德国埃尔朗根-纽伦堡大学S. Harder小组在最新研究中，分离出强还原镁(0)配合物。 该项研究成果发表在2021年4月28日出版的《自然》杂志上。
该团队提供了由超大体积、单阴离子、β-二酮基配体稳定的零氧化态镁（即，镁（0））配合物的实例。然而，一个有机镁化合物的反应活性通常由其有机基团的亲核性和Mg2+阳离子的亲电性来定义，本文报道的Mg0配合物具有亲核性和强还原性的富电子Mg中心。后一种性质可以用将Na+还原为Na0的能力来证明。
该团队还提出了一个带有线性Mg3核的复合物，该复合物在形式上可以描述为MgI–Mg0–MgI单元。这种多核混合价态的Mgn簇被讨论为格氏试剂形成早期阶段的短暂中间体。它们具有极强的还原能力，具有丰富的反应活性和作为专用还原剂的应用价值。
据了解，一种零氧化态金属的复合物可以被认为是一种稳定的、但高度活性的单一金属原子形式。这种配合物在较贵的过渡金属中很常见。尽管电负性的晚主族p轨道占据的金属或半金属有少数已知例子，但要分离出零氧化态的早主族s轨道占据的金属仍是一个挑战。这与它们极低的电负性和强的氧化倾向直接相关。
附：英文原文
Title: Strongly reducing magnesium(0) complexes
Author: B. Rsch, T. X. Gentner, J. Eyselein, J. Langer, H. Elsen, S. Harder
Issue&Volume: 2021-04-28
Abstract: A complex of a metal in its zero oxidation state can be considered a stabilized, but highly reactive, form of a single metal atom. Such complexes are common for the more noble transition metals. Although rare examples are known for electronegative late-main-group p-block metals or semimetals1,2,3,4,5,6, it is a challenge to isolate early-main-group s-block metals in their zero oxidation state7,8,9,10,11. This is directly related to their very low electronegativity and strong tendency to oxidize. Here we present examples of zero-oxidation-state magnesium (that is, magnesium(0)) complexes that are stabilized by superbulky, monoanionic, β-diketiminate ligands. Whereas the reactivity of an organomagnesium compound is typically defined by the nucleophilicity of its organic groups and the electrophilicity of Mg2+ cations, the Mg0 complexes reported here feature electron-rich Mg centres that are nucleophilic and strongly reducing. The latter property is exemplified by the ability to reduce Na+ to Na0. We also present a complex with a linear Mg3 core that formally could be described as a MgI–Mg0–MgI unit. Such multinuclear mixed-valence Mgn clusters are discussed as fleeting intermediates during the early stages of Grignard reagent formation. Their remarkably strong reducing power implies a rich reactivity and application as specialized reducing agents.
DOI: 10.1038/s41586-021-03401-w
Source: https://www.nature.com/articles/s41586-021-03401-w