旋转轨道合效应隐藏在光合性循环金属化Pt (II) 复合物的光物理背后
Thomas Groizard1, Souvik Mandal1, Christophe Gourlaouen1
1Laboratoire de Chimie Quantique Université de Strasbourg CNRS UMR7177, Institut Le Bel 4 Rue Blaise Pascal, 67000 Strasbourg, France. c.daniel@unistra.fr.
Physical chemistry chemical physics : PCCP
|June 25, 2025
概括
旋转轨道合显著影响着罗环金属复合物的光学特性. 连接体替代极大地改变光物理,其中一个复杂的由于近退化的发射状态而具有计算挑战性.
科学领域:
- 无机化学 无机化学 有机化学
- 计算化学计算化学
- 光物理学的光学物理学
背景情况:
- 环金属化 (Chiral cyclometalated platinum) 复合物表现出独特的光和光学特性.
- 了解这些复杂的电子和光学行为对于开发先进材料至关重要.
- 密度函数理论 (DFT) 和时间依赖DFT (TD-DFT) 是研究激发状态属性的强大工具.
研究的目的:
- 调查两种代表性的光奇拉环金属化Pt(II) 复合物的电子和奇罗光学特性:[Pt(pCpy) ((acac) ]和[Pt(pCpz) ((acac) ].
- 阐明旋转轨道合 (SOC) 在确定吸收,光和循环极化发光 (CPL) 光谱中的作用.
- 分析连接体替代 (pyridyl与pyrazolyl) 对光物理行为和计算挑战的影响.
主要方法:
- 使用密度函数理论 (DFT) 和时间依赖DFT (TD-DFT) 计算.
- 将内置的旋转轨道合 (SOC) 效应纳入理论框架.
- 模拟的早期 (<1 ps) 光物理使用非adiabatic量子动力学.
主要成果:
- SOC显著扰乱吸收光谱 (60-70纳米红移),并严格控制光和CPL强度和组成.
- 用pyrazolyl连接体取代一个pyridyl连接体极大地改变了最低的三重体状态的性质和能量.
- [Pt(pCpy) ((acac) ]在计算上很简单,而[Pt(pCpz) ((acac) ]由于两个几乎退化的发射三重状态而提出了挑战.
结论:
- 旋转轨道合是控制这些合性Pt(II) 复合体光物理性质的主导因素.
- 连接物选择对激发状态属性和排放特征产生深远影响,突显了这些系统的可调性.
- 这项研究提供了对循环金属Pt(II) 复合物的复杂光物理学的见解,有助于设计新型发光材料.
相关概念视频
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.1K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.1K
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
2.5K
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.
2.5K
03:02Colors and Magnetism
12.4K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.4K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.2K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.2K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.1K
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.
2.1K