Excited-State Proton Transfer
Excited-State Proton Transfer
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DOI：
10.1007/978-1-4757-1634-4_20
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
L. Brand;W. Laws
中科院分区：
文献类型：
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作者：
L. Brand;W. Laws
电子激发态有机分子的化学和物理特性通常与其基态对应物有很大不同。这并不奇怪，因为紫外线或可见光的激发涉及电子云的扰动，而电子云决定了有机分子的化学键合特性。在短光脉冲激发后，处于基态且与其周围环境平衡的有机分子通常会相对于其环境处于亚稳态激发态。荧光衰减测量通常为研究随后达到激发态平衡的动力学提供了实验工具。激发态质子转移反应代表了一组经过充分研究和合理理解的激发态反应。 Försterland Weller2-4 的经典论文指出，有机酸表现出的激发态电离常数与基态电离常数相差几个数量级。几篇评论5-7描述了使用稳态荧光方法来估计激发态质子转移的速率常数。这些也可以在热力学考虑的帮助下从吸收和发射光谱理论上获得5,8,9（福斯特循环），这将在下面讨论。
The chemical and physical characteristics of organic molecules in their electronic excited states are usually quite different than those of their ground-state counterparts. This is not surprising, since excitation by ultraviolet or visible light involves perturbation of the electron cloud that determines the chemical bonding characteristics of organic molecules. Following excitation by a short impulse of light, organic molecules that were, in theirgroundstate, in equilibrium with their surroundings, will often be in a metastableexcitedstate with respect to their environment. Fluorescence decay measurements often provide an experimental tool for investigating the kinetics of the subsequent approach to the excited-state equilibrium. Excited-state proton transfer reactions represent a well studied and reasonably well understood group of excited-state reactions. The classic papers of Försterland Weller2–4established that organic acids exhibit excited-state ionization constants that differ by several orders of magnitude from those found in the ground state. Several reviews5–7describe the use ofsteady-statefluorescence methods for estimating the rate constants for excited-state proton transfer. These may also be obtained theoretically from absorption and emission spectra with the aid of thermodynamic considerations5,8,9(Förster cycle) which will be discussed below.