Department of Chemistry , University of Victoria , 3800 Finnerty Road , Victoria , British Columbia V8P 5C2 , Canada.
Department of Chemistry , University of British Columbia , 2036 Main Mall , Vancouver , British Columbia V6T 1Z1 , Canada.
J Am Chem Soc. 2019 Dec 26;141(51):20009-20015. doi: 10.1021/jacs.9b11112. Epub 2019 Dec 11.
We report well-defined Ti(III) metallocene complexes CpTiMe () and CpTiH () (Cp* = η-CMe) as the first isolable early transition metal precatalysts for the dehydropolymerization of amine-boranes RNH·BH. These earth-abundant metal catalysts combine high activity with broad substrate scope. In contrast to late transition metal catalysts, displays reactivity toward a variety of primary amine-boranes, including those containing reactive moieties such as olefinic groups. The ability to functionalize the side chain of the resultant polyaminoborane [RNH-BH] provides a promising method for controlling properties. Mechanistic investigation of the dehydrogenation of secondary amine-borane MeNH·BH supports a bond-metathesis/β-hydride elimination, redox-neutral mechanism with a Ti(III)-H resting state.
我们报道了明确的 Ti(III)茂金属配合物 CpTiMe()和 CpTiH()（Cp*=η-CMe），它们是可分离的、用于胺硼烷的脱水聚合反应的首个早期过渡金属前催化剂。这些丰富的地球金属催化剂结合了高活性和广泛的底物范围。与后过渡金属催化剂相比，显示出对各种伯胺硼烷的反应活性，包括那些含有反应性部分如烯烃基团的胺硼烷。对所得聚胺硼烷[RNH-BH]的侧链进行官能化的能力为控制性能提供了一种很有前途的方法。对仲胺硼烷 MeNH·BH 的脱氢反应的机理研究支持了一种键交换/β-氢消除、氧化还原中性的机理，其中 Ti(III)-H 为休眠态。
