Luo Zhixun, Reber Arthur C, Jia Meiye, Blades William H, Khanna Shiv N, Castleman A W
State Key Laboratory for Structural Chemistry of Unstable and Stable Species , Institute of Chemistry , Chinese Academy of Sciences , Beijing , 100190 , China . Email:
Departments of Chemistry and Physics , The Pennsylvania State University , University Park , PA 16802 , USA . Email:
Chem Sci. 2016 May 1;7(5):3067-3074. doi: 10.1039/c5sc04293c. Epub 2016 Jan 27.
Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms, enabling the classification of clusters as superatoms. The addition of ligands tunes the valence electron count of metal clusters and appears to serve as protecting groups preventing the etching of the metallic cores. Through a joint experimental and theoretical study of the reactivity of methanol with aluminum clusters ligated with iodine, we find that ligands enhance the stability of some clusters, however in some cases the electronegative ligand may perturb the charge density of the metallic core generating active sites that can lead to the etching of the cluster. The reactivity is driven by Lewis acid and Lewis base active sites that form through the selective positioning of the iodine and the structure of the aluminum core. This study enriches the general knowledge on clusters including offering insight into the stability of ligand protected clusters synthesized wet chemistry.
小金属团簇中的量子限域导致态聚集成类似于原子中壳层的电子壳层，从而能够将团簇分类为超原子。配体的加入调节了金属团簇的价电子数，并且似乎起到了保护基团的作用，防止金属核被蚀刻。通过对甲醇与碘配位的铝团簇反应性的联合实验和理论研究，我们发现配体增强了一些团簇的稳定性，然而在某些情况下，电负性配体可能会扰乱金属核的电荷密度，产生可导致团簇蚀刻的活性位点。反应性由通过碘的选择性定位和铝核结构形成的路易斯酸和路易斯碱活性位点驱动。这项研究丰富了关于团簇的一般知识，包括深入了解通过湿化学合成的配体保护团簇的稳定性。
