Seed John A, Deng Xinglan, Tomeček Josef, Brookfield Adam, Collison David, Tuna Floriana, Wooles Ashley J, Whitehead George F S, Kaltsoyannis Nikolas, Liddle Stephen T
Department of Chemistry, The University of Manchester, Manchester, UK.
Centre for Radiochemistry Research, The University of Manchester, Manchester, UK.
Nat Chem. 2025 Apr 11. doi: 10.1038/s41557-025-01790-3.
Quantum-confined nanoclusters can be described by the jellium model, which emphasizes closed-shell electron configurations, but an open-shell variation with jellium aromaticity has been proposed. Such clusters are termed superatoms because they behave like an atom, and they exhibit unusual properties. Superatoms feature metal-metal bonding; hence, since their discovery 40 years ago, superatoms have exclusively involved main group or transition metals, with actinides only considered computationally as dopants owing to actinide-actinide bonding being exceedingly rare. Here we report trithorium nanoclusters exhibiting three-centre-one-electron actinide-actinide bonding. Experimental and computational analysis demonstrates Robin-Day Class III 6d-orbital valence delocalization in these clusters. These S = 1/2 clusters are paramagnetic, but in external applied magnetic fields they exhibit exalted diamagnetism, evidencing actinide open-shell jellium aromaticity superatom character. Exalted diamagnetism is not normally associated with a single unpaired electron, but with a 1S magic number, the valence delocalization enables exalted diamagnetism, which is aromaticity, via superatom ring currents.
量子限域纳米团簇可以用凝胶模型来描述，该模型强调闭壳层电子构型，但有人提出了一种具有凝胶芳香性的开壳层变体。这类团簇被称为超原子，因为它们的行为类似于原子，并且表现出不同寻常的性质。超原子具有金属-金属键；因此，自40年前被发现以来，超原子只涉及主族或过渡金属，由于锕系元素之间的键极其罕见，锕系元素仅在计算中被视为掺杂剂。在此，我们报道了具有三中心单电子锕系-锕系键的三钍纳米团簇。实验和计算分析表明，这些团簇中存在罗宾-戴III类6d轨道价态离域。这些S = 1/2的团簇是顺磁性的，但在外部施加磁场时，它们表现出增强的抗磁性，证明了锕系开壳层凝胶芳香性超原子特征。增强的抗磁性通常与单个未成对电子无关，而是与1S幻数有关，价态离域通过超原子环流实现了增强的抗磁性，即芳香性。
