史无前例的异构协调的Ir(C^N) 2tmd复合体,包含基于甲胺联体的五个和六个成员的Ir-(C^N) 环:合成,晶体结构和光物理性质
Sen Liu1,2, Mengyun Wang1, Tianjiao Hou1,3
1State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China. hou_tianjiao@njtech.edu.cn.
Dalton transactions (Cambridge, England : 2003)
|July 26, 2023
概括
研究人员合成了具有独特协调模式的新型红色发射复合体. 这些异质协调复合体具有独特的电子特性,并为设计基于的先进材料提供了洞察力.
科学领域:
- 有机金属化学 有机金属化学
- 材料科学 材料科学 材料科学
- 光物理学的光学物理学
背景情况:
- 循环金属化复合物对于有机发光二极管 (OLED) 来说至关重要.
- 控制复合体中的协调模式会影响它们的光物理和电化学特性.
- 具有不同金属循环大小的异构体复合体具有可调节的排放特性.
研究的目的:
- 合成和表征新型异构性复合物与混合的五和六成员金属循环.
- 研究不同协调模式对红色发射复合物的电子和光物理性质的影响.
- 为设计高效的基于的发射器提供更深入地了解结构-属性关系.
主要方法:
- 使用2-(9-phenanthryl) pyridine (phpyr) 衍生物和2,2,6,6-tetramethylheptane-3,5-dione (tmd) 的复合物的合成.
- 进行X射线晶体分析以确定异构体复合体的协调几何.
- 电化学分析和密度函数理论 (DFT) 计算用于研究电子结构和能量差距.
主要成果:
- 成功合成了异构体复合物,包括第一个具有五和六个成员金属环的异构协调的Ir (C^N) 2 (L^X) 型复合物的例子.
- 与双五环复合体相比,异构协调异构体表现出低色素辐射和较低的量子产量.
- DFT的计算显示,六个成员的金属循环稳定了LUMO,破坏了HOMO的稳定,缩小了能量差距.
结论:
- 该研究表明,复合物的混合五和六成员化模式导致了不同的光物理性质.
- DFT的计算和实验结果证实了 bis-five-membered 和 five- + six-membered 合模式相对于 bis-six-membered 模式的相对稳定性.
- 这项工作为合理设计具有量身定制的电子和光学特性的Ir{C^N) 2{L^X) 型复合体提供了宝贵的指导.
相关概念视频
01:13Five-Membered Heterocyclic Aromatic Compounds: Overview
4.0K
Heterocyclic aromatic compounds are cyclic compounds that are aromatic and have one or more heteroatoms—atoms other than carbon, in the ring. Depending upon the number of atoms present in the ring, they can be either five or six-membered. Examples of five-membered heterocyclic aromatic compounds include pyrrole, furan, thiophene, and imidazole. Pyrrole consists of one nitrogen atom having one lone pair of electrons. Furan and thiophene have one oxygen and one sulfur heteroatom,...
4.0K
01:18Aromatic Hydrocarbon Cations: Structural Overview
2.9K
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...
Removing one hydrogen from the intervening CH2 group...
2.9K
02:52Stereoisomerism
12.2K
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...
12.2K
02:34Structural Isomerism
19.4K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
19.4K
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.9K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.9K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.4K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.4K