Jellyfish‐type Dinuclear Hafnium Azido Complexes: Synthesis and Reactivity.

Di‐ and multinuclear hafnium complexes bridged by ligands have been rarely reported. In this article, a novel 3,5‐disubstituted pyrazolate‐bridged ligand LH5 with two [N2N]2−‐type chelating side arms was designed and synthesized, which supported a series of dinuclear hafnium complexes. Dinuclear hafnium azides [LHf2(μ‐1,1‐N3)2(N3)2][Na(THF)4] 3 and [LHf2(μ‐1,1‐N3)2(N3)2][Na(2,2,2‐Kryptofix)] 4 were further synthesized and structurally characterized, featuring two sets of terminal and bridging azido ligands like jellyfishes. The reactivity of 3 under reduction conditions was conducted, leading to a formation of a tetranuclear hafnium imido complex [L1Hf2(μ1‐NH)(N3){μ2‐K}]25. DFT calculations revealed that the mixed imido azide 5 was generated via an intramolecular C−H insertion from a putative dinuclear HfIV‐nitridyl intermediate. [ABSTRACT FROM AUTHOR]