The Tunable Luminescence of Ruthenium(II) Complexes Containing Different Tetrazolate Ligands

Three luminescent mononuclear RuII compounds, [RuII(bpy)2(L1)](BF4) (1), [RuII(bpy)2(L2)](BF4) (2), and the neutral compound [RuII(bpy)2(L3)] (3), were obtained, by treatment of [RuII(bpy)2Cl2] with the tetrazolate (tz)‐containing ligands L1–L3. All the compounds were well characterized by IR, UV/Vis, and 1H NMR and their redox properties were also investigated by cyclic voltammogram. The crystal structure of 3 was determined by X‐ray crystallography and it clearly shows that the RuII ion is octahedrally coordinated by two bpy ligands and a deprotonated L3 ligand. After introduction of these tz ligands, 1–3 are more sensitive towards the change of micro‐environment of solvents as compared with that of [RuII(bpy)3]2+. This effect is most obvious in 3, since it contains a 2– ligand L3. The slight modification of diimine ligand make these complexes have potential applications as sensors.