Luminescent pH sensors based on di(2,2′-bipyridyl)(5,5′-diaminomethyl-2,2′-bipyridyl)-ruthenium( II ) complexes

Luminescent pH sensors based on [RuII(bpy)3]2+(bpy = 2,2′-bipyridyl) display proton assisted retrieval of luminescence in 1b–d and proton assisted quenching of luminescence in 1a(both due to photoinduced electron transfer) and proton promoted luminescence quenching due to the generation of positive charges in the vicinity of the [RuII(bpy)3]2+ luminophore in 1e–g probably leading to a Ru–N bond fission in the excited state.