The computed total energy of the precursor molecule and a free ligand are denoted by EP and EL respectively, while the To understand the experimental results regarding reactivity, we consider the energetics of ligand elimination from each precursor. The computed energies for elimination of H by breaking the Al-H bond are 137.42 kJ mol -1 , 136.37 kJ mol -1 and 132.58 kJ mol for AlH3:NMe3, Al(DMP)HCl and Al(Me2NEtN t Bu)H2 respectively. These are relatively low energies, essentially identical across all Al-hydrides, suggesting facile loss of H from each precursor. Considering AlH3:NMe3 (4), the energy required to eliminate NMe3 through breaking the Al-N bond is 125.92 kJ mol showing, as expected from the structure of the complex, a weaker bond is present between Al and N, which is more favourable to dissociate compared to the Al-H bond. This is consistent with the abundance of [NMe3] + found in the mass spectrometry data (table ).