that the C 60 cathode delivered in EL‐3 electrolyte maintained at 91.9 mAh g −1 with a capacity retention rate of 83.9% after 50 cycles, along with an average discharge capacity of 99.1 mAh g −1 .…”