One-electron Oxidation Reactions Research Articles

Electrochemical studies of tris(acetylacetonato)ruthenium(III) in ambient-temperature chloroaluminate molten salts

The electrochemical properties of tris(8-diketonato) complexes involving many kinds of trivalent metal (e.g. chromi~m,~-~ mangane~e,*+~~~~ ’ iron2,3J.6*8-10 cobalt,2q3.6*11 ruthenium,l2-I6 and osmium,” etc.) have been studied in various protic and aprotic organic solvents. Most of these complexes undergo simple oneelectron reduction and/or one-electron oxidation reactions. The use of (8-diketonato)metal complexes in photoinduced electrontransfer reactions has enhanced the interest in the electrochemical properties of these compounds.17 Recently, studies of the electrochemistry and chemistry of tris(~diketonato)rthenate(II) and

Oxidation of 2-keto-4-thiomethylbutyric acid (KTBA) by iron-binding compounds produced by the wood-decaying fungus Gloeophyllum trabeum

The ability of iron-binding compounds isolated from the brown-rot fungus Gloeophyllum trabeum to carry out one-electron oxidation reactions was established using a model substrate, 2- keto-4-thiomethylbutyric acid (KTBA). The oxidation reaction was monitored by measuring the amount of ethylene produced from the substrate by gas chromatography. The extent of the reaction was found to be influenced by the concentration of the chelators, and by iron and manganese.

Oxidation of 2-keto-4-thiomethylbutyric acid (KTBA) by iron-binding compounds produced by the wood-decaying fungusGloeophyllum trabeum

The ability of iron-binding compounds isolated from the brown-rot fungus Gloeophyllum trabeum to carry out one-electron oxidation reactions was established using a model substrate, 2-keto-4-thiomethylbutyric acid (KTBA). The oxidation reaction was monitored by measuring the amount of ethylene produced from the substrate by gas chromatography. The extent of the reaction was found to be influenced by the concentration of the chelators, and by iron and manganese.

Photoelectron Emission Study of Iron(II) and Cobalt(II) Complexes in Aqueous Solution. Reorganization Energies

Abstract The photoelectron emission threshold energies of FeII and CoII complexes in aqueous solutions have been determined. The values could be successfully used for obtaining the reorganization energies in the one-electron oxidation reaction of these complexes. The obtained reorganization energies were found to be correlated with the rate constants of the electron-self-exchange reactions of FeII/FeIII and CoII/CoIII.

Reactions of co-ordinated ligands. Part 45. Ligand displacement and oxidative reactions of the carbyne complex [Mo(CCH2But){P(OMe)3}2(η-C5H5)]; crystal and molecular structures of [Mo{η3-RNCC(CH2But)CNR}-(CNR)2(η-C5H5)](R = 2,6-Me2C6H3), [Mo(CCHBut)I{P(OMe)3}2(η-C5H5)], and [M o{C(CH2But)P(O)(OMe)2}{P(OMe)3}(η-C5H5)

Reaction of the carbyne complexes [M(CCH2R){P(OMe)3}2(η-C5H5)](M = Mo or W, R = But or Pri) with 2,6-xylyl isocyanide affords the complexes [M{η3-R′NCC(CH2But)CNR′}(CNR′)2(η-C5H5)](R′= 2,6-Me2C6H3), the molybdenum complex being identified by X-ray crystallography. In the 1,3-di-imino-substituted η3-allyl fragment the nitrogen atoms are bent back away from the allyl plane to subtend C–C–N angles of 135.2(9) and 133.1 (9)°. The central carbon atom of the allyl is also tilted away from the metal possibly due to intramolecular interactions. These complexes show temperature-dependent n.m.r. spectra which are discussed in terms of rotation about C–NR bonds and endo/exo isomerism. In attempting to understand the mechanism of formation of these complexes the solution 31P-{1H} n.m.r. spectra of the carbyne in the presence of free P(OMe)3 was studied. A DANTE pulse sequence suggested that dissociative loss of P(OMe)3 is not a rate-determining step in the reaction with isocyanide. The reaction of [Mo(CCH2But){P(OMe)3}2(η-C5H5)] with CO was also studied leading to loss of P(OMe)3, and formation of [Mo(CCH2But)-(CO){P(OMe)3}(η-C5H5)],[Mo(CCH2But)(CO)2(η-C5H5)], and [Mo{σ-CH(CO2Me)CH2But}-(CO)2{P(OMe)3}(η-C5H5)]. The mechanism of formation of these complexes is discussed. In addition the reaction of potential one-electron oxidants with [Mo(CCH2But){P(OMe)3}2(η-C5H5)] has been examined. Treatment with [4-FC6H4N2][BF4] affords the vinylidene complex [Mo(CCHBut)(N2C6H4Me-4){P(OMe)3}(η-C5H5)], whereas reaction with CF3l gives the X-ray crystallogra phically identified complexes [Mo(CCHBut)I{P(OMe)3}2(η-C5H5)] and [[graphic omitted]-(OMe)2}I{P(OMe)3}(η-C5H5)]. It is suggested that the latter complex is formed via the migration of a phosphonate group from molybdenum onto a carbyne carbon atom.

