McCusker James K
Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
Science. 2019 Feb 1;363(6426):484-488. doi: 10.1126/science.aav9104. Epub 2019 Jan 31.
Transition metal-based chromophores play a central role in a variety of light-enabled chemical processes ranging from artificial solar energy conversion to photoredox catalysis. The most commonly used compounds include elements from the second and third transition series (e.g., ruthenium and iridium), but their Earth-abundant first-row analogs fail to engage in photoinduced electron transfer chemistry despite having virtually identical absorptive properties. This disparate behavior stems from fundamental differences in the nature of 3d versus 4d and 5d orbitals, resulting in an inversion in the compounds' excited-state electronic structure and undermining the ability of compounds with first-row elements to engage in photoinduced electron transfer. This Review will survey the key experimental observations establishing this difference in behavior, discuss the underlying reasons for this phenomenon, and briefly summarize efforts that are currently under way to alter this paradigm and open the door to new opportunities for using Earth-abundant materials for photoinduced electron transfer chemistries.
基于过渡金属的发色团在从人工太阳能转换到光氧化还原催化等各种光驱动化学过程中起着核心作用。最常用的化合物包括第二和第三过渡系列的元素（例如钌和铱），但其储量丰富的第一排类似物尽管具有几乎相同的吸收特性，却无法参与光诱导电子转移化学过程。这种不同的行为源于3d与4d和5d轨道性质的根本差异，导致化合物激发态电子结构发生反转，并削弱了含有第一排元素的化合物参与光诱导电子转移的能力。本综述将概述确立这种行为差异的关键实验观察结果，讨论这一现象的潜在原因，并简要总结目前为改变这一模式所做的努力，为利用储量丰富的材料进行光诱导电子转移化学开辟新机遇。
