Zirconium Hydride Complex Supported by a Tetradentate Carbon-Centered Tripodal Tris(aryloxide) Ligand: Synthesis, Structure, and Reactivity

A dizirconium trihydride complex supported by a tetradentate carbon-centered tris­(aryloxide) ligand [{Na­(dme)}₃{(O₃C)­Zr}₂(μ-H)₃] (<b>2</b>; [O₃C] = [(3,5-^<i>t</i>Bu₂-2-O−C₆H₂)₃C]^4–) was prepared by reacting [(O₃C)­Zr­(thf)₃] (<b>1</b>) with NaBHEt₃ in toluene. Exposure of <b>2</b> in THF to CO₂ (1 atm) resulted in facile insertion of CO₂ into Zr−H bonds, yielding a formate complex [{Na­(thf)₂}₃{(O₃C)­Zr}₂(μ-O₂CH)₃] (<b>3</b>). Treatment of <b>2</b> with P₄ in toluene led to formation of [Na­(thf)₅]­[{Na­(thf)₂}₂{(O₃C)­Zr}₂(μ-P₃)] (<b>4</b>) and PH₃, in which hydrogenation of P₄ took place. Complex <b>2</b> reacted with Me₃SiN₃ to afford an azide-bridged cyclotrimer [{Na­(thf)₂}­{(O₃C)­ZrN₃(thf)}]₃ (<b>5</b>) with concomitant liberation of Me₃SiH. The molecular structures of these complexes <b>2</b>–<b>5</b> have been determined by X-ray diffraction analyses