Electron oxidation activation

Subsequent studies (63,64) suggested that the nature of the chemical activation process was a one-electron oxidation of the fluorescer by (27) followed by decomposition of the dioxetanedione radical anion to a carbon dioxide radical anion. Back electron transfer to the radical cation of the fluorescer produced the excited state which emitted the luminescence characteristic of the fluorescent state of the emitter. The chemical activation mechanism was patterned after the CIEEL mechanism proposed for dioxetanones and dioxetanes discussed earher (65). Additional support for the CIEEL mechanism, was furnished by demonstration (66) that a linear correlation existed between the singlet excitation energy of the fluorescer and the chemiluminescence intensity which had been shown earher with dimethyl dioxetanone (67). 

Polymerization Initiator. Some unsaturated monomers can be polymerized through the aid of free radicals generated, as transient intermediates, in the course of a redox reaction. The electron-transfer step during the redox process causes the scission of an intermediate to produce an active free radical. The ceric ion, Ce" ", is a strong one-electron oxidizing agent that can readily initiate the redox polymerization of, for example, vinyl monomers in aqueous media at near ambient temperatures (40). The reaction scheme is... 

There is much evidence to suggest that carcinogenic N-nitros-amines are metabolised by an oxidative process to produce an alkylating agent (J f2) One potential metabolite is therefore the corresponding N-nitrosamide resulting from 2-electron oxidation at the oc-carbon atom, and, indeed, such compounds appear to induce tumours at the site of application without metabolic activation (3) It follows that the chemical properties of N-nitrosamides are relevant to the etiology of cancer ... 

Cremonesi P, EL Cavalieri, EG Rogan (1989) One-electron oxidation of 6-substituted benzo(a)pyrenes by manganic acetate. A model for metabolic activation. J Org Chem 54 3561-3570. 

Recent studies [193] of the CO oxidation activity exhibited by highly dispersed nano-gold (Au) catalysts have reached the following conclusions (a) bilayer structures of Au are critical (b) a strong interaction between Au and the support leads to wetting and electron rich Au (c) oxidative environments deactivate Au catalyst by re-ox-idizing the support, which causes the Au to de-wet and sinter. Recent results have shown that the direct intervention of the support is not necessary to facilitate the CO oxidation reaction therefore, an Au-only mechanism is sufficient to explain the reaction kinetics. 

Many of the problems and misconceptions occurring for dithiolene compounds are related to the fact that the ligands are redox-active and can be oxidized to monoanionic radicals. Typical examples for this phenomenon are the mono and diradical complexes [Fe ( "bdt )( "bdt)(PMe3)] (9) and [Fe ( "bdf)2(PMe3)]-" (10) for which bdt and bdt are tcrt-butyl-dithiolene and its one-electron oxidized form. Originally, these and other bdt derivatives had been described as... 

The enzymatic reactions of peroxidases and oxygenases involve a two-electron oxidation of iron(III) and the formation of highly reactive [Fe O] " species with a formal oxidation state of +V. Direct (spectroscopic) evidence of the formation of a genuine iron(V) compound is elusive because of the short life times of the reactive intermediates [173, 174]. These species have been safely inferred from enzymatic considerations as the active oxidants for several oxidation reactions catalyzed by nonheme iron centers with innocent, that is, redox-inactive, ligands [175]. This conclusion is different from those known for heme peroxidases and oxygenases... 

The one-step reaction of H2prCl6] with MeC02Li under 02 in a mixed solvent of acetic acid and acetic anhydride yields the Ir11 binuclear complex [Ir2(/u-02CMe)2Cl2(C0)2].483 Crystal-structure determinations of [Ir2(/x-02CMe)2Cl2(C0)2L2], (295), where L = MeCN, DMSO, and py, are reported. The one-electron oxidation product for (295), L = py, is EPR active at 77 K the odd electron occupies the 6Ir Ir orbital. 

Copper(II) complexes with phenoxo ligands have attracted great interest, in order to develop basic coordination chemistry for their possible use as models for tyrosinase activity (dimeric complexes) and fungal enzyme galactose oxidase (GO) (monomeric complexes). The latter enzyme catalyzes the two-electron oxidation of primary alcohols with dioxygen to yield aldehyde and... 

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