We then perform PBE single point energy evaluations on the 10 lowest GFN2-xTB energy structures and select the lowest PBE energy structure for geometry optimisation at the PBE level of theory. We noticed that xTB optimizations occasionally lead to the detachment of the N x H y moiety, and such structures tend to have higher energies at the PBE level and are thus discarded at this step. GFN2-xTB had been used to obtain low energy conformers in the conformer search, thus the conformers did likely not represent the lowest energy on the DFT surface. As such, the final lowest DFT SP energy conformers were passed to full DFT-PBE optimization in order to obtain the relaxed structures and thereby relaxed reaction energies at the DFT level.