一个桥梁六烯 (RNNNNNNNR) 连接体,来自亚酸的还原性合
Ryan E Cowley1, Jérôme Elhaïk, Nathan A Eckert
1Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
Journal of the American Chemical Society
|April 19, 2008
概括
研究人员合成了具有独特RNNNNNNNR2-连接体的新型过渡金属复合体. 这些二铁复合体表现出了显著的热稳定性,通过二桥通过铁 (II) 离子之间的反铁磁合.
科学领域:
- 无机化学 无机化学
- 有机金属化学 有机金属化学
- 材料科学 材料科学 材料科学
背景情况:
- 过渡金属复合物在催化和材料科学中至关重要.
- 新联体的合成及其协调化学扩大了可访问的金属复合物的范围.
- 在金属复合体中探索新的结合动图和电子结构对于理解化学反应性至关重要.
研究的目的:
- 报告了首次合成和表征具有RNNNNNNR2-连接体的过渡金属复合物.
- 研究这些新型二铁复合物的结构,磁性和电子性质.
- 在二铁 (I) 框架中探索二离子RNNNNNNNR2-连接体的稳定性和结合特性.
主要方法:
- 合成具有不同R组 (甲基, tert-butyl) 的二铁 (I) 合成子.
- 铁 (I) 合成子与1-azidoadamantane反应,形成目标铁复合体.
- 使用磁感应度测量,Mössbauer光谱学和X射线晶体学进行表征.
主要成果:
- 成功合成含有二基AdN6Ad2-连接体的二铁复合体.
- 合成的复合物,L RFe ((mu-eta2:eta2-AdN6Ad) FeLR,显示出令人惊的热稳定性.
- 结晶学,磁性和Mössbauer数据证实了通过AdN6Ad2-桥通过抗铁磁合的两个高旋铁(II) 离子的存在.
结论:
- 该研究介绍了第一个包含RNNNNNNR2-连接体的过渡金属复合物的例子.
- 双铁复合体热稳定,并具有独特的桥梁连接体.
- 由二联体介导的高旋铁 (II) 中心之间的反铁磁合为多核金属复合体中的电子相互作用提供了洞察力.
相关概念视频
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
¹H NMR: Long-Range Coupling
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
Electrophilic Addition to Alkynes: Halogenation
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
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