253183-71-0Relevant articles and documents
Intramolecular Electron Transfer from Mn or Ligand Phenolate to Photochemically Generated RuIII in Multinuclear Ru/Mn Complexes. Laser Flash Photolysis and EPR Studies on Photosystem II Models
Burdinski, Dirk,Wieghardt, Karl,Steenken, Steen
, p. 10781 - 10787 (2007/10/03)
In a mononuclear MnIV and a trinuclear MnII complex, the ligands of which contain electron-rich phenols (coordinated to the Mn('s)) and covalently attached ruthenium(II) 2,2′-trisbipyridyl(=bpy)-type groups, intramolecular electron transfer (ET) from the phenolate ligand (in the mononuclear MnIV complex) or from a MnII (in the trinuclear MnII complex) to the photochemically (λexc= 455 nm) generated RuIII takes place with k ≥ 5 × 107 s-1, giving rise to the corresponding phenoxyl radical (complexed to MnIV) or to MnIII, respectively. Thus, in the trinuclear MnII complex, the source of the electron that reduces the photogenerated RuIII(bpy?-) moiety is a MnII, in contrast to the situation with the mononuclear MnIV complex, where the electron stems from a phenolate. The half-life of the coordinated phenoxyl-type Ru(bpy)/Mn complex (as produced in the presence of [CoIII(NH3)5Cl]2+) is of the order 0.5-1 ms. The Ru(bpy) compound containing three (phenolate-ligated) MnII atoms is the first example of a photochemically induced intramolecular ET from a multinuclear Mn cluster to an attached sensitizer , and the Ru complex containing one (phenolate-ligated) MnIV is the first case of an ET from a synthetic MnIV-coordinated phenolate to a photochemically produced oxidant (RuIII).
