在区域异构体置换空间中的工程TADF,机色学和第二波上转换特性
Abhijit Chatterjee1, Joy Chatterjee1, Subrahmanyam Sappati2
1Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune 411008 Maharashtra India p.hazra@iiserpune.ac.in.
Chemical science
|December 11, 2023
概括
这项研究表明,dpapcn的副异构体由于最佳的电子特性,显示出优越的热激活延迟光效率 (tadf). 正态同位素,DPAOCN,显示独特的机色色发光和非线性光学特性,与其meta和para对应物不同.
科学领域:
- 有机化学 有机化学
- 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:
- 捐赠者-受体分子对于光电子应用至关重要.
- 区域同位素显著影响分子性质和固态行为.
- 了解结构属性关系是设计先进材料的关键.
研究的目的:
- 研究区域异构对TADF效率,晶体包装和散装特性的影响.
- 为了比较 ortho,meta 和 para 同体的光物理和非线性光学特性.
- 探索在光电子和传感方面的潜在应用.
主要方法:
- 合成了三种供体-受体区域异构体 (DPAOCN,DPAMCN,DPAPCN).
- 光物理特征包括溶液和固态TADF测量.
- X射线晶体学分析晶体包装和空洞体积.
- 机色发光和第二波生成 (SHG) 测量.
主要成果:
- DPAPCN (准异构体) 证明了最高的TADF效率,具有较快的RISC率 (∼10^6 s^-1),归因于最小的ΔEST和最大的SOC.
- 由于其非中心对称的晶体结构和空虚体积,DPAOCN (ortho-isomer) 呈现出可逆的三色机色色发光.
- 由于中心对称的包装,DPAPCN和DPAMCN (元异构体) 在机械上是惰性的.
- DPAOCN显示出出色的SHG特性 (χ(2) = 0.19 pm V^-1) 和高的LIDT (13.27 GW cm^-2).
结论:
- 区域异构性极大地影响了TADF的效率,晶体包装,以及由此产生的散装特性.
- 整形异构体为机色传感器和非线性光学设备提供了一个有前途的平台.
- 基于区域异构的战略分子设计可以解锁有机材料中的各种功能.
相关概念视频
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.8K
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
1.8K
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
3.1K
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
3.1K
02:52Stereoisomerism
11.9K
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...
11.9K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.0K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.0K
![[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12422.jpg&w=3840&q=75)
01:21[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
2.7K
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
2.7K
01:16Cycloaddition Reactions: MO Requirements for Thermal Activation
3.6K
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.
3.6K