Intense Red‐Blue Luminescence Based on Superfine Control of Metal–Metal Interactions for Self‐Assembled Platinum(II) Complexes

A series of assembled Pt II complexes comprising N‐heterocyclic carbene and cyanide ligands was constructed using different substituent groups, [Pt(CN) 2 (R‐impy)] (R‐impyH + =1‐alkyl‐3‐(2‐pyridyl)‐1 H ‐imidazolium, R=Me ( Pt‐Me ), Et ( Pt‐Et ), i Pr ( Pt‐ i Pr ), and t Bu ( Pt‐ t Bu )). All the complexes exhibited highly efficient photoluminescence with an emission quantum yield of 0.51–0.81 in the solid state at room temperature, originating from the triplet metal‐metal‐to‐ligand charge transfer ( 3 MMLCT) state. Their emission colors cover the entire visible region from red for Pt‐Me to blue for Pt‐ t Bu . Importantly, Pt‐ t Bu is the first example that exhibits blue 3 MMLCT emission. The 3 MMLCT emission was proved and characterized based on the temperature dependences of the crystal structures and emission properties. The wide‐range color tuning of luminescence using the 3 MMLCT emission presents a new strategy of superfine control of the emission color.