控制分子内能量转移和氧气火的pH值,在Ru(II) 复合物中具有合电子激发状态的复合物
Tod A Grusenmeyer1, Jin Chen, Yuhuan Jin
1Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA.
Journal of the American Chemical Society
|April 3, 2012
概括
这项研究表明pH控制激发状态能量转移在复合体. 通过调整pH值,研究人员可以调整能量水平,增强发光氧传感器的发展.
科学领域:
- 光化学和光物理学
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
背景情况:
- 过渡金属复合物提供可调节的光物理性质.
- 在分子系统中,能量转移过程至关重要.
- 响应pH的配体可以调节电子状态.
研究的目的:
- 为了说明pH控制激发状态的能量转移在Ru(II) 复合体中.
- 研究pH,能量水平和兴奋状态寿命之间的关系.
- 探索开发发光氧传感器的潜力.
主要方法:
- 通过双二烯基连接物与二烯结合的Ru (II) 复合物的合成.
- 利用pH值的变化来改变 (3) MLCT状态的能量.
- 采用超快速和微秒时间分辨率的光谱学来分析激发状态衰变.
主要成果:
- Ru (II) 到碳氧-双二胺 (3) 的MLCT状态的能量是pH-依赖的.
- 增加pH导致 (3) MLCT状态能量增加,使发射寿命从2μs增加到>10μs.
- 兴奋状态被氧气火显示了pH的依赖,反映了兴奋状态的寿命.
结论:
- 激发状态平衡可以通过pH有效控制.
- 这种依赖pH值的能量传递机制对发光氧传感器设计具有前景.
- 这项研究强调了利用激发状态平衡在传感应用中的实用性.
相关概念视频
Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
Colors and Magnetism
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 eye.
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 eye.
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...
Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Oxidation of Phenols to Quinones
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Photochemical Electrocyclic Reactions: Stereochemistry
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


