黄金中的金属集群具有很大的HOMO-LUMO间隙和高电子亲和力
Yi Gao1, Satya Bulusu, Xiao Cheng Zeng
1Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
Journal of the American Chemical Society
|November 10, 2005
概括
新的金金属集群 (M@Au14) 显示出巨大的能量差距,超过已知的集群. 和变体 (M@Au14-) 呈现出异常的电子亲和力和脱离能,超过超素.
科学领域:
- 无机化学 无机化学
- 计算化学的计算化学
- 材料科学 材料科学 材料科学
背景情况:
- 黄金集群由于其独特的电子特性而引起人们的兴趣.
- 了解金属封装集群的稳定性和电子行为至关重要.
- 电子集群提供了一个平台来研究大小和组成对电子结构的影响.
研究的目的:
- 为了合成和描述新的同电子金金属集群M@Au14 (M = Zr, Hf) 和离子集群M@Au14- (M = Sc, Y).
- 通过计算来研究这些星团的电子性质,特别是这些星团的最高占有分子轨道-最低未占有分子轨道 (HOMO-LUMO) 间隙,电子亲和力 (EA) 和垂直分离能量 (VDE).
- 将它们的电子特性与Au20和Al13等超素等已建立的基准集群进行比较.
主要方法:
- 用密度函数理论 (DFT) 的计算来确定电子结构和属性.
- 计算的重点是优化集群几何和计算HOMO-LUMO差距,EA和VDEs.
- 利用同电子关系来设计和分析目标M@Au14和M@Au14-集群.
主要成果:
- 合成的M@Au14 (M = Zr, Hf) 和M@Au14- (M = Sc, Y) 集群被发现是异电子的.
- 所有报告的星团都显示出计算的HOMO-LUMO差距超过了众所周知的Au20星团 (1.77 eV) 的差距.
- M@Au14- (M = Sc, Y) 集群显示计算的EA和VDE值高于Al13超基集群,甚至可能有一个原子 (3.61 eV).
结论:
- 已经确定了具有显著电子特性的新型同电子金集群.
- 这些M@Au14和M@Au14-集群代表了先进电子和化学应用的有希望的候选人.
- 这些发现有助于对金属集群和超素中电子结构的基本理解.
相关概念视频
04:00Periodic Classification of the Elements
The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their electron configurations are added to the table, a periodic recurrence of similar electron configurations in the outer shells of these elements is observed. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. The outer electrons have the highest energy of the electrons in an atom...
02:32Bonding in Metals
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
02:37Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
02:58Properties of Transition Metals
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...