Photoinduced processes within compact dyads based on triphenylpyridinium-functionalized bipyridyl complexes of ruthenium(II).
Photoinduced processes within compact dyads based on triphenylpyridinium-functionalized bipyridyl complexes of ruthenium(II).
复制标题
基于三苯基吡啶功能化联吡啶钌 (II) 配合物的致密二元组内的光诱导过程。
作者：
P. Lainé;I. Ciofini;P. Ochsenbein;E. Amouyal;C. Adamo;F. Bedioui
作为一种替代传统的电荷分离功能分子模型的基础上长距离ET内的氧化还原级联，一个“紧凑的方法”已被审查。为此，通常插入在polyad系统内的主要氧化还原活性单元之间的间隔元件已被移除，从而允许扩展的刚性，但以增强的组件间电子通信为代价。本文研究的分子组装体是P-（θ（1））-A型的，其中θ（1）扭转角与光敏剂（{Ru（bpy）（3）}（2+）型的P1）和电子受体（A）之间的共轭程度有关。合成了4-N-和4-N-，4 ′-N-（2，4，6-三苯基吡啶）-2，2 ′-联吡啶配体（A（1）-bpy和A（2）-bpy），分别与Ru（II）、1-bpy和2-bpy形成配合物。结合固态分析（X射线晶体学），溶液研究（（1）H NMR，循环伏安法）和计算结构优化允许验证θ（1）角接近90度内1-bpy和2-bpy在溶液中。此外，通过研究化合物的电子吸收性质和电化学行为，已经证实了预期存在的强组分间电子耦合。1-bpy和2-bpy进行PET过程的能力进行了评估，通过进行其电子物理研究（稳态发射和时间分辨光谱在293和77 K）。通过比较1-bpy（和2-bpy）与文献中报道的一个附属物种1-phen的电子物理性质，建立了P-（theta（1））-A体系中光诱导过程的构象依赖性。本文对[1-bpy（θ（1））]（-）单还原态的自旋密度分布随θ（1）的变化进行了补充理论分析（DFT），并导出了P的构象转换发光性质的可能性。
As an alternative to conventional charge-separation functional molecular models based on long-range ET within redox cascades, a "compact approach" has been examined. To this end, spacer elements usually inserted between main redox-active units within polyad systems have been removed, allowing extended rigidity but at the expense of enhanced intercomponent electronic communication. The molecular assemblies investigated here are of the P-(theta (1))-A type, where the theta (1) twist angle is related to the degree of conjugation between the photosensitizer (P, of {Ru(bpy)(3)}(2+) type) and the electron-acceptor (A). 4-N- and 4-N-,4'-N-(2,4,6-triphenylpyridinio)-2,2'-bipyridine ligands (A(1)-bpy and A(2)-bpy, respectively) have been synthesized to give complexes with Ru(II), 1-bpy and 2-bpy, respectively. Combined solid-state analysis (X-ray crystallography), solution studies ((1)H NMR, cyclic voltammetry) and computational structural optimization allowed verifying that theta (1) angle approaches 90 degrees within 1-bpy and 2-bpy in solution. Also, anticipated existence of strong intercomponent electronic coupling has been confirmed by investigating electronic absorption properties and electrochemical behavior of the compounds. The capability of 1-bpy and 2-bpy to undergo PET process was evaluated by carrying out their photophysical study (steady state emission and time-resolved spectroscopy at both 293 and 77 K). The conformational dependence of photoinduced processes within P-(theta (1))-A systems has been established by comparing the photophysical properties of 1-bpy (and 2-bpy) with those of an affiliated species reported in the literature, 1-phen. A complementary theoretical analysis (DFT) of the change of spin density distribution within model [1-bpy(theta (1))](-) mono-reduced species as a function of theta (1) has been undertaken and the possibility of conformationally switching emission properties of P was derived.