Institute of Nanostructure and Solid State Physics, University of Hamburg, 22761 Hamburg, Germany.
Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany.
Nat Chem. 2018 Mar;10(3):355-362. doi: 10.1038/nchem.2916. Epub 2018 Jan 15.
The entatic state denotes a distorted coordination geometry of a complex from its typical arrangement that generates an improvement to its function. The entatic-state principle has been observed to apply to copper electron-transfer proteins and it results in a lowering of the reorganization energy of the electron-transfer process. It is thus crucial for a multitude of biochemical processes, but its importance to photoactive complexes is unexplored. Here we study a copper complex-with a specifically designed constraining ligand geometry-that exhibits metal-to-ligand charge-transfer state lifetimes that are very short. The guanidine-quinoline ligand used here acts on the bis(chelated) copper(I) centre, allowing only small structural changes after photoexcitation that result in very fast structural dynamics. The data were collected using a multimethod approach that featured time-resolved ultraviolet-visible, infrared and X-ray absorption and optical emission spectroscopy. Through supporting density functional calculations, we deliver a detailed picture of the structural dynamics in the picosecond-to-nanosecond time range.
张弛态是指复合物的配位几何结构从典型排列中发生扭曲，从而改善其功能。张弛态原理已被观察到适用于铜电子转移蛋白，并导致电子转移过程的重组能降低。因此，它对多种生化过程至关重要，但它对光活性配合物的重要性尚未得到探索。在这里，我们研究了一种铜配合物——具有专门设计的约束配体几何形状——表现出金属到配体电荷转移态寿命非常短。这里使用的胍-喹啉配体作用于双（螯合）铜（I）中心，仅允许光激发后发生微小的结构变化，从而导致非常快速的结构动力学。数据是使用多方法方法收集的，该方法的特点是时间分辨紫外可见、红外和 X 射线吸收和光发射光谱。通过支持密度泛函计算，我们提供了在皮秒到纳秒时间范围内结构动力学的详细图像。
