在高旋铁 ((II) 2,6-Bis ((pyrazolyl) pyridine复合体的协调几何中对角扭曲景观的调查
Izar Capel Berdiell1, Evridiki Michaels1, Orde Q Munro1
1School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
Inorganic chemistry
|January 23, 2024
概括
这项研究合成了一种具有高度扭曲几何的新型铁 (II) 复合体,揭示了对自旋交叉材料的洞察力. 电子捐赠配体促进结构扭曲,影响这些重要材料中的旋转转变.
科学领域:
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
- 计算化学的计算化学
背景情况:
- 旋转交叉 (SCO) 材料在分子电子和传感器研究中至关重要.
- 具有二氧化 (pyrazol-1-yl) 皮里丁 (bpp) 连接体的高旋铁 (II) 复合体是SCO的关键候选物.
- 在SCO综合体中的结构性扭曲显著影响其旋转过渡特性.
研究的目的:
- 为了合成和表征一种新的铁 (II) 复合物与一个二 (pyrazol-1-yl) 里丁连接体.
- 研究合成复合物的结构和电子特性,重点研究几何扭曲.
- 利用计算方法探索连接体替代剂对旋转交叉行为和扭曲格局的影响.
主要方法:
- 合成了连接物4-(3,4-dimethoxyphenylsulfanyl)-2,6-di(pyrazol-1-yl) pyridine (L) 的合成方法.
- 铁 (II) 复合物[FeL2][BF4]2 (1a) 和[FeL2][ClO4]2 (1b) 的制备和表征.
- 气相密度功能理论 (DFT) 计算 (ω-B97X-D/6-311G**) 用于建模结构路径和电子特性.
主要成果:
- 铁 (II) 复合体1a和1b表现出高旋转状态,具有前所未有的巨大六坐标几何扭曲.
- DFT计算确定了四个不同的结构路径,与相关复合体中的实验观测相关.
- 电子捐赠配体替代物,如硫基,在能量上有利于较小的扭曲和较低的扭曲路径处罚.
结论:
- 在1a和1b中观察到的大扭曲是单核复合体中报告的最显著的.
- 基替代物的电子效应直接影响Fe-N σ-结合,影响扭曲景观.
- 预计具有丰富电子的基捐赠体的铁 (II) 复合体在固态中会表现出合作自旋转换.
相关概念视频
02:42Valence Bond Theory
8.6K
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...
8.6K
03:02Colors and Magnetism
11.7K
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...
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...
11.7K
02:57Coordination Number and Geometry
15.8K
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.
15.8K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.6K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.6K
02:52Stereoisomerism
11.9K
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...
11.9K