A dizirconium trihydride
complex supported by a tetradentate carbon-centered tris(aryloxide)
ligand [{Na(dme)}<sub>3</sub>{(O<sub>3</sub>C)Zr}<sub>2</sub>(μ-H)<sub>3</sub>] (<b>2</b>; [O<sub>3</sub>C] = [(3,5-<sup><i>t</i></sup>Bu<sub>2</sub>-2-O−C<sub>6</sub>H<sub>2</sub>)<sub>3</sub>C]<sup>4–</sup>) was prepared by reacting [(O<sub>3</sub>C)Zr(thf)<sub>3</sub>] (<b>1</b>) with NaBHEt<sub>3</sub> in toluene. Exposure
of <b>2</b> in THF to CO<sub>2</sub> (1 atm) resulted in facile
insertion of CO<sub>2</sub> into Zr−H bonds, yielding a formate
complex [{Na(thf)<sub>2</sub>}<sub>3</sub>{(O<sub>3</sub>C)Zr}<sub>2</sub>(μ-O<sub>2</sub>CH)<sub>3</sub>] (<b>3</b>). Treatment
of <b>2</b> with P<sub>4</sub> in toluene led to formation of
[Na(thf)<sub>5</sub>][{Na(thf)<sub>2</sub>}<sub>2</sub>{(O<sub>3</sub>C)Zr}<sub>2</sub>(μ-P<sub>3</sub>)] (<b>4</b>) and PH<sub>3</sub>, in which hydrogenation of P<sub>4</sub> took place. Complex <b>2</b> reacted with Me<sub>3</sub>SiN<sub>3</sub> to afford an
azide-bridged cyclotrimer [{Na(thf)<sub>2</sub>}{(O<sub>3</sub>C)ZrN<sub>3</sub>(thf)}]<sub>3</sub> (<b>5</b>) with concomitant liberation
of Me<sub>3</sub>SiH. The molecular structures of these complexes <b>2</b>–<b>5</b> have been determined by X-ray diffraction
analyses
