- Photoirradiated and γ-ray-irradiated reactions of manganese(III, IV, V) tetraphenylporphyrins in 2-methyltetrahydrofuran. Reactions of azidomanganese(III) porphyrin
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Manganese(III, IV) tetraphenylporphyrins MnIII(TPP)X (TPP = 5,10,15,20-tetraphenylporphinato; X = I, Br, Cl, N3, NCS, OAc) and MnIV(TPP)(OCH3)2 in 2-methyltetrahydrofuran (MeTHF) at room temperature were reduced to yield MnII(TPP) by photoirradiation with visible light (440-750 nm) or by γ-ray irradiation. The photoirradiation of MnIII(TPP)N3 in the rigid matrix at 77 K affords MnV(TPP)N. Photochemically stable MnV(TPP)N was reduced to MnII(TPP) by γ-irradiation at room temperature. γ-Irradiation of MeTHF solutions of MnIII(TPP)X at 77 K causes one-electron reduction to form the constrained complexes [MnII(TPP)X]-. Warming the matrices after γ-irradiation formed MnII(TPP), liberating ligand X-. The near-infrared bands of MnIII(TPP)X red shift along with the shifts of the bands in the visible region by varying the ligand X. The characteristic bands of the constrained complex [MnII(TPP)X]- in the near-infrared region red shift in the order X = Cl > Br > I. The photoirradiation of CrIII(TPP)N3 with visible light affords CrV(TPP)N at room temperature and at 77 K.
- Jin, Takashi,Suzuki, Toru,Imamura, Taira,Fujimoto, Masatoshi
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p. 1280 - 1285
(2008/10/08)
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- Oxochromium compounds. 2. Reaction of oxygen with chromium(II) and chromium(III) porphyrins and synthesis of a μ-oxo chromium porphyrin derivative
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The reaction of oxygen with Cr(II) porphyrin complexes in solution has been found to result in the formation of CrIVO(P) compounds when oxygen is in excess. Solid CrII(P) also react irreversibly with oxygen, and the products dissolve in toluene to form CrIVO(P). The complex (TPP)CrOCr(TPP) has been isolated from the reaction of CrO(TPP) and CrII(TPP) and shown to undergo further reaction with oxygen to give CrO(TPP). The complex shows an IR absorption at 860 cm-1, considered to indicate the presence of the CrOCr linkage, and has μeff = 1.61 μB per Cr at 300 K, indicating substantial antiferromagnetic coupling. Similar μ-oxo complex formation has been demonstrated spectroscopically between other CrO(P)/Cr(P′) combinations where P and P′ may be the same or different. (P)CrOCr(P) complexes can be detected as intermediates in the reaction of CrII(P) with oxygen when the amount of oxygen is restricted. CrIII(P)Cl also reacts with oxygen in chloroform in the presence of HCl to give intermediates that are converted to CrIVO(P) in the presence of basic alumina. A Cr-porphyrin π-cation radical is proposed as the intermediate.
- Liston, David J.,West, Bruce O.
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p. 1568 - 1576
(2008/10/08)
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- The Autoxidation of a Chromium(II) Porphyrin: Synthesis and Structural Characterisation by X-Ray Crystallography of αβγδ-Tetraphenylporphinato-oxochromium(IV)
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The reaction of dioxygen with αβγδ-tetraphenylporphinatochromium(II) in toluene proceeds in two stages; a μ-oxo-chromium(III) intermediate is formed initially and this then further reacts with dioxygen to give the title complex, the structure of which has been determined by X-ray crystallography.
- Budge, John R.,Gatehouse, Bryan M. K.,Nesbit, Michael C.,West, Bruce O.
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p. 370 - 371
(2007/10/02)
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