The reorganization energies in one-electron oxidation of ferrous complexes in aqueous solution

The photoelectron emission method was used to determine the reorganization free energy of nuclear coordinates in one-electron oxidation reactions. The experimental results for eight ferrous complexes, some of which have large organic ligands, in aqueous solution are in excellent agreement with the theoretical ones.

Hydrogen peroxide-supported oxidation of benzo [ a]pyrene by rat liver microsomal fractions

In the presence of liver microsomes from phenobarbital-pretreated rats, hydrogen peroxide oxidized benzo [ a]pyrene to a number of biologically significant products at a rate that was approximately 20 per cent as fast as that seen by us and others with NADPH and oxygen. As with NADPH-dependent reactions [J. Capdevila, R. W. Estabrook, and R. A. Prough, Archs. Biochem. Biophys. 200, 186 (1980)], the hydrogen peroxide-dependent reactions resulted in the production of relatively large quantities of dihydrodiols as metabolites. This was in marked contrast to the product distribution observed when cumene hydroperoxide was utilized as a cosubstrate (foregoing reference). The formation of the various organic-soluble metabolites was dependent on the presence of functional liver microsomal cytochrome P-450 in the reaction mixture. Approximately 48 per cent of the benzo[ a]pyrene metabolites, however, was observed to be bound to microsomal protein, and inhibition of cytochrome P-450 function, by metyrapone or N-octylamine did not affect the extent of covalent binding of the hydrocarbon to the microsomal protein. The differences noted during benzo[ a]pyrene metabolism using hydrogen peroxide strongly suggest that at least two distinct mechanisms exist to account for the oxidation of the hydrocarbon, i.e. epoxidation and one-electron oxidation reactions.

Differential radical cation stability from the cis- and trans- cyclodiphospha(III)azane derivatives

The electrochemical oxidation reactions of cis- and trans-1,3-di-isopropyl-2,4-bis(di-isopropylamino)-cyclodiphospha(III)azane isomers are quite different; only the trans-(1) isomer undergoes a one-electron oxidation reaction to produce a stable radical cation.

Oxidation of thiols and disulphides with the ammoniumyl radical-cation,+˙NH3: an e.s.r. investigation

E.s.r. spectroscopy has been employed to demonstrate that the reaction of +˙NH3(from TiIII and +NH3OH) with thiols (RSH) proceeds via the initial formation of thiyl radicals (RS·); these react further to give disulphides as well as oxygen-containing radicals RSO· and RSO2·, formed by a series of one-electron oxidation reactions, and both SO2–˙ and SO3–˙(which arise via sulphur dioxide formed in the decomposition of RSO2˙). Reaction with disulphides, which leads to the detection of sulphinyl radicals and disulphide-conjugated radicals, is thought to involve both radical-cations (RSSR+˙) and ammoniumyl adducts [RS([graphic omitted]H3)SR] whose further reactions have been described.

Chemical and electrochemical oxidative cleavage reactions of compounds of the type η 5-C 5H 5Fe(CO) 2R

Chemical and electrochemical one-electron oxidation reactions of η 5-C 5H 5Fe(CO) 2R (R = Me, PhCH 2, PhCH 2CH 2) in methylene chloride in the presence of added chloride ion yield η 5-C 5H 5Fe(CO) 2Cl and RCl, apparently via the 17 electron complexes, [η 5-C 5H 5Fe(CO) 2R] + and η 5-C 5H 5Fe(CO) 2.

Some one-electron oxidation reactions of biheteroorganic derivatives with Ge-Hg and Ge-Li groupings

4-Bromo-2,4,6-tri-tert-butylcyclohexadien-2,5-one and the 2,4,6-tri-tert-butylphenoxyl radical function as a one-electron oxidizing agent in reactions with biheteroorganic compounds that contain the Ge-Hg and Ge-Li bonds.

Transition-metal dithiolene complexes. Part XVI. π-Cyclopentadienyl manganese nitrosyl 1,1-dithiolene complexes

The syntheses of the 1,1-dithiolene complexes, [(π-C5H5)Mn(NO)S2C:X]–, [X = C(CN)·CO2Et, C(CN)·CO·NH2 and N·CN], and of [(π-C5H5)Mn(NO)S2C·NR2](R = Me or Et) are described. Both series of complexes undergo one-electron oxidation reactions which were detected voltammetrically, and the half-wave potentials were dependent on the nature of the sulphur ligand substituents. The NO stretching frequencies of the compounds were also dependent on the sulphur ligand substituents and on the overall charge on the complex. The existence of [(π-C5H5)Mn(NO)S2C·X]0 and of [(π-C5H5)Mn(NO)S2C·NR2]+ was confirmed by e.s.r. spectral studies and the g-tensors and ΔaMn‡ were significantly different from those obtained from the 1,2-dithiolene analogues, [(π-C5H5)Mn(NO)S2C2R2]0 and [Mn(π-C5H5)(NO)S2C6Cl4]0.