一个高旋铁的N2终端复合体 ((I) 在一个弱的三角形连接体场中
Alex McSkimming1, W Hill Harman1
1Department of Chemistry, University of California, Riverside, California 92521, United States.
Journal of the American Chemical Society
|July 3, 2015
概括
研究人员合成了新的高旋转铁复合物,这些复合物可以结合并激活气 (N2). 这一发现为生物和工业相关的固机制提供了新的见解.
科学领域:
- 生物有机化学 生物有机化学
- 有机金属化学 有机金属化学
- 固定的研究 固的研究
背景情况:
- 铁在生物和工业固定 (N2固定) 中的关键作用推动了对Fe-{NxHy}中间体的研究.
- 现有的低坐标Fe-(N2) 复合物经常使用捐赠接体,导致低/中等自旋状态或桥接动机,与酶活性位点的弱场硫化接体不同.
研究的目的:
- 合成和描述能够结合和激活N2.2的新型高旋铁复合体.
- 探索模仿酸酶活性部位中发现的高旋转酸中心的Fe-(N2) 复合体.
主要方法:
- 终端和桥梁Fe-(N2) 复合物的合成.
- 使用电子磁共振 (EPR) 和溶液磁矩测定进行表征.
- 振动光谱 (例如,红外光谱) 来评估NN键激活.
- 密度函数理论 (DFT) 计算以阐明电子结构.
主要成果:
- 报告了第一个高旋转 (S = 3/2) Fe的终端N2复合体.
- 合成了一个桥梁Fe-(N2)-Fe模拟物.
- 通过EPR和磁矩研究确认了高旋转状态.
- 振动数据表明NN债券的显著激活.
- DFT计算显示了终端 adduct 中的 N2 配体上的旋转移位.
结论:
- 成功合成和表征了前所未有的高旋转Fe (I) -N2复合体.
- 这些复合物在建模酶活性部位化学方面取得了重大进展.
- 这些发现为N2通过高旋转铁中心的激活提供了宝贵的见解,这与催化和生物无机化学有关.
相关概念视频
02:42Valence Bond Theory
11.7K
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...
11.7K
03:02Colors and Magnetism
14.7K
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...
14.7K
02:58Crystal Field Theory - Octahedral Complexes
31.9K
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...
31.9K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
49.8K
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,...
49.8K
01:17Spin–Spin Coupling: One-Bond Coupling
1.6K
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
1.6K
01:08Atomic Nuclei: Nuclear Spin
5.7K
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
5.7K