Nickel Phosphinidene Molecular Clusters from Organocyclophosphine Precursors

We report a new family of nickel phosphinidene molecular clusters synthesized from the reaction of bis(1,5-cyclooctadiene)nickel(0) ([Ni(cod)₂ ]) with organocyclophosphine and trialkylphosphine. We found that [Ni(cod)₂ ] cleaves the organocyclophosphine P-P bonds to generate phosphinidene groups, establishing the cyclic molecules as valuable precursors for making charge-neutral molecular clusters passivated by two-electron donor capping ligands. The formation of the cluster core structure is controlled by the bulkiness of the precursor and of the capping ligand. As a demonstration of this new cluster-forming reaction, we describe three clusters with different core nuclearity and degree of ligation: Ni₁₂ (PMe)₁₀ (PEt₃ )₈ , Ni₈ (PMe)₆ (PMe₃ )₈ , and Ni₈ (PiPr)₆ (PMe₃ )₆ . In addition, we show that the larger cluster, Ni₁₂ (PMe)₁₀ (PEt₃ )₈ , can be used as a low temperature single-source molecular precursor to the catalytically active nickel phosphide phase Ni₂ P.