在{Mo18}宏循环中捕获[Mo3S4]4+集群,从而产生由动态H键网络稳定的超分子组合
Sylvain Duval1, Sébastien Floquet, Corine Simonnet-Jégat
1Institute Lavoisier of Versailles, University of Versailles Saint Quentin, 45 avenue des Etats Unis, 78035 Versailles Cedex, France.
Journal of the American Chemical Society
|January 23, 2010
概括
研究人员使用[Mo(3) S(4) ((Hnta) ((3))) ((2-) 复合体创建了最大的氧化聚环. 这种超分子附加物{1a-1b},在溶液中表现出独特的反应性和稳定性,双核单元被结在cis配置中.
科学领域:
- 无机化学 无机化学
- 超分子化学 超分子化学
- 材料科学 材料科学 材料科学
背景情况:
- 氧基聚化合物由于其独特的结构和反应性而引起人们的兴趣.
- 酸的自我凝结可以导致复杂的环结构.
- 三酸 (nta(3-)) 连接体在模板和稳定集群中发挥作用.
研究的目的:
- 为了合成和描述最大的氧基聚环结构.
- 为了研究形成的大氧基聚环和二核单元之间形成的超分子组合.
- 为了研究溶液中超分子 adduct 的稳定性和反应性.
主要方法:
- 对于固态结构的确定,进行X射线衍射分析.
- 使用各种NMR技术 (1D,COSY,NOESY,DOSY) 进行溶液状态表征.
- 单个物种和超分子 adduct 的合成.
主要成果:
- 形成一个大型的氧化分子环 {Mo(18) O(18) S(18) ((OH) ((18) } 模板由 [Mo(3) S(4) ((Hnta) ((3)) 2-) (1a).
- 一个双核单元{Mo(2)O(2)S(2)}的隔离,与nta(3-) 连接体协调,存在于cis (1b) 和trans (1b') 异构体.
- 通过结形成一个超分子 adduct {1a-1b} ,在溶液中稳定.
- 核磁共振研究证实了添加物的完整性,并揭示了双核单元的 cis-trans 均衡,该单元被结在添加物内的 cis 形式.
结论:
- [Mo(3) S(4) ((Hnta) ((3))) ((2-) 复合物有效地模拟了形成一个大型氧基聚环的模板.
- 在氧基聚环和双核单元之间可以形成稳定的超分子引体.
- 超分子组件影响二核元件的溶液行为,结其构造.
相关概念视频
Cycloaddition Reactions: MO Requirements for Thermal Activation
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
Molecular Orbital Theory II
Molecular Orbital Energy Diagrams
MO Theory and Covalent Bonding
The molecular orbital theory describes the distribution of electrons in molecules in a manner similar to the distribution of electrons in atomic orbitals. The region of space in which a valence electron in a molecule is likely to be found is called a molecular orbital. Mathematically, the linear combination of atomic orbitals (LCAO) generates molecular orbitals. Combinations of in-phase atomic orbital wave functions result in regions with a high probability of electron density, while...
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
Hückel's Rule Diagram of π MOs: Frost Circle
The Frost circle or the inscribed polygon method is a graphical method for determining the relative energies of π molecular orbitals (MOs) for planar, fully conjugated, and monocyclic compounds. This method was first described by A. A. Frost and Boris Musulin in 1953.
A Frost circle is constructed by drawing a polygon whose number of edges is equal to the number of carbons of the given cyclic system, with one of the vertices pointing down. Then, a circle is drawn enclosing the polygon so that...
A Frost circle is constructed by drawing a polygon whose number of edges is equal to the number of carbons of the given cyclic system, with one of the vertices pointing down. Then, a circle is drawn enclosing the polygon so that...
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...


