Cooperative N-H bond activation by amido-Ge(ii) cations.

N-heterocyclic carbene (NHC) and tertiary phosphine-stabilized germylium-ylidene cations, [R(L)Ge:](+), featuring tethered amido substituents at R have been synthesizedviahalide abstraction. Characterization in the solid state by X-ray crystallography shows these systems to be monomeric, featuring a two-coordinate C,N- or P,N-ligated germanium atom. The presence of the strongly Lewis acidic cationic germanium centre and proximal amide function allows for facile cleavage of N-H bonds in 1,2-fashion: the products resulting from reactions with carbazole feature a tethered secondary amine donor bound to a three-coordinate carbazolyl-Ge(II)centre. In each case, addition of the components of the N-H bond occurs to the same face of the germanium amide function, consistent with a coordination/proton migration mechanism. Such as sequence is compatible with the idea that substrate coordinationviathe p pi orbital at germanium reduces the extent of N-to-Ge pi donation from the amide, thereby enhancing the basicity of the proximal N-group.