在异金属金属有机框架中进行拓控制,通过离子模板和金属聚合物设计
Sara R Halper1, Loi Do, Jay R Stork
1Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, 92093-0358, USA.
Journal of the American Chemical Society
|November 23, 2006
概括
研究人员使用tris ((dipyrrinato)) 连接物和银盐合成了新的异金属金属有机框架 (MOF). 阳离子的选择显著影响MOF拓,使网络结构的合理设计成为可能.
科学领域:
- 材料化学 材料化学
- 超分子化学 超分子化学
- 协调化学 协调化学
背景情况:
- 金属有机框架 (MOF) 为各种应用提供可调节的结构.
- 了解控制MOF拓的因素对于材料设计至关重要.
- 异金属MOF为复杂的功能提供了机会.
研究的目的:
- 系统地研究核心金属离子,反离子和连接体结构对异金属MOF拓学的影响.
- 探索阴离子模板在MOF网络形成中的作用.
- 为了证明MOF合成的合理设计原则.
主要方法:
- 合成异金属MOFs使用tris ((dipyrrinato) 金属和各种银 ((I) 盐.
- 核心金属离子 (Fe3+,Co3+),反离子 (例如,AgOTf,AgBF4,AgPF6,AgSbF6) 和连接体结构的系统变化.
- 使用X射线晶体学进行表征,以确定网络拓,并通过单晶到单晶转换确认离子交换.
主要成果:
- Fe3+ 和 Co3+ 核心离子对 MOF 结构的影响微不足道,允许易于三金属 Fe/Co/Ag 网络合成.
- 对抗的选择显著影响了拓:AgOTf和AgBF4产生了3D (10,3) 网,而AgPF6和AgSbF6产生了2D (6,3) 蜂网.
- 阳离子交换实验在某些情况下证实了强大的拓,X射线晶体学揭示了单晶到单晶的转换.
- 连接体长度变化取代了离子模板,仅产生2D (6,3) 网.
结论:
- 阳离子模板是指导MOF拓的一个关键因素,但其协调能力不是主要的驱动因素.
- 连接体结构提供了控制MOF维度的替代途径,取代了离子效应.
- 这些发现为基于联体和离子选择的MOF架构的合理设计提供了基础.
相关概念视频
Properties 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.
Metal-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...
Crystal 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...
Valence 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...
Structural 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...
Coordination 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.


