A mono-coordinated gallium(I) ambiphile with redox-active and redox-inert reactivity

Abstract Mono-coordinated metallyenes (R–M:) of the Group 13 elements feature a non-bonding pair of electrons together with two vacant orbitals, which makes them highly reactive ambiphiles that readily activate small molecules by oxidative addition. In consequence of their pronounced reactivity, examples of mono-coordinated organometallics of aluminium(I) and gallium(I) remain rare. Here, we report the one-step synthesis of a monomeric gallium(I) compound that readily undergoes oxidative addition reactions and, more remarkably, carbometalation reactions with alkynes by retention of the low oxidation state +I and the coordination number one at gallium. This contrasts previous reports on the reactivity of low-valent main-group compounds, which are regularly oxidized to compounds in a more stable higher oxidation state. These findings provide a new approach to access low-valent main-group compounds and pave the way for the development of novel bond-functionalisation strategies that hence could enable the development of new catalytic processes in the future.