Contrasting E−H Bond Activation Pathways of a Phosphanyl‐Phosphagallene

The reactivity of the phosphanyl‐phosphagallene, [H(2)C{N(Dipp)}](2)PP=Ga(Nacnac) (Nacnac=HC[C(Me)N(Dipp)](2); Dipp=2,6‐( i )Pr(2)C(6)H(3)) 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−H(δ+)), 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 NH(2) ( i )Pr 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−H(δ−)), 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.