Department of Chemistry, Daido University , Takiharu-cho, Minami-ku, Nagoya 457-8530, Japan.
PRESTO, Japan Science and Technology Agency (JST) , Honcho, Kawaguchi, Saitama 332-0012, Japan.
J Am Chem Soc. 2017 Apr 19;139(15):5596-5606. doi: 10.1021/jacs.7b01965. Epub 2017 Apr 10.
Multiple iron atoms bridged by hydrides is a common structural feature of the active species that have been postulated in the biological and industrial reduction of N. In this study, the reactions of an Fe(II) amide complex with pinacolborane in the presence/absence of phosphines afforded a series of hydride-supported [Fe] and [Fe] clusters Fe(μ-H)(μ-H){N(SiMe)}(PR) (PR = PMe (2a), PMePh (2b), PEt (2c)), Fe(μ-H)(μ-H)(PMe) (3), and (η-CH)Fe(μ-H){μ-N(SiMe)}{N(SiMe)} (4), which were characterized crystallographically and spectroscopically. Under ambient conditions, these clusters catalyzed the silylation of N to furnish up to 160 ± 13 equiv of N(SiMe) per 2c (40 equiv per Fe atom) and 183 ± 18 equiv per 3 (31 equiv per Fe atom). With regard to the generation of the reactive species, dissociation of phosphine and hydride ligands from the [Fe] and [Fe] clusters was indicated, based on the results of the mass spectrometric analysis on the [Fe] cluster, as well as the formation of a diphenylsilane adduct of the [Fe] cluster.
多个氢化物桥接的铁原子是生物和工业还原 N 中假定的活性物种的常见结构特征。在这项研究中，在膦存在/不存在的情况下，Fe(II)酰胺配合物与频哪醇硼烷反应，得到了一系列氢化物支持的[Fe]和[Fe]簇Fe(μ-H)(μ-H){N(SiMe)}(PR)(PR=PMe(2a)、PMePh(2b)、PEt(2c))、Fe(μ-H)(μ-H)(PMe)(3)和(η-CH)Fe(μ-H){μ-N(SiMe)}{N(SiMe)} (4)，它们通过晶体学和光谱学进行了表征。在环境条件下，这些簇催化了 N 的硅烷化反应，生成了高达 160±13 当量的 N(SiMe)（每个 2c 为 40 当量，每个 Fe 原子为 31 当量）和 183±18 当量每个 3（每个 Fe 原子为 31 当量）。关于活性物种的生成，基于对[Fe]簇的质谱分析结果以及[Fe]簇的二苯硅烷加合物的形成，表明了膦和氢化物配体从[Fe]和[Fe]簇中的解离。
