Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Int J Mol Sci. 2020 Sep 27;21(19):7125. doi: 10.3390/ijms21197125.
We report the generation of gold nanoparticles (AuNPs) from the aqueous solution of chloro(2,2',2″-terpyridine)gold(III) ion ([Au(tpy)Cl]) through X-ray radiolysis and optical excitation at a synchrotron. The original purpose of the experiment was to investigate the photoinduced structural changes of [Au(tpy)Cl] upon 400 nm excitation using time-resolved X-ray liquidography (TRXL). Initially, the TRXL data did not show any signal that would suggest structural changes of the solute molecule, but after an induction time, the TRXL data started to show sharp peaks and valleys. In the early phase, AuNPs with two types of morphology, dendrites, and spheres, were formed by the reducing action of hydrated electrons generated by the X-ray radiolysis of water, thereby allowing the detection of TRXL data due to the laser-induced lattice expansion and relaxation of AuNPs. Along with the lattice expansion, the dendritic and spherical AuNPs were transformed into smaller, raspberry-shaped AuNPs of a relatively uniform size via ablation by the optical femtosecond laser pulse used for the TRXL experiment. Density functional theory calculations confirm that the reduction potential of the metal complex relative to the hydration potential of X-ray-generated electrons determines the facile AuNP formation observed for [Au(tpy)Cl].
我们通过 X 射线辐射和同步加速器的光激发，从氯(2,2',2″-三联吡啶)金(III)离子([Au(tpy)Cl])的水溶液中生成了金纳米粒子(AuNPs)。该实验的最初目的是通过时间分辨 X 射线液相学(TRXL)研究在 400nm 激发下[Au(tpy)Cl]的光诱导结构变化。最初，TRXL 数据没有显示任何表明溶质分子结构变化的信号，但在诱导时间后，TRXL 数据开始显示出尖锐的峰和谷。在早期阶段，通过水的 X 射线辐射产生的水合电子的还原作用形成了两种形态的 AuNPs，即树枝状和球形，从而可以检测到由于激光诱导的晶格膨胀和 AuNPs 的弛豫而产生的 TRXL 数据。随着晶格的膨胀，树枝状和球形的 AuNPs 通过用于 TRXL 实验的光学飞秒激光脉冲的烧蚀，转化为相对均匀尺寸的较小的、覆盆子状的 AuNPs。密度泛函理论计算证实，相对于 X 射线产生的电子的水合势，金属配合物的还原势决定了[Au(tpy)Cl]中观察到的易于形成 AuNP。
