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.