Zhang Zhujun, Jiang Yihao, Li Jiang, Miyazaki Masayoshi, Kitano Masaaki, Hosono Hideo
MDX Research Center for Element Strategy, International Research Frontiers Initiative, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8503, Japan.
WPI-MANA, National Institute for Materials Science, Namiki, Tsukuba, Ibaraki 305-0044, Japan.
J Am Chem Soc. 2023 Oct 6;145(45):24482-5. doi: 10.1021/jacs.3c09362.
N activation is a key step in the industrial synthesis of ammonia and other high-value-added N-containing chemicals, and typically is heavily reliant on transition metal (TM) sites as active centers to reduce the large activation energy barrier for N dissociation. In the present work, we report that a 2D electride of BaN with anionic electrons in the interlayer spacings works efficiently for TM-free N dissociation under mild conditions. The interlayer electrons significantly boost N dissociation with a very small activation energy of 35 kJ mol, as confirmed by the N isotopic exchange reaction. The reaction of anionic electrons with N molecules stabilizes (N) anions, the so-called diazenide, in the large interlayer space (∼4.5 Å) sandwiched by 2 cationic slabs of BaN as the main intermediate.
氮活化是氨及其他高附加值含氮化学品工业合成中的关键步骤，通常严重依赖过渡金属（TM）位点作为活性中心来降低氮解离的巨大活化能垒。在本工作中，我们报道了一种层间距中含有阴离子电子的二维氮化钡电子化合物在温和条件下对无过渡金属的氮解离具有高效作用。通过氮同位素交换反应证实，层间电子以非常小的35 kJ/mol的活化能显著促进了氮解离。阴离子电子与氮分子的反应在由氮化钡的两个阳离子板层夹着的大层间空间（约4.5 Å）中稳定了（N）阴离子，即所谓的重氮化物，作为主要中间体。
