In addition, we have performed Natural Population Analysis (NPA) to evaluate the charge on the RE cations after complexation with PF6 -anions, i.e., in [Ln(PF6)n] 3-n complexes using the JANPA software package. The Non-Covalent Interaction (NCI) plot analyses have been performed to visualize the non-covalent interactions present in the [Ln(PF6)x(MMI)(x-3)] complexes and represented using the VMD visualization software. The green iso-surface indicates the attraction between the moieties.