One-pot synthesis and characterization of a chromophore-donor-acceptor assembly

The acid-functionalized tris-heteroleptic chromophore-donor-acceptor assembly [Ru-II(bpyCOOH)(bpyCH(2)PTZ)(bpyCH(2)MV(2+))](PF6)(4)](4+) (1) (bpyCOOH = 4'-methyl-2,2'-bipyridine-4-carboxylic acid; bpyCH(2)PTZ = 10-((4'-methyl-2,2'-bipyridin-4-yl)methyl)phenothiazine; bpyCH(2)MV(2+) = 1-((4'-methyl-2,2'-bipyridin-4-yl)methyl)1'-methyl-4,4'-bipyridinediium) was synthesized in a one-pot reaction by careful selection of the order of ligand addition to RuCl2(DMSO)(4) (DMSO = dimethyl sulfoxide). The success of this method was based upon separation and isolation of 1 from mixtures containing ligand-scrambled products by cation exchange chromatography. Metal-to-ligand charge-transfer (MLCT) excitation in acetonitrile at 464 nm was followed by intramolecular electron transfer to give a redox-separated state [Ru-II(bpyCOOH)(bpyCH(2)PTZ(.+))(bpyCH(2)MV(.+))](4+) with an efficiency of eta(RS) = 0.35 +/- 0.05.