Experimental and Theoretical Study of N(2) Adsorption on Hydrogenated Y(2)C(4)H(−) and Dehydrogenated Y(2)C(4)(−) Cluster Anions at Room Temperature

The adsorption of atmospheric dinitrogen (N(2)) on transition metal sites is an important topic in chemistry, which is regarded as the prerequisite for the activation of robust N≡N bonds in biological and industrial fields. Metal hydride bonds play an important part in the adsorption of N(2), while the role of hydrogen has not been comprehensively studied. Herein, we report the N(2) adsorption on the well-defined Y(2)C(4)H(0,1)(−) cluster anions under mild conditions by using mass spectrometry and density functional theory calculations. The mass spectrometry results reveal that the reactivity of N(2) adsorption on Y(2)C(4)H(−) is 50 times higher than that on Y(2)C(4)(−) clusters. Further analysis reveals the important role of the H atom: (1) the presence of the H atom modifies the charge distribution of the Y(2)C(4)H(−) anion; (2) the approach of N(2) to Y(2)C(4)H(−) is more favorable kinetically compared to that to Y(2)C(4)(−); and (3) a natural charge analysis shows that two Y atoms and one Y atom are the major electron donors in the Y(2)C(4)(−) and Y(2)C(4)H(−) anion clusters, respectively. This work provides new clues to the rational design of TM-based catalysts by efficiently doping hydrogen atoms to modulate the reactivity towards N(2).