화학공학소재연구정보센터
Inorganic Chemistry, Vol.58, No.8, 4753-4760, 2019
Complexation of Ammonia Boranes with Al3+
Ammonia borane, NH3BH3 (AB), is very attractive for hydrogen storage; however, it dehydrogenates exothermally, producing a mixture of polymeric products with limited potential for direct rehydrogenation. Recently, it was shown that AB complexed with Al3+ in Al(BH4)(3)center dot AB endothermically dehydrogenates to a single product identified as Al(BH4)(3)center dot NHBH, with the potential for direct rehydrogenation of AB. Here we explore the reactivity of AB-derived RNH2BH3 (R = -CH3, -CH2-) with AIX(3) salts (X = BH4-, Cr-), aiming to extend the series to different anions and to enlarge the stability window for Al(BH4)(3)center dot NRBH. Three novel complexes were identified: Al(BH4)(3)center dot CH3NH2BH3 having a molecular structure similar to that of Al(BH4)(3)center dot AB but different dehydrogenation properties, as well as [Al(CH3NH2BH3)(2)Cl-2] [AlCl4] and [Al(NH2CH2CH2NH2) (BH4)(2)] [Al-(BH4)(4)], rare examples of Al3+ making part of the cations and anions simultaneously. The latter compounds are of interest in the design of novel electrolytes for Al-based batteries. The coordination of two ABs to a single Al atom opens a route to materials with higher hydrogen content.