Solvatochromism as a mechanism for controlling intercomponent photoinduced processes in a bichromophoric complex containing [Ru(bpy)3]2+ and [Ru(bpy)(CN)4]2− units
Solvatochromism as a mechanism for controlling intercomponent photoinduced processes in a bichromophoric complex containing [Ru(bpy)3]2+ and [Ru(bpy)(CN)4]2− units
复制标题
溶剂变色作为控制含有 [Ru(bpy)3]2+ 和 [Ru(bpy)(CN)4]2− 单元的双发色团复合物中组分间光诱导过程的机制
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
F. Barigelletti
中科院分区：
文献类型：
--
作者：
N. M. Simpson;M. Ward;A. F. Morales;F. Barigelletti
双核配合物[（bpy）2Ru（μ-L1）Ru（CN）4]（1）含有{Ru（bpy）3} 2+型（Ru-bpy）和{Ru（bpy）（CN）4} 2 −型（Ru-CN）发色团，它们通过一个短的饱和-CH2OCH2CH2OCH2-链共价连接。由于Ru-CN发色团的物理化学性质强烈依赖于溶剂，而Ru-bpy发色团的物理化学性质则不依赖于溶剂，因此改变溶剂提供了改变组分间光诱导能量或电子转移过程的驱动力的手段。在室温下，在从纯水到纯DMSO的混合溶剂体系中，Ru-bpy单元的特征发光随DMSO比例的增加而逐渐猝灭。这些收费措施
与 * Ru-bpy一致
→
Ru-CN能量转移猝灭
→
* Ru-bpy电子转移猝灭，因为随着溶剂中dmso比例的增加，Ru-CN单元的3MLCT激发态的能量下降（这有利于能量转移过程），并且其Ru（III）/Ru（II）还原电位也变得不那么正（这有利于电子转移过程）。考虑到Ru-CN对Ru-bpy的发光猝灭发生的溶剂组成、间隔基的饱和性质以及金属-金属分离，共同指向福斯特能量转移是通过溶剂组成的变化而开启的猝灭过程。相比之下，在77 K（冷冻溶剂）下，Ru-CN单元的3MLCT状态的能量升高到高于Ru-bpy单元的能量，使得
能量转移梯度是相反的，并且 * Ru-CN
→
Ru-bpy能量转移发生在Ru-bpy末端的强发射。
The dinuclear complex [(bpy)2Ru(μ-L1)Ru(CN)4] (1) contains {Ru(bpy)3}2+-type (Ru-bpy) and {Ru(bpy)(CN)4}2−-type (Ru-CN) chromophores covalently linked by a short, saturated –CH2OCH2CH2OCH2– chain. Since the photophysical properties of the Ru-CN chromophore are strongly solvent-dependent, whereas those of the Ru-bpy chromophore are not, it follows that altering the solvent provides a means of altering the driving force for inter-component photoinduced energy- or electron transfer processes. At room temperature, in a mixed solvent system varying from pure water to pure dmso, the characteristic luminescence of the excited Ru-bpy unit is progressively quenched as the proportion of dmso in the mixture increases. This behaviour
is consistent with both *Ru-bpy
→
Ru-CN energy transfer quenching and with Ru-CN
→
*Ru-bpy electron transfer quenching, because as the proportion of dmso in the solvent increases, the 3MLCT excited state of the Ru-CN unit drops in energy (which facilitates the energy transfer process) and its Ru(III)/Ru(II) reduction potential also becomes less positive (which facilitates the electron transfer process). Consideration of the solvent composition at which luminescence quenching of Ru-bpy by Ru-CN occurs, the saturated nature of the spacer, and the metal–metal separation, collectively point towards Forster energy transfer being the quenching process which is switched on by the change in solvent composition. In contrast, at 77 K (frozen solvent) the 3MLCT state of the Ru-CN unit is raised in energy above that of the Ru-bpy unit, such that
the energy transfer gradient is reversed and *Ru-CN
→
Ru-bpy energy-transfer occurs with strong emission from the Ru-bpy terminus.