A dinuclear Ru(II) complex capable of photoinduced ligand exchange at both metal centers

{[Ru(CH3CN)3]2(tppz)}4+ (tppz = tetra-2-pyridylpyrazine) undergoes photoinduced CH3CN exchange with λirr ≥ 610 nm in H2O. In contrast, cis-{[Ru(tpy)(L)]2(bpm)}4+ (tpy = 2,2′:6′,2′′-terpyridine, bpm = 2,2′-bipyrimidine, L = CH3CN) is not reactive, but the complex with L = DMSO is photoactive. These complexes are potentially useful for the release of multiply caged drugs.