Hydrogenolysis of Polysilanes Catalyzed by Low‐Valent Nickel Complexes

The dehydrogenation of organosilanes (RxSiH4−x) under the formation of Si−Si bonds is an intensively investigated process leading to oligo‐ or polysilanes. The reverse reaction is little studied. To date, the hydrogenolysis of Si−Si bonds requires very harsh conditions and is very unselective, leading to multiple side products. Herein, we describe a new catalytic hydrogenation of oligo‐ and polysilanes that is highly selective and proceeds under mild conditions. New low‐valent nickel hydride complexes are used as catalysts and secondary silanes, RR′SiH2, are obtained as products in high purity. Si−Si bonds in polysilanes can be converted to Si−H bonds under mild conditions by using low‐valent anionic Ni0 hydride catalysts. The reaction is reversible and dehydrogenative coupling of hydrosilanes is also possible. Experiments and DFT calculations indicate that low‐coordinated 14‐ and 16‐electron d10‐Ni hydrides, silyl, and silane intermediates are involved in the catalytic cycle.