Long-range magnetic response of toroidal boron structures: B16 and [Co@B16]−/3− species
A correlation between the long-range characteristics of the magnetic response of toroidal boron-based structures is given, involving the uncoordinated B16 cluster and the hypercoordinated [Co@B16]−/3− counterparts. It is found that the perfectly symmetrical doubly aromatic systems share common features, involving a continuous shielding region for the orientation-averaged response (isotropic), and a long-ranged shielding cone under a perpendicularly oriented applied field (Bextz). In contrast, the conflicting aromatic structure given by the slightly distorted species, exhibits an enhanced deshielding cone under Bextz, which dominates the isotropic character of the response. In addition, [Mn@B16]− and [Cu@B16]− clusters were evaluated, denoting the role of the coordinated metal atom in such property. This information is valuable to account for a global magnetic response driven by the bonding pattern acting in each respective compound, and for the possible characterization of intermolecular aggregates or extended structures via NMR experiments.