A luminescent pH sensor based on a diruthenium(II) complex: `off–on–off' switching via the protonation/deprotonation of an imidazole-containing ligand

Abstract

Complex [(bpy) 2Ru(bpibH 2)Ru(bpy) 2](ClO 4) 4·3H 2O ( 1) (bpy=2,2′-bipyridine and bpibH 2=1,4-bis([1,10]phenanthroline[5,6- d]imidazol–2-yl)benzene), which contains two metallolumophores and a two receptor system, acts as an `off–on–off' luminescent pH sensor through protonation and deprotonation in MeOH–H 2O (1:1 v/v) solution at room temperature.