Spherical fullerenes offer noteworthy structures usually involving six-and fivemembered faces, with application in technological issues. In this sense, cavernous spherical-like structures bearing larger holes provide interesting examples for further understanding of structure-properties relationship. Here, we explored the magnetic response of a proposed cavernous nitride fullerene, C 24 N 24 , which has a O h -symmetry with six N 4 -macrocyclic and eight 1,3,5-triazine faces displaying 48-π electrons. C 24 N 24 exhibits a local aromatic behavior owing to the contrasting antiaromatic response of the N 4 -macrocyclic faces and the aromatic character of the 1,3,5-triazine faces. Thus, the overall structure is ascribed as a local aromatic species, where the triazine faces exhibit the characteristic shielding cone for aromatic rings. Furthermore, the constructive combination of local shielding cones in C 24 N 24 delivers a related shielding-cone response, as expected for a perfect aromatic cage. Hence, the local aromatic/nonaromatic/antiaromatic sections exhibit an additive or subtractive interaction, leading to a characteristic response inherent to the nature of the spherical cage. We expect that further study of the interplay between different aromatic and antiaromatic faces in fullerene-like cages can deliver interesting pseudo-aromatic or pseudo-antiaromatic spherical species. K E Y W O R D S aromaticity, cavernous, fullerene, magnetic fields
| INTRODUCTIONFollowing the seminal discovery of buckminsterfullerene, [1][2][3] the field of related spherical structures has attracted interest from scientific community, resulting in an extensive and continuous growth of practical interdisciplinary applications with technological concerns. [4][5][6][7][8][9] C 60 , a spherical cage belonging to the icosahedral point group with sixty chemically equivalent sp 2 carbon atoms, provides a hollow structure with a high surface area, which is desirable for applications in lithium-ion batteries, [10][11][12] catalyst supports, [13,14] hydrogen storage, [15] solar cells, [16] and drug and gene delivery [5] , among others.Further surface modification of fullerenes by the so-called molecular surgical method [17][18][19] allows generating an open hole with the capability to including guest species, before the enclosure of the cavity. A similar structure has been proposed by Sundholm, [20,21] on the basis of Gaudi's architecture motifs, displaying an interesting cavernous structure with six open faces involving 72-π electrons coined as Gaudiene (O h -C 72 ).Despite the sizable cavities, it exhibits a spherical aromatic character given by the characterization of the magnetic response upon an external field from different orientations and follows a favorable electron count fulfilling the Hirsch's 2(N + 1) [2] rule for spherical aromatic species with N = 5. [22][23][24][25]
