Department of Chemistry and Biochemistry, The University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada.
Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada.
Inorg Chem. 2021 Jan 4;60(1):37-41. doi: 10.1021/acs.inorgchem.0c03409. Epub 2020 Dec 23.
Ligand design represents a central tenet of synthetic chemistry, wherein simple modification can lead to major differences in reactivity. Herein, we describe the preparation of two bis(diphosphino)nickel(II) hydride complexes that contain eight pendant boranes in their secondary coordination sphere, [Ni(H)(PB)] (R = Cy or Mes; Mes = 2,4,6-trimethylphenyl). Divergent reactivity of the cyclohexyl analogue toward the [NAD] model, 3-acetyl--benzylpyridinium bromide ([BNAcP]Br), is underscored. While [Ni(H)(PB)] undergoes rapid hydride transfer, the related species [Ni(H)(dnppe)] [dnppe = 1,2-bis(di--propylphosphino)ethane] and adduct [Ni(H)(PB)(DMAP)] (DMAP = 4-,-dimethylaminopyridine) exhibit no such reactivity. This borane-appended nickel(II) hydride distinguishes itself from its "all-alkyl" cousins and provides future opportunities for the design of [Ni(H)(diphosphine)] reagents for hydride transfer.
配体设计代表了合成化学的一个基本原则，其中简单的修饰可以导致反应性的重大差异。在此，我们描述了两种含有其次级配位球中的八个悬垂硼烷的双（二膦基）镍（II）氢化物配合物的制备，[Ni（H）（PB）]（R = Cy 或 Mes；Mes = 2,4,6-三甲基苯基）。环己基类似物对[NAD]模型，3-乙酰基--苄基吡啶溴化物（[BNAcP]Br）的不同反应性得到了强调。虽然[Ni（H）（PB）]经历快速氢转移，但相关的物种[Ni（H）（dnppe）][dnppe = 1,2-双（二--丙基膦基）乙烷]和加合物[Ni（H）（PB）（DMAP）]（DMAP = 4--，-二甲氨基吡啶）没有这种反应性。这种硼烷修饰的镍（II）氢化物与其“全烷基”同类物不同，为设计用于氢转移的[Ni（H）（二膦基）]试剂提供了未来的机会。
