Reactivity of Neutral Tantalum Sulfide Clusters TaS ( = 0-4) with N.

Nitrogen (N) fixation is a challenging and vital issue in chemistry. Inspired by the fact that the active sites of nitrogenases are polynuclear metal sulfide clusters, the reactivity of gas-phase metal sulfide clusters toward N has received considerable attention to gain fundamental insights into nitrogen fixation. Herein, neutral tantalum sulfide clusters have been prepared and their reactivity toward N has been investigated by mass spectrometry in conjunction with density functional theory (DFT) calculations. The experimental results showed that TaS ( = 0-3) could adsorb N, while TaS was inert to N The DFT calculations revealed that the complete cleavage of the N≡N bond on the trinuclear metal center in the TaS/N reaction systems was overall barrierless under thermal collision conditions. The sulfur ligands can facilitate the approaching of N toward the metal center but weaken the electron-donating ability of the metal center. The inertness of TaS is ascribed to the electron-deficient state of Ta in TaS and the least effective orbital interaction in the TaS/N couple. This study provides new insights into the ligand effect on the interaction of the metal clusters with N