A designer 32-electron superatomic CBe8H12 cluster: core–shell geometry, octacoordinate carbon, and cubic aromaticity†
Abstract
Cubic octacoordinate carbon (coC) systems are extremely rare in chemistry. We report on a designer 32-electron coC CBe8H12 cluster, which has high Oh symmetry, being robust chemically and electronically, as well as dynamically up to 1200 K. Chemical bonding analysis establishes it as a core–shell cluster, consisting of cubic Be8H12 shell versus coC CBe8 core. The former is bound via Lewis-type three-center two-electron (3c-2e) Be–H–Be σ bonds and the latter features 8σ cubic aromaticity, collectively leading to a two-fold superatomic electron configuration. Cubic 8σ delocalization occurs in a truly three-dimensional fashion within the coC core, rather than on square surfaces only. The C center is in the s1p3 configuration, which uses 2s/2px/2py/2pz atomic orbitals equally in bonding with the Be8 cube, albeit without sp3 hybridization. The cubic cluster concept can be extended to alternative Oh Be8H122+ and NBe8H12+ clusters, the latter being a superalkali cation, which offers opportunities to tune the electronic properties.