Efficient Synthesis of an Aluminum Amidoborane Ammoniate

A novel species of metal amidoborane ammoniate, [Al(NH2BH3)(6)(3-)][Al(NH3)(6)(3+)] has been successfully synthesized in up to 95% via the one-step reaction of AlH3OEt2 with liquid NH(3)BH(3)nNH(3) (n = 1 similar to 6) at 0 degrees C. This solution based reaction method provides an alternative pathway to the traditional mechano-chemical ball milling methods, avoiding possible decomposition. MAS Al-27 NMR spectroscopy confirms the formulation of the compound as an Al(NH2BH3)(6)(3-) complex anion and an Al(NH3)(6)(3+) cation. Initial dehydrogenation studies of this aluminum based M-N-B-H compound demonstrate that hydrogen is released at temperatures as low as 65 degrees C, totaling similar to 8.6 equivalents of H-2 (10.3 wt %) upon heating to 105 degrees C. This method of synthesis offers a promising route towards the large scale production of metal amidoborane ammoniate moieties.