两个坐标的第一行过渡金属复合体,具有短的不支持的金属-金属键
Hao Lei1, Jing-Dong Guo, James C Fettinger
1Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
Journal of the American Chemical Society
|November 25, 2010
概括
这项研究报告了新型的过渡金属复合体,其特点是不支持的金属-金属键. 这些化合物表现出短的M-Fe键距离和dative键相互作用,由各种光谱和晶体学方法证实.
科学领域:
- 有机金属化学 有机金属化学
- 无机化学 无机化学 有机化学
- 协调化学 协调化学
背景情况:
- 过渡金属复合物在催化和材料科学中至关重要.
- 了解金属对金属的结合是设计新功能分子的关键.
- 无支的金属对金属债券具有独特的电子和结构特性.
研究的目的:
- 合成和描述新型的第一排过渡金属复合物与不支持的M-Fe键.
- 研究这些复杂物体的结构,电子和磁性特性.
- 通过实验和计算方法阐明金属与金属相互作用的性质.
主要方法:
- 盐转化为合成.盐转化为合成.
- 核磁共振 (NMR) 光谱学 ((1) H NMR).
- 紫外线光谱学.紫外线光谱学.
- 一个X射线晶体学.
- SQUID 的磁性测量.
- 莫斯巴乌尔光谱法. 莫斯巴乌尔光谱法.
- 密度函数理论 (DFT) 的计算.
主要成果:
- 成功合成了三个新的复合物: (3,5-(i) Pr2-Ar*) MFe(η(5) -C5H5) ((CO) 2 (M = Fe,Mn,Cr).这些复合物中,有三种复合物是:
- 鉴定证实了不同的金属中心和短的金属-金属结合距离 (Fe-Fe: 2.3931(8) Å; Mn-Fe: 2.4512(5) Å; Cr-Fe: 2.4887(5) Å).
- DFT的计算支持了实验结果,并揭示了金属原子之间的原始结合相互作用.
结论:
- 合成的复合物代表了一种新的化合物类别,具有不支持的M-Fe键.
- 短的M-M键距离表明了重要的金属对金属相互作用.
- 基因结合相互作用在稳定这些独特结构方面发挥着至关重要的作用.
更多相关视频
12:30Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework
Published on: April 9, 2018
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
相关概念视频
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.
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:57Coordination Number and Geometry
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
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.
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...