Ultrastable actinide endohedral borospherenes

Since the discovery of the first all-boron fullerenes B , metal-doped borospherenes have received extensive attention. So far, in spite of theoretical efforts on metalloborospherenes, the feasibility of actinide analogues remains minimally explored. Here we report a series of actinide borospherenes AnB (An = U, Th; n = 36, 38, and 40) using DFT-PBE0 calculations. All the AnB complexes are found to possess endohedral structures (An@B ) as the global minima. In particular, U@B (C , A ) and Th@B (D , A ) exhibit nearly ideal endohedral borospherene structures. The C U@B and D Th@B complexes are predicted to be highly robust both thermodynamically and dynamically. In addition to the actinide size match to the cage, the covalent character of the metal-cage bonding in U@B and Th@B affords further stabilization. Bonding analysis indicates that U@B and Th@B can be qualified as 32-electron systems, and Th@B exhibits 3D aromaticity with σ plus π double delocalization bonding. The results demonstrate that doping with appropriate actinide atoms is promising to stabilize diverse borospherenes, and may provide routes for borospherene modification and functionalization.