Abstract
The synthesis of an arsanyl-phosphagallene [H(2)CN(Dipp)](2)AsP[double bond, length as m-dash]Ga(NacNac) (NacNac = HC[C(Me)N(Dipp)](2); Dipp = diisopropylphenyl) and its reactivity towards heterocumulenes and ketones is described. Reactions with azides, carbodiimides, isocyanates and ketones give rise to heterocycles via cyclization reactions involving the Ga[double bond, length as m-dash]P π-bond (with the Ga-P σ-bond remaining unperturbed in the final products). By contrast, reactions with CO(2), CS(2) and COS are more intriguing, revealing a reactivity profile in which the phosphorus atom can abstract carbon monoxide from the oxygen-containing heterocumulenes. These reactions result in the formation of gallium phosphaethynolate compounds. Such reactivity is enabled by the presence of a weakly Lewis basic arsanyl moiety which, in contrast to other related compounds featuring phosphanyl groups, is insufficiently nucleophilic to play a role in frustrated Lewis-pair like reactivity.