Geometry Optimisations

Theoretical calculations were carried out in Gaussian16. All geometry optimisations and frequency calculations were performed in the density functional theory (DFT) framework using the hybrid exchange−correlation PBE0 functional together with the GD3BJ version of Grimme’s dispersion correction and the split-valence Pople’s 6-31G(d,p) basis set. All geometry optimisations were carried out in gas phase until convergence, followed by a frequency calculation in order to ensure a true local minimum on the potential energy surface (PES) was achieved.