Perfluoroarenes Enhance, Perfluoroquinones Quench: Orbital Interaction Regimes Controlling Phosphorescence in Cyclometalated Pt ^II Complexes

Cyclometalated platinum(II) complexes exhibit opposite luminescent responses to different π-hole donors. While perfluoroarenes enhance phosphorescence through weak interactions, perfluoroquinones completely quench emission despite forming structurally similar cocrystals. X-ray crystallography shows that quinone adducts exhibit shorter Pt···centroid distances (3.382-3.412 vs 3.624-3.721 Å for perfluoroarenes) and multiple C···Pt tetrel bonds. Unlike yellow-green luminescent perfluoroarene systems, quinone adducts display characteristic brown coloration and new charge-transfer absorption bands at 575-578 nm. DFT calculations reveal that d_<i>z</i>²(Pt) → π*(quinone) orbital interactions contribute -6.8 kcal/mol (32% of orbital binding energy), creating efficient nonradiative deactivation pathways absent in perfluoroarene systems. Natural transition orbital analysis confirms intermolecular charge transfer in quinone adducts versus localized excitations in arene systems, explaining the complete luminescence quenching despite structural similarities. This work establishes perfluoroquinones as a new class of luminescence modulators, demonstrating that electronic coupling strength determines whether π-hole interactions enhance or quench phosphorescence.