Reactivity of a N-Coordinated Germylene-Borane Complex: From Ge→B to Ge→Ga Coordination.

Reactivity studies of the Ge II →B complex L(Cl)Ge⋅BH 3 (1; L=2-Et 2 NCH 2 -4,6-tBu 2 -C 6 H 2 ) were performed to determine the effect on the Ge II →B donation. N-coordinated compounds L(OtBu)Ge⋅BH 3 (2) and [LGe⋅BH 3 ] 2 (3) were prepared. The possible tuning of the Ge II →B interaction was proved experimentally, yielding compounds 1-PPh 2 -8-(LGe)-C 10 H 6 (4) and L(Cl)Ge⋅GaCl 3 (5) without a Ge II →B interaction. In 5, an unprecedented Ge II →Ga coordination was revealed. The experimental results were complemented by a theoretical study focusing on the bonding in 1-5. The different strength of the Ge II →E (E=B, Ga) donation was evaluated by using energy decomposition analysis. The basicity of different L(X)Ge groups through proton affinity is also assessed.