Lithiated primary amine--a new material for hydrogen storage.

A facile method for synthesizing crystalline lithiated amines by ball milling primary amines with LiH was developed. The lithiated amines exhibit an unprecedented endothermic dehydrogenation feature in the temperature range of 150-250 °C, which shows potential as a new type of hydrogen storage material. Structural analysis and mechanistic studies on lithiated ethylenediamine (Li2EDA) indicates that Li may mediate the dehydrogenation through an α,ß-LiH elimination mechanism, creating a more energy favorable pathway for the selective H2 release.

Role of NH3 in the dehydrogenation of calcium amidoborane ammoniate and magnesium amidoborane ammoniate: a first-principles study.

First-principles calculations show that [NH(3)] molecules play crucial roles as both activator for the break-up of B-H bond and supplier of protic H for the establishment of dihydrogen bonding, which could facilitate the dehydrogenation of Ca(NH(2)BH(3))(2)·2NH(3) or Mg(NH(2)BH(3))(2)·NH(3) occurring at lower temperatures compared to those of Ca(NH(2)BH(3))(2) and Mg(NH(2)BH(3))(2). Moreover, the calculations of Helmholtz Free energy and [NH(3)] molecule removal energy evidence that coordination between [NH(3)] and Mg cation is stronger than that between [NH(3)] and Ca cation; therefore, Mg(NH(2)BH(3))(2)·NH(3) will undergo directly dehydrogenation rather than deammoniation at lower temperatures.

Interaction of ammonia borane with Li2NH and Li3N.

Interaction of NH(3)BH(3) and Li(2)NH (or Li(3)N) in THF leads to the formation of NH(3) and LiNH(2)BH(3), which further react with each other and produce ca. 10 wt.% hydrogen at 45 degrees C.