Flexible Coordination of N,P-Donor Ligands in Aluminum Dimethyl and Dihydride Complexes
Flexible Coordination of N,P-Donor Ligands in Aluminum Dimethyl and Dihydride Complexes
复制标题
DOI：
10.1021/acs.inorgchem.9b01061
复制
发表时间：
2019-09-02
影响因子：
4.6
通讯作者：
Cowley, Michael J.
中科院分区：
文献类型：
--
作者：
Falconer, Rosalyn L.;Nichol, Gary S.;Cowley, Michael J.
氢化铝曾经是一类简单的化学计量比的还原剂，现在正成为有机转化的有力催化剂，如不饱和键的氢化或氢化。P给体支持的氢化铝的配位化学研究相对较少。在这里，我们报道了氨基膦配体负载的二氢化铝和二甲基络合物，并研究了它们在溶液和固体中的配位行为。所有的配合物都以kappa(2)-N，P络合物的形式存在于固态。然而，我们发现，对于含有大量氨基膦供体的氨基膦配体，二氢化铝和二甲基络合物在溶液中发生“配体滑移”重排，生成kappa(2)-N，N络合物。因此，对于催化活性来说，我们发现P给体的配位行为可以通过控制它的空间体积来调节。结果表明，已报道的氢化铝催化了HBPin对炔烃的硼氢化反应，并且氨基膦配体表现出的不同配位方式调节了催化活性。
Aluminum hydrides, once a simple class of stoichiometric reductants, are now emerging as powerful catalysts for organic transformations such as the hydroboration or hydrogenation of unsaturated bonds. The coordination chemistry of aluminum hydrides supported by P donors is relatively underexplored. Here, we report aluminum dihydride and dimethyl complexes supported by amidophosphine ligands and study their coordination behavior in solution and in the solid state. All complexes exist as kappa(2)-N,P complexes in the solid state. However, we find that for amidophosphine ligands bearing bulky aminophosphine donors, aluminum dihydride and dimethyl complexes undergo a "ligand-slip" rearrangement in solution to generate kappa(2)-N,N complexes. Thus, importantly for catalytic activity, we find that the coordination behavior of the P donor can be modulated by controlling its steric bulk. We show that the reported aluminum hydrides catalyze the hydroboration of alkynes by HBPin and that the variable coordination mode exhibited by the amidophosphine ligand modulates the catalytic activity.