Contrasting E-H Bond Activation Pathways of a Phosphanyl-Phosphagallene
Contrasting E-H Bond Activation Pathways of a Phosphanyl-Phosphagallene
复制标题
对比磷酰基-磷镓烯的 E-H 键激活途径
DOI：
10.1002/ange.202109334
复制
发表时间：
2021
影响因子：
--
通讯作者：
Feld J
中科院分区：
文献类型：
--
作者：
Feld J
报道了[H_2C{N(DIPP)}]_2PP=Ga(NacnAc)(NaC=HC[C(Me)N(DIPP)]2；DIPP=2，6-iPr2C6H3)与一系列具有E-−H键的试剂(伯胺、氨、水、苯乙炔、苯基膦和苯基硅烷)的反应活性。观察到了两条截然不同的反应路径，这两条路径由底物的E−H键的极性决定。在质子型试剂(δ−E−Hδ+)的情况下，受挫的刘易斯对类型的机制在室温下运行，其中金属镓中心充当刘易斯酸，悬挂的磷酰基部分使底物去质子化。有趣的是，在高温下，NH2 iPr和氨都可以通过第二条更高能量的途径反应，导致Ga=P键的氢胺化。相比之下，使用氢化物试剂(δ+E−Hδ−)，如苯基硅烷，只观察到Ga=P键的氢化作用，与Si−H和Ga=P键的极化一致。
The reactivity of the phosphanyl‐phosphagallene, [H2C{N(Dipp)}]2PP=Ga(Nacnac) (Nacnac=HC[C(Me)N(Dipp)]2; Dipp=2,6‐iPr2C6H3) towards a series of reagents possessing E−H bonds (primary amines, ammonia, water, phenylacetylene, phenylphosphine, and phenylsilane) is reported. Two contrasting reaction pathways are observed, determined by the polarity of the E−H bonds of the substrates. In the case of protic reagents (δ−E−Hδ+), a frustrated Lewis pair type of mechanism is operational at room temperature, in which the gallium metal centre acts as a Lewis acid and the pendant phosphanyl moiety deprotonates the substrates. Interestingly, at elevated temperatures both NH2iPr and ammonia can react via a second, higher energy, pathway resulting in the hydroamination of the Ga=P bond. By contrast, with hydridic reagents (δ+E−Hδ−), such as phenylsilane, hydroelementation of the Ga=P bond is exclusively observed, in line with the polarisation of the Si−H and Ga=P bonds.