Defined Dinuclear Nickel Sites on Mesoporous Silica Translate Molecular Surface Mimics to Heterogeneous Catalysis

Metal-metal cooperativity in dinuclear transition-metal systems offers unique opportunities for controlling reactivity and selectivity in catalytic transformations. Here, we report, inspired by molecular chemistry, the assembly of a bimetallic nickel system grafted onto mesoporous SBA-15 (Ni-NDI-APTES@SBA-15₂₅₀). The well-defined mesostructure of SBA-15 enables the immobilization of dinuclear nickel units while preserving their proximity and cooperative reactivity. Comprehensive characterization, including PXRD, N₂ physisorption, DRIFT-IR, S/TEM, XPS, EA, ICP-OES, TGA, and solid-state NMR, confirms the successful incorporation of Ni₂ species and retention of the mesoporous framework. The catalytic performance of Ni-NDI-APTES@SBA-15₂₅₀ was evaluated in the cyclotrimerization of terminal alkynes and compared with representative homogeneous mono- and dinuclear nickel catalysts. Ni-NDI-APTES@SBA-15₂₅₀ preserves the cooperative reactivity and high regioselectivity of the molecular dinuclear catalyst while the surface-bound environment introduces a distinct, substrate-dependent chemoselectivity, as exemplified by the selective monocyclotrimerization of diyne substrates instead of the double cyclization favored by the homogeneous analogue. Moreover, Ni-NDI-APTES@SBA-15₂₅₀ combines excellent catalytic performance with operational stability, recyclability, and negligible nickel leaching demonstrating that an immobilized catalyst can preserve molecular bimetallic reactivity while modulating catalytic pathways through the local supported environment.