Electron and Spin Delocalization in [Co₆ Se₈ (PEt₃ )₆ ]^0/+1 Superatoms

Molecular clusters can function as nanoscale atoms/superatoms, assembling into superatomic solids, a new class of solid-state materials with designable properties through modifications on superatoms. To explore possibilities on diversifying building blocks, here we thoroughly studied one representative superatom, Co₆ Se₈ (PEt₃ )₆ . We probed its structural, electronic, and magnetic properties and revealed its detailed electronic structure as valence electrons delocalize over inorganic [Co₆ Se₈ ] core while ligands function as an insulated shell. ⁵⁹ Co SSNMR measurements on the core and ³¹ P, ¹³ C on the ligands show that the neutral Co₆ Se₈ (PEt₃ )₆ is diamagnetic and symmetric, with all ligands magnetically equivalent. Quantum computations cross-validate NMR results and reveal degenerate delocalized HOMO orbitals, indicating aromaticity. Ligand substitution keeps the inorganic core nearly intact. After losing one electron, the unpaired electron in [Co₆ Se₈ (PEt₃ )₆ ]⁺¹ is delocalized, causing paramagnetism and a delocalized electron spin. Notably, this feature of electron/spin delocalization over a large cluster is attractive for special single-electron devices.