Three-fold aromatic boranes: spherical aromaticity in borane ortho-carboranes as useful trimer nodes for cluster-based architectures

Abstract

The characterized tris(ortho-carboranyl)borane (BoCb₃) structure enables further understanding of building blocks in three-fold architectures as useful nodes for envisaging cluster-based materials, extending the already known linear array. Our results show the formation of shielding cones enabled in adjacent cluster units that overlap in long-range regions by different orientations of the applied field, in contrast to planar aromatic triarylborane counterparts. Thus, three spherical aromatic circuits or states are retained in the resulting molecular unit, as indicated by the isotropic and anisotropic descriptors of the magnetic behavior. In addition, the superacidic Lewis characteristics of BoCb₃, in comparison to triarylboranes, are enabled by the increase in the orbital interaction towards adduct formation, highlighting the relevance of the donor–acceptor charge transfer, where the control of steric repulsion may lead to further stabilization, suggesting plausible enhanced Lewis acidic performance. These results enhance the understanding of cluster-based architectures, paving the way for explorative synthesis efforts toward the achievement of novel superacidic Lewis species by using polyhedral standing molecules.