超价,低坐标 (III) 中心在复合物中与酸盐连接体的phosphadiazonium子复合
Neil Burford1, Andrew D Phillips, Heather A Spinney
1Department of Chemistry and Atlantic Region Magnetic Resonance Centre, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada. neil.burford@dal.ca
Journal of the American Chemical Society
|March 18, 2005
概括
这项研究详细介绍了使用Mes*NPOTf和各种化联结体合成新的易斯酸复合物. 这些复合体展示了高价值,低坐标 (III) 中心,扩大了我们对化学的理解.
科学领域:
- 有机化学化学 有机化学
- 协调化学 协调化学
- 易斯的酸相互作用
背景情况:
- 具有较低协调数的化合物很少见,并且在合成上具有挑战性.
- 富含电子的中心可以表现出易斯酸度,挑战传统的定义.
- 了解高价是开发新试剂和催化剂的关键.
研究的目的:
- 合成和表征新的易斯酸复合体,具有高价值 (III) 中心.
- 为了研究多功能连接体与氏酸的协调行为.
- 探索这些独特复合物的结构和电子特性.
主要方法:
- 梅斯*NPOTf与结合剂配体 (2,2'-BIPY,TMEDA,DEPE,DIPHOS,PMDETA) 的反应.
- 分离和净化由此产生的易斯酸复合物.
- 单晶X射线衍射分析以确定分子结构.
主要成果:
- 五个新的易斯酸复合物的定量形成:[Mes*NP(L) ]][OTf].
- X射线衍射揭示了连接体捐赠者和中心之间的密切接触.
- 这些结构证实了phosphadiazonium离子的描述,并突出了的易斯酸度.
- 这些复合体是高价值,低坐标 (III) 系统的罕见例子.
结论:
- 富含电子的中心可以作为易斯酸,即使存在一个单一的对.
- 合成的复合物代表了对研究高价和低坐标化学的有价值的补充.
- 这些发现为进一步探索基于的易斯酸及其应用开辟了道路.
相关概念视频
Phosphodiester Linkages
Overview
Phosphodiester bond forms when a phosphoric acid molecule (H3PO4) links with two hydroxyl groups (–OH) of two other molecules, forming two ester bonds. Two water molecules are released in this process. The phosphodiester bond is commonly found in nucleic acids (DNA and RNA) and plays a critical role in their structure and function.
Phosphodiester Bonds Link Nucleotides Together
DNA and RNA are polynucleotides or long chains of nucleotides that are linked together. A nucleotide is...
Phosphodiester bond forms when a phosphoric acid molecule (H3PO4) links with two hydroxyl groups (–OH) of two other molecules, forming two ester bonds. Two water molecules are released in this process. The phosphodiester bond is commonly found in nucleic acids (DNA and RNA) and plays a critical role in their structure and function.
Phosphodiester Bonds Link Nucleotides Together
DNA and RNA are polynucleotides or long chains of nucleotides that are linked together. A nucleotide is...
Coordination Compounds and Nomenclature
In most main group element compounds, the valence electrons of the isolated atoms combine to form chemical bonds that satisfy the octet rule. For instance, the four valence electrons of carbon overlap with electrons from four hydrogen atoms to form CH4. The one valence electron leaves sodium and adds to the seven valence electrons of chlorine to form the ionic formula unit NaCl (Figure 1a). Transition metals do not normally bond in this fashion. They primarily form coordinate covalent bonds, a...
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...
Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
Complexation Equilibria: The Chelate Effect
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
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