同性感甲烯复合物:第一排过渡金属的"双金属烯"
Andrew E Ashley1, Robert T Cooper, Gregory G Wildgoose
1Chemistry Research Laboratory, Oxford University, Mansfield Rd, Oxford OX1 3TA, UK.
Journal of the American Chemical Society
|October 23, 2008
概括
研究人员合成和表征了双金属甲烯复合物 (Pn*2M2). 结构和光谱研究揭示了金属-金属结合和多种联结协调,DFT计算解释了观察到的特性.
科学领域:
- 有机金属化学 有机金属化学
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
背景情况:
- 双金属复合体具有独特的电子和结构性质.
- 甲基烯 (Pn*) 是一种重的连接物,能够稳定不寻常的金属框架.
- 了解这种复合体中的金属-金属结合对于催化和材料设计至关重要.
研究的目的:
- 为了合成和结构性地描述一系列双金属甲烯复合物 (Pn*2M2).
- 研究这些新型化合物的电子结构,粘合和磁性.
- 为了阐明甲烯联体的协调模式和金属对金属相互作用的性质.
主要方法:
- 合成Pn*2M2复合体 (M=V,Cr,Mn,Co,Ni) 的方法.
- 单晶X射线衍射用于固态结构的确定.
- 1H NMR光谱和可变温度磁感应度测量用于溶液和固态特性.
- 密度函数理论 (DFT) 计算以合理化实验数据并估计M-M债券订单.
主要成果:
- 成功合成并对Pn*2V2,Pn*2Cr2,Pn*2Mn2,Pn*2Co2和Pn*2Ni2.2进行了完整的结构性表征.
- 在Pn*2V2和Pn*2Mn2中观察到短的金属间距离,这表明金属与金属的结合.
- 在Pn*2Co2中的差异性结合 (eta(5):eta(3) 和在Pn*2Ni2.2.中的eta(3):eta(3) 结合.
- D(2h) 所有Pn*2M2物种的溶液中的分子对称性.
- 对于Pn*2Cr2的可变温度NMR显示了一个自旋配对的基本状态 (S=0) 与一个热可访问的兴奋状态 (S=1).
- Pn*2Mn2的磁感应性与S=1基本状态一致.
- 电化学研究揭示了复合物2-5的多重氧化还原过程.
- 不能合成Pn*2Fe2,只能产生甲二烯二聚物 (Pn*2).
结论:
- 该研究成功合成和表征了一系列双金属甲烯复合物,揭示了多种协调模式和金属对金属相互作用.
- DFT计算为电子结构和结合特性提供了宝贵的见解,补充了实验发现.
- 这些发现有助于理解低价值过渡金属复合体中的结合,以及体积庞大的配体在稳定独特结构中的作用.
更多相关视频
19:58Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
09:37Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
相关概念视频
01:23Properties of Organometallic Compounds
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
02:52Stereoisomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
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...
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
01:19Complexation Equilibria: The Chelate Effect
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...