Ge^II-H/Si^IV-H dehydrocoupling and cycloaddition chemistry of a Ni⁰ bis(hydridogermylene) complex

We report the high-yielding synthesis of a bis(hydridogermylene) complex of Ni⁰ (2). In contrast to known hydridotetrylene chemistry, this complex demonstrates a unique Ge^II-H/Si^IV-H dehydrocoupling reaction, resulting in the formation of an η³-[Ge₂Si]-Ni complex. Upon reaction with ethylene, a formal [2+2] cycloaddition across the non-bonded [Ge₂] unit in 2 is observed, forming a heavier metallacylopentane derivative. These results provide new insights into novel E-E bond-forming processes and the effect of metal coordination on the reactivity of E^II-H bonds (E = Si-Pb).