Fig. 1. (a) Structure of the [Cu(POP)(5,5′-Me₂bpy)]⁺ cation with ellipsoids plotted at 50% probability, H atoms are omitted for clarity. Face to face π-stacking between the phenyl ring containing C15 and the ring of the POP backbone at P2 (angle between the ring planes 13.94°, centroid–centroid distance 3.641 Å). (b) Structure of the [Cu(xantphos)(5,5′-Me₂bpy)]⁺ cation with ellipsoids plotted at 50% probability, H atoms are omitted for clarity. Weak π-interaction between two of the phenyl rings on each P atom (involving C23 and C46, respectively) (angle between the ring planes 21.65°, centroid–centroid distance 3.843 Å) and no intramolecular π-interaction involving the xanthene backbone.