Emissive cyanide-bridged bimetallic compounds as building blocks for polymeric antennae

摘要

A series of cyanide-bridged bimetallic compounds of the general formula [Ru(L)(bpy)(μ-NC)(M)]~(2-/-/2+) (L = tpy, 2,2′-6′, 2′′-terpyridine, or tpm, tris(1-pyrazolyl)methane, bpy = 2,2′-bipyridine, M = Ru~(II)(CN)_5, Os ~(III)(CN)_5, Os~(II)(CN)_5, Ru ~(II)(py)_4(CN), py = pyridine) have been synthesized and fully characterized. Most of them present MLCT emission (λ = 690-730 nm, Φ = 10~(-3)-10~(-4)) and their photophysical properties resemble the ones of the respective mononuclear Ru(L)(bpy) species. The exception is when M is Os~(III)(CN)_5, where an intramolecular electron transfer quenching mechanism is proposed. The conditions that should be met for avoiding the reductive or oxidative quenching of the excited state are also discussed.