A comparative study on the reactivity of ditantalum deuteride cluster anions Ta2D2− and Ta2D4− toward N2

Abstract

The activation and transformation of molecular nitrogen (N₂) by metal hydride species has attracted widespread attention due to its critical role in nitrogen fixation. Herein, the reactions between tantalum deuteride cluster anions Ta₂D_2,4⁻ and N₂ were investigated experimentally and theoretically. An unprecedented reaction channel of the liberation of a single D atom was observed and much superior reactivity was identified for Ta₂D₄⁻. Theoretical investigations indicate that the releasing of D atoms benefits from the completely dissociative adsorption of N₂ on the dinuclear metal centres. The extra D atoms in Ta₂D₄⁻ compared to Ta₂D₂⁻ are helpful to create sufficient electron density at the adsorption site and modify the symmetry of active orbitals to facilitate a further reduction of N₂. This comparative study provides a molecular-level insight to understand the high structure-modulating capability of the additional hydride ligands in polyhydride species in the adsorption and activation of nitrogen molecules.