Novel theoretical studies of the dehydrogenation of LiBH₂NH ₃

It is believed that the dehydrogenation of LiNH₂BH₃ (LAB) proceeds through a combination of the decomposition of the LiBH ₂NH₃ (LBA) and LAB isomers. The dehydrogenation of LBA, an isomer of LAB, is discussed in this article. It is demonstrated that the loss of H₂ from LBA takes place in a two-step reaction. Studies of the dehydrogenation process were performed using Møller-Plesset second-order perturbation theory with a 6-311++G(3df,2pd) basis set. The intrinsic reaction coordinate was calculated to determine the minimum energy paths. Finally, the rate constants were obtained using the transition-state theory (TST), TST/Eckart, canonical variational transition-state theory (CVT), CVT/small-curvature tunneling correction, and CVT/zero-curvature tunneling correction methods from 200 to 2500 K. This is the first report on a different dehydrogenation mechanism for an alkali-metal amidoborane, and the energy barrier of LBA is much lower than that of the traditionally studied LAB.