Electron-Transfer and Redox Reactivity of High-Valent Iron Imido and Oxo Complexes with the Formal Oxidation States of Five and Six

2020 ◽  
Vol 142 (8) ◽  
pp. 3891-3904 ◽  
Author(s):  
Xiaoyan Lu ◽  
Xiao-Xi Li ◽  
Yong-Min Lee ◽  
Yuri Jang ◽  
Mi Sook Seo ◽  
...  
2015 ◽  
Vol 44 (15) ◽  
pp. 6696-6705 ◽  
Author(s):  
Shunichi Fukuzumi

High-valent metal-oxo complexes are produced by thermal and photoinduced electron-transfer reactions, acting as catalysts for oxygenation of substrates using water or dioxygen as an oxygen source.


1992 ◽  
Vol 57 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Pavel Lederer ◽  
Galina V. Nizova ◽  
Marina M. Kats ◽  
Georgii B. Shuľpin

Irradiation of cyclohexane solution in acetonitrile (λ = 300, 365, or 436 nm) in the presence of dioxygen and catalytic amounts of FeCl3, CuCl3, Na[AuCl4] or H2[PtCl]6 gives rise to cyclohexanol and cyclohexanone (after GLC). The quantum yields with respect to the products lie within the range of 0.01 to 0.05. The most efficient of the catalysts used is FeCl3, and the most efficient radiation wavelength is λ = 365 nm. A reaction pathway is suggested; it is assumed that the first step is photoexcitation of M-Cl followed by electron transfer from the ligand to the metal associated with the formation of the Cl. radical, which reacts (probably after solvation by the solvent) with RH giving R.. The Fe(II) species is oxidized by ROO., and the photocatalytically active complex is restored. Complexes with metals in low oxidation states (particularly in the case of Cu, Au and Pt), however, can react with molecular oxygen to give peroxo or oxo complexes, which can directly hydroxylate alkanes.


2018 ◽  
Vol 57 (22) ◽  
pp. 14401-14408 ◽  
Author(s):  
Delina Damatov ◽  
Stephanie M. Laga ◽  
Elizabeth A. Mader ◽  
Jing Peng ◽  
Rishi G. Agarwal ◽  
...  

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 610
Author(s):  
Magdalena Procner ◽  
Łukasz Orzel ◽  
Grażyna Stochel ◽  
Rudi van Eldik

New, more efficient methods of wastewater treatment, which will limit the harmful effects of textile dyes on the natural environment, are still being sought. Significant research work suggests that catalysts based on transition metal complexes can be used in efficient and environmentally friendly processes. In this context, a number of compounds containing manganese have been investigated. A suitable catalyst should have the capacity to activate a selected oxidant or group of oxidants, in order to be used in industrial oxidation reactions. In the present study we investigated the ability of MnIII(TPPS), where TPPS = 5,10,15,20-tetrakis(4-sulphonatophenyl)-21H,23H-porphyrine, to activate five different oxidants, namely hydrogen peroxide, peracetic acid, sodium hypochlorite, potassium peroxomonosulfate and sodium perborate, via the formation of high valent Mn(TPPS)-oxo complexes. Kinetic and spectroscopic data showed that the oxidation process is highly pH dependent and is strongly accelerated by the presence of carbonate in the reaction mixture for three of the five oxidizing agents. The highest efficiency for the oxidation of MnIII(TPPS) to high-valent Mn(TPPS)-oxo complexes, was found for peracetic acid at pH ≈ 11 in 0.5 M carbonate solution, which is at least an order of magnitude higher than the rate constants found for the other tested oxidants under similar conditions.


1982 ◽  
Vol 37 (3) ◽  
pp. 324-331 ◽  
Author(s):  
Heindirk torn Dieck ◽  
Ewald Kühl

Abstract Carbonyl complexes of chromium, molybdenum and tungsten of the type DAD M(CO)4 with DAD - diazadiene (R-N=CR′-CR′=NR) are shown by cyclic voltammetry to undergo electron transfer reactions to [DAD M(CO)4]+ and [DAD M(CO)4]-. The rate of subsequent chemical reactions with nucleophiles or by loss of ligands depend on the sol-vent, the metal and the ligands' electronic and steric properties. Chromium(+I) is more readily stabilized than Mo(+I) or W(-I) while the opposite is true for the stability of the anions formed. The dimerisation of a low-coordinate species DAD Mo(CO)3 from the reduction of DAD Mo(CO)3(CH3CN) is detected electrochemically. The stabilization of oxidation states +1 and -I is briefly discussed in view of the DAD ligand properties.


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