Demiao Ma, Xin Lei, Jianglu Yuan, Klavs Hansen, Zhixun Luo
Gas-phase reactivity of niobium clusters with haloalkanes studied using thermodynamic and kinetic analyses. Anionic niobium clusters react vigorously with haloalkanes via demethylation, yielding niobium-halide products; CH3I also undergoes dehydrogenation. Reactivity influenced by halogen substituents, providing foundation for rational design of niobium-based catalysts.
The catalytic cleavage of C-H and C-X (X = Cl, Br, I) bonds in alkanes and their halides over transition metals has drawn considerable attention due to the broad applicability in synthesizing commodity and fine chemicals. However, the dynamic reaction mechanisms of halomethanes on nanometals are still not fully understood. In this study, we report a comprehensive study into the gas-phase reactivity of niobium clusters Nbn - (n = 5-50) with haloalkanes CH3X (X = Cl, Br, I). These anionic clusters react vigorously with haloalkanes via an efficient demethylation pathway, yielding predominantly niobium-halide products NbnXm -, and the reactions of CH3I allow for both demethylation and dehydrogenation. Thermodynamic and kinetic analyses elucidate the reaction mechanisms and clarify how halogen substituents influence cluster-mediated reactivity. This work provides a solid foundation for the rational design of niobium-based catalysts constructed from superatom frameworks.