Hanna Lauren, Long Conor L, Zhang Xiaoyi, Lockard Jenny V
Department of Chemistry, Rutgers University-Newark, Newark, NJ, USA.
Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA.
Chem Commun (Camb). 2020 Oct 1;56(78):11597-11600. doi: 10.1039/d0cc05339b.
Optical and X-ray spectroscopy studies reveal the location and role of Fe3+ sites incorporated through direct synthesis in NH2-MIL-125(Ti). Fe K-edge XAS analysis confirms its metal-oxo cluster node coordination while time-resolved optical and X-ray transient absorption studies disclose its role as an electron trap site, promoting long-lived photo-induced charge separation in the framework. Notably, XTA measurements show sustained electron reduction of the Fe sites into the microsecond time range. Comparison with an Fe-doped MOF generated through post-synthetic modification indicates that only the direct synthesis approach affords efficient Fe participation in the charge separated excited state.
光学和X射线光谱研究揭示了通过直接合成掺入NH2-MIL-125(Ti)中的Fe3+位点的位置和作用。Fe K边X射线吸收精细结构（XAS）分析证实了其与金属-氧簇节点的配位，而时间分辨光学和X射线瞬态吸收研究揭示了其作为电子陷阱位点的作用，促进了骨架中长寿命的光致电荷分离。值得注意的是，X射线瞬态吸收（XTA）测量表明Fe位点的电子还原持续到微秒时间范围。与通过后合成修饰生成的Fe掺杂金属有机框架（MOF）的比较表明，只有直接合成方法能使Fe有效地参与电荷分离激发态。
