在二磁性组6中,有四基 (di-tert-butylketimido) 金属 (IV) 复合物
Rosanna A D Soriaga1, Jennifer M Nguyen, Thomas A Albright
1Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA.
Journal of the American Chemical Society
|December 4, 2010
概括
合成了新的金属复合物M(N=C-t-Bu(2)) ((4) (M=Cr,Mo,W).这些复合物包括: 这些复合体表现出平面四面体结构和二磁性质,通过分子轨道分析解释并通过量子力学计算得到证实.
科学领域:
- 有机金属化学 有机金属化学
- 无机合成 无机合成
- 固态化学 固态化学
背景情况:
- 探索具有独特连接体系统的新型金属复合体对于推进协调化学至关重要.
- 了解过渡金属化合物的电子结构和结合,可以了解它们的反应性和特性.
研究的目的:
- 为了合成和表征,和的新型金属胺复合物.
- 研究合成的M(N=C-t-Bu(2)) ((4) 复合物的结构,电子和磁性特性.
- 通过理论分析,阐明导致观察到的二磁性因素.
主要方法:
- 通过金属化物与LiN=C-t-Bu(2) 在乙烯中反应合成金属化物复合物.
- 使用单晶X射线衍射进行结构性表征.
- 光谱分析包括 (1) H 和 (13) C 的NMR.
- 使用定性分子轨道 (MO) 分析和密度功能/分子力学 (DFT/MM) 方法进行理论研究.
主要成果:
- 成功合成了M = Cr,Mo,W的四坐标复合物M(N=C-t-Bu(2))(4) 的成功合成.
- X射线衍射揭示了平整的四面体几何形状,大约具有D(2d) 对称性.
- 对于所有合成的复合物来说,NMR光谱表明了二磁性行为.
- 理论分析证实,联体轨道分裂金属d轨道,使得旋转配对和稳定的单元基态.
结论:
- 合成的金属胺复合物具有独特的结构和电子特性.
- 两磁性产生于由胺联体和金属中心决定的特定电子配置.
- 计算方法验证了实验观察结果,并提供了对这些复合物的结合和稳定性的洞察.
更多相关视频
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
10:52Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
相关概念视频
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.
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
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.
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...