Optical sensing properties of [Ru(CN)4dppz]2− (dppz=dipyrido[3,2-a:2′,3′-c]phenazine)

[Ru(CN)4dppz]2− (dppz=dipyrido[3,2-a:2′,3′-c]phenazine) can be synthesized photochemically from [Ru(CN)6]4− and dppz, albeit in low yield with competing side reactions. The complex’s absorption maximum in various solvents track the solvent Lewis acidity as judged by Gutmann’s acceptor number. At room temperature, [Ru(CN)4dppz]2− emits weak green light in ethanol that resembles that of the free dppz ligand; at 77 K, [Ru(CN)4dppz]2− emits brightly in the red. Prospects for using [Ru(CN)4dppz]2− in sensor applications are discussed.