Luz Christian, Oppel Kai, Endres Lukas, Dewhurst Rian D, Braunschweig Holger, Radius Udo
Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany.
Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany.
J Am Chem Soc. 2024 Aug 28;146(34):23741-23751. doi: 10.1021/jacs.4c04926. Epub 2024 Aug 13.
Borane coordination, B-H borane bond activation, and borane catenation via metal-mediated dehydrocoupling to form electron-precise B-B bonds are reported. The reaction of -[M(IMes)Cl] (M = W, Mo) (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) with borates Li[BHR] (R = Mes, Dur; Mes = 2,4,6-MeCH and Dur = 2,3,5,6-MeCH) afforded the complexes [M(IMes)(η-HBR)(η-HBR)] (M = W: R = Mes , R = Dur ; M = Mo: R = Mes , R = Dur ). Three borane ligands are coordinated in to the group 6 metal atom via five (σ-B-H) bonds. Reaction of with the phosphines PMe and PEt, respectively, led to the elimination of one of the borane ligands and afforded the hydrido (σ-B-H)-boryl bis(σ-B-H)-borane complexes -[W(IMes)(PR)(η-HBMes)(η-HBMes)(H)] (R = Me , R = Et ), in which the metal atom inserted into one of the remaining σ-B-H bonds of the borane ligands. Reaction of with an additional equivalent borane BHMes resulted in borane dehydrocoupling and formation of complex [W(IMes)(η-BHMes-BMes-BMes-BHMes)] , featuring a unique B chain as a ligand. Reaction of -[W(IMes)Cl] with NaBH also led to B-B coupling, and the metallaborane cluster [{W(IMes)(BH)}(BH)] was formed, in which two tungsten atoms bridge a B chain.
报道了通过金属介导的脱氢偶联形成电子精确的B-B键的硼烷配位、B-H硼烷键活化和硼烷成链反应。-[M(IMes)Cl]（M = W，Mo；IMes = 1,3-双(2,4,6-三甲基苯基)咪唑啉-2-亚基）与硼酸盐Li[BHR]（R = Mes，Dur；Mes = 2,4,6-MeCH，Dur = 2,3,5,6-MeCH）反应得到配合物[M(IMes)(η-HBR)(η-HBR)]（M = W：R = Mes，R = Dur；M = Mo：R = Mes，R = Dur）。三个硼烷配体通过五个(σ-B-H)键与第6族金属原子配位。分别与膦PMe和PEt反应，导致消除一个硼烷配体，得到氢化（σ-B-H）-硼基双（σ-B-H）-硼烷配合物-[W(IMes)(PR)(η-HBMes)(η-HBMes)(H)]（R = Me，R = Et），其中金属原子插入硼烷配体剩余的一个σ-B-H键中。与额外等量的硼烷BHMes反应导致硼烷脱氢偶联并形成配合物[W(IMes)(η-BHMes-BMes-BMes-BHMes)]，其具有独特的B链作为配体。-[W(IMes)Cl]与NaBH反应也导致B-B偶联，并形成金属硼烷簇[{W(IMes)(BH)}(BH)]，其中两个钨原子桥连一个B链。
