Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan.
J Am Chem Soc. 2021 Feb 3;143(4):1683-1698. doi: 10.1021/jacs.0c11465. Epub 2021 Jan 22.
Pure and doped gold/silver clusters protected by monolayers of organic ligands have attracted much interest as novel functional materials owing to their nonbulk-like, size-specific properties. They can be viewed as chemically modified superatoms because their stabilities and properties are governed by the electron shell configurations of the Au/Ag cores. Chemically modified superatoms are unique from conventional atoms in that they have additional control parameters such as surface modification, compositions, atomic packing, and size, although both of them follow similar Aufbau principles. Atomically precise synthesis and structure determination by X-ray crystallography have deepened our understanding of the correlation between the structures and fundamental properties of the superatoms. However, remaining challenges for the exploration of novel materials using superatoms as artificial elements at the nanoscale include (1) establishment of guiding principles of the electronic structures and (2) development of efficient, targeted synthesis according to rational design guidelines for functionalities. To address the first task, we herein propose and rationalize empirical guiding principles of electronic structures using icosahedral Au/Ag superatoms with the closed electron configuration as platforms. The second task is addressed by proposing design guidelines for functionalities and hydride-mediated transformation processes for efficient, targeted synthesis. These efforts will lead to the construction of a new periodic table of chemically modified superatoms and open up a materials world of quasi-molecules made of superatoms. We hope that this Perspective will contribute to the creation of a new paradigm based on superatoms, which parallels the matured world of molecular science.
由于具有非体相、尺寸特异性的性质，单层有机配体保护的纯金/银团簇作为新型功能材料引起了人们的极大兴趣。它们可以被视为化学修饰的超原子，因为它们的稳定性和性质受 Au/Ag 核的电子壳层构型控制。化学修饰的超原子与传统原子不同，它们具有额外的控制参数，如表面修饰、组成、原子堆积和尺寸，尽管它们都遵循类似的 Aufbau 原理。通过 X 射线晶体学进行的原子精确合成和结构确定加深了我们对超原子的结构和基本性质之间相关性的理解。然而，在纳米尺度上将超原子用作人工元素探索新型材料仍然面临挑战，包括 (1) 建立电子结构的指导原则，以及 (2) 根据功能的合理设计指南开发高效、有针对性的合成方法。为了解决第一个任务，我们在此提出并合理化了使用具有封闭电子构型的二十面体 Au/Ag 超原子作为平台的电子结构的经验指导原则。第二个任务通过提出功能的设计准则和氢化物介导的转化过程来解决，以实现高效、有针对性的合成。这些努力将导致构建一个新的化学修饰超原子的元素周期表，并开辟一个由超原子组成的准分子材料世界。我们希望这一观点将有助于基于超原子创造一个新的范式，这与成熟的分子科学世界并行不悖。
