We describe the successful synthesis of the first mixed-cation (pseudoternary) amidoborane, Na[Li(NH2BH3)2], with theoretical hydrogen capacity of 11.1 wt%. Na[Li(NH2BH3)2] crystallizes triclinic (P) with a = 5.0197(4) Ã
, b = 7.1203(7) Ã
, c = 8.9198(9) Ã
, α = 103.003(6)°, β = 102.200(5)°, γ = 103.575(5)°, and V = 289.98(5) Ã
3 (Z = 2), as additionally confirmed by Density Functional Theory calculations. Its crystal structure is topologically different from those of its orthorhombic LiNH2BH3 and NaNH2BH3 constituents, with distinctly different coordination spheres of Li (3 N atoms and 1 hydride anion) and Na (6 hydride anions). Na[Li(NH2BH3)2], which may be viewed as a product of a Lewis acid (LiNH2BH3)/Lewis base (NaNH2BH3) reaction, is an important candidate for a novel lightweight hydrogen storage material. The title material decomposes at low temperature (with onset at 75 °C, 6.0% mass loss up to 110 °C, and an additional 3.0% up to 200 °C) while evolving hydrogen contaminated with ammonia.
我们描述了第一个混合阳离子(伪三元)
氨硼烷Na[Li(NH₂BH₃)₂]的成功合成,理论氢容量为11.1%。Na[Li(NH₂BH₃)₂]结晶为三斜晶系(P),晶格参数a = 5.0197(4) Å,b = 7.1203(7) Å,c = 8.9198(9) Å,α = 103.003(6)°,β = 102.200(5)°,γ = 103.575(5)°,体积V = 289.98(5) ų(Z = 2),并通过密度泛函理论计算进一步确认。其晶体结构在拓扑上与其正交晶系的LiNH₂BH₃和NaNH₂BH₃组分不同,Li(3个N原子和1个
氢化物阴离子)和Na(6个
氢化物阴离子)的配位环境明显不同。Na[Li(NH₂BH₃)₂]可以看作是
路易斯酸(LiNH₂BH₃)与路易斯碱(NaNH₂BH₃)反应的产物,是新型轻质储氢材料的重要候选。该材料在低温下分解(起始温度为75°C,到110°C时质量损失6.0%,到200°C时额外损失3.0%),释放的
氢气中混有
氨气。