As a complementary analysis tool to EA and NMR spectroscopy, FTIR was performed, as shown for three representative cases (2, 4 and 7) of each group of stabilized alanes (figure ). As the signal of aluminium bond hydrides in 1 H NMR often is significantly broadened due to coupling with the Al nucleus and thus may differ from expected values for the integration, or are not visible at all, FTIR can supplement compound characterization, as the Al-H bond gives a vibrational frequency signal in range of 1750 -1900 cm -1 . Same applies for the less stable compounds decomposing in solution (3, 8 and 9). The respective ν(Al-H) signals can be seen for all investigated compounds. The vibrational modes of the atomic structures of complexes 2, 4 and 7 can also be calculated using the aoforce program in TURBOMOLE. The Al-H vibrational modes are at 1788.93 cm -1 , 1830.32 cm -1 and 1770.01 cm -1 for AlH3:NMe3, Al(DMP)HCl and Al(Me2NEtN t Bu)H2 respectively which are all comparable to the experimental vibrational modes in figure .