Silicon-Based Azo Compound-Mediated CO Activation and N₂ Release

Silicon-substituted azo compounds featuring Si─N═N─Si linkages remain elusive in main-group chemistry. Herein, we report the synthesis of a silicon-based azo compound generated directly from a mixed-valent silaiminyl-silylene precursor and a bulky organic azide. Unlike classical iminosilane formation, this reaction affords a thermally stable Si(IV)-azo species. Upon treatment with carbon monoxide (CO), this compound undergoes N₂ extrusion, complete C≡O bond cleavage, and formation of a formal Si(II)/Si(IV) product in which an oxygen atom bridges both silicon centers. Notably, the transformation incorporates the carbon atom into a DippNC byproduct via ligand rearrangement. A similar transformation occurs upon reaction with Fe(CO)₅, wherein N₂ release and CO cleavage also occur, but with the resulting Fe(CO)₄ fragment coordinating to the silicon center. These results demonstrate a rare example of silicon based azo-mediated small-molecule activation and highlight the potential of silicon-based systems for multi-electron redox chemistry typically associated with transition metals.