| 1. |
- Fryxelius, J., et al.
(författare)
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Synthesis and redox properties of a meso-tris(4-nitrophenyl) corrolato Mn(III) complex
- 2005
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Ingår i: Journal of Porphyrins and Phthalocyanines. - 1088-4246 .- 1099-1409. ; 9:6, s. 379-386
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Tidskriftsartikel (refereegranskat)abstract
- The Mn complexated corrole [T(4-NO2P)Corr]Mn(py) (3) has been prepared (py = pyridine) where [T(4-NO2P)Corr] is the trianion of the electron-poor 5,10,15-tris(4-nitrophenyl)-corrole (1). The preparation of 3 includes a new synthetic method to form the corrole ligand 1 in a two-step synthesis. The Mn(III) complex gives a parallel mode EPR signal centered around g = 8.2 with six distinct hyperfine lines (A(parallel to) = 139 x 10(-4) cm(-1)). Electrochemically 3 undergoes one reversible oxidation (E-1/2 = 0.12 V vs Fc) and two reversible reductions (E-1/2 = -1.45, -1.61 V). The oxidation is metal-centered and the product has been characterized by EPR spectroscopy as an S = 3/2 Mn(IV) species with no indication for oxidation of the macrocycle. The reductions of complex 3 are ligand based, and at the potential of the second reduction step a stable nitrogen centered radical with g = 2.0055 is generated. Chemical oxidation of 3 by iodosobenzene yields a Mn(IV) complex and epoxidation of cis-stilbene is not catalyzed by the Mn complex.
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| 2. |
- Pan, Jingxi, et al.
(författare)
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Stepwise charge separation from a ruthenium-tyrosine complex to a nanocrystalline TiO2 film
- 2004
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:34, s. 12904-12910
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Tidskriftsartikel (refereegranskat)abstract
- A supramolecular complex composed of Ru(II) tris-bipyridine, tyrosine, and dipicolylamine was synthesized and characterized. This complex was attached to TiO2 nanocrystalline films via ester groups at the Ru(II) chromophore, and photoinduced multistep electron transfer was investigated by laser flash photolysis and electron paramagnetic resonance techniques. Following ultrafast electron injection from the metal-ligand charge transfer excited states of Ru(II) to the conduction band of TiO2, fast intramolecular electron transfer from the tyrosine moiety to the photogenerated Ru(III) was observed, characterized by a rate constant of similar to2 x 10(6) s(-1). By comparison of recovery kinetics at the isosbestic point with that of the reference compound lacking the tyrosine, it was found that the intramolecular electron-transfer efficiency is 90%. A hydrogen-bond-promoted electron-transfer mechanism is proposed.
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