Storing hydrogen efficiently in condensed materials is a key technical challenge. Tremendous efforts have been given to inorganic hydrides containing B-H, Al-H and/or N-H bonds, while organic compounds with a great variety and rich chemistry in manipulating C-H and unsaturated bonds, however, are undervalued mainly because of their unfavorable thermodynamics and selectivity in dehydrogenation. Here, we developed a new family of hydrogen storage material spanning across the domain of inorganic and organic hydrogenous compounds, namely metallo-N-heterocycles, utilizing the electron donating nature of alkali or alkaline earth metals to tune the electron densities of N-heterocyclic molecules to be suitable for hydrogen storage in terms of thermodynamic properties. Theoretical calculations reveal that the enthalpies of dehydrogenation (ΔH_d) of these metallo-N-heterocycles are dependent on the electronegativity of the metals. In line with our calculation results, sodium and lithium analogues of pyrrolides, imidazolides and carbazolides of distinct structures were synthesized and characterized for the first time, where the cation-π interaction was identified. More importantly, a reversible hydrogen absorption and desorption can be achieved over lithium carbazolide which has a hydrogen capacity as high as 6.5 wt% and a suitable enthalpy of dehydrogenation of 34.2 kJ mol^-1-H₂ for on-board hydrogen storage.

将氢有效地存储在冷凝材料中是一项关键的技术挑战。对于含有BH，Al-H和/或NH键的无机氢化物已做出了巨大的努力，而在操纵CH和不饱和键方面具有多种多样且化学性质丰富的有机化合物却被低估了，这主要是由于它们不利的热力学和选择性。脱氢。在这里，我们利用碱金属或碱土金属的电子给体性质来调节N杂环分子的电子密度，从而开发了一种新的储氢材料系列，该材料跨越了无机和有机含氢化合物的范畴，即金属N-杂环就热力学性质而言适合于储氢。理论计算表明，脱氢焓（ΔH这些金属-N-杂环的_d）取决于金属的电负性。根据我们的计算结果，首次合成并表征了结构不同的吡咯化物，咪唑化物和咔唑化物的钠和锂类似物，并鉴定了阳离子-π相互作用。更重要的是，在具有高达6.5重量％的氢容量和34.2kJ mol ^-1 -H ₂的合适的脱氢焓以用于车载氢存储的咔唑锂上，可以实现可逆的氢吸收和解吸。