Cleavage of Two Hydrogen Molecules by Boryldisilenes

Activation of H₂ by compounds of main-group elements has received considerable attention. Herein, we report synthesis of novel monoboryl- and monoamino-substituted disilenes and their characterization by a combination of NMR spectroscopy and single-crystal X-ray diffraction analysis. The monoboryldisilene reacts with two molecules of H₂ to provide the corresponding trihydridodisilane and hydroborane, whereas the aminodisilene does not react with H₂ under the same conditions. The present results together with our previous results indicate that the presence of the boryl-substituent on the Si=Si double bond is essential to activate the H₂ molecule. The low lying empty 2p orbital on the boron atom that interacts effectively with the π*(Si=Si) orbital could be responsible for the activation of H₂.