Ligand-Controlled Ni─C Bond Formation via Selective Gas-Phase C─C Bond Cleavage in 1,3-Diketones

Mechanistic investigations into the selective cleavage of C─C bonds to form M─C (M: metal) bonds are crucial for the comprehension, optimization, and design of chemical reactions. In this study, collision-induced dissociation (CID) experiments reveal that [(phen)NiL]⁺ (where L and phen represent a 1,3-diketone ligand and 1,10-phenanthroline, respectively), cations facilitate the selective cleavage of C─C bonds, leading to the formation of alkyl-metal ions possessing M─C bonds. In contrast, the [NiL]⁺ cation, without the phen ligand, produces small neutral molecules, such as CH₄, CO, and C₆H₆. Theoretical calculations suggest that a decarboxylation-like mechanism is responsible for the generation of the M─C bond in [(phen)Ni(bac)]⁺ (bac = benzoylacetone). Although the phen ligand is not directly involved in the fragmentation of nickel complex cations, it significantly alters the electronic structures and fragmentation mechanisms of nickel complex cations. This work presents a novel approach for the generation of M─C bonds through a gas-phase method and provides molecular-level insights into the selective cleavage of C─C bonds in homogeneous catalysis.