Electron transfer reactions coordination compounds

Electron Transfer in Coordination Compounds Electron Transfer Reactions Theory. 

The majority of organometallic complexes contain 18 electrons see Bonding Energetics of Organometallic Compounds). These complexes undergo ligand substitution, reductive elimination, and electron-transfer reactions see Electron Transfer in Coordination Compounds). Each type of reaction will be covered in the following sections. 

An organometallic radical may undergo several different types of reactions Scheme 3 illustrates some different reactions of CpM(CO)3 radicals (21) including (i) dimerization (ii) halide abstraction from an alkyl hahde or metal halide (iii) hydrogen atom abstraction from metal hydrides (iv) electron-transfer reduction (v) electron-transfer oxidation and ligand addition (vi) electron-transfer induced disproportionation (see Electron Transfer in Coordination Compounds). 

Asymmetric Synthesis by Homogeneous Catalysis Coordination Chemistry History Coordination Organometallic Chemistry Principles Dihydrogen Complexes Related Sigma Complexes Electron Transfer in Coordination Compounds Electron Transfer Reactions Theory Heterogeneous Catalysis by Metals Hydride Complexes of the Transition Metals Euminescence Luminescence Behavior Photochemistry of Organotransition Metal Compounds Photochemistry of Transition Metal Complexes Ruthenium Organometallic Chemistry. 

The nse of polysnlfide complexes in catalysis has been discnssed. Two major classes of reactions are apparent (1) hydrogen activation and (2) electron transfers. For example, [CpMo(S)(SH)]2 catalyzes the conversion of nitrobenzene to aniline at room temperature, while (CpMo(S))2S2CH2 catalyzes a number of reactions snch as the conversion of bromoethylbenzene to ethylbenzene and the rednction of acetyl chloride, as well as the rednction of alkynes to the corresponding cw-alkenes. Electron transfer reactions see Electron Transfer in Coordination Compounds) have been studied because of their relevance to biological processes (in, for example, ferrodoxins), and these cluster compounds are dealt with in Iron-Sulfur Proteins. Other studies include the use of metal polysulfide complexes as catalysts for the photolytic reduction of water by THF and copper compounds for the hydration of acetylene to acetaldehyde. ... 

Copper Proteins with Type 1 Sites Cytochrome Oxidase Electron Transfer in Coordination Compounds Electron Transfer Reactions Theory Iron Heme Proteins Electron Transport Iron Heme Proteins, Peroxidases, Catalases Catalase-peroxidases Photosynthesis. 

Electron-transfer reactions see Electron Transfer in Coordination Compound are important because (3) behaves as a better oxidizing and reducing agent than (1). 

Outer-sphere electron transfer reactions involving the [Co(NH3)6]3+/2+ couple have been thoroughly studied. A corrected [Co(NH3)6]3+/2+ self-exchange electron transfer rate (8 x 10-6M-1s-1 for the triflate salt) has also been reported,588 which is considerably faster than an earlier report. A variety of [Co(NH3)g]3+/2+ electron transfer cross reactions with simple coordination compounds,589 organic radicals,590,591 metalloproteins,592 and positronium particles (electron/ positron pairs)593 as redox partners have been reported. 

Several classes of coordination compound undergo several successive, reversible one-electron-transfer reactions. These comprise a so-called electron-transfer chain or series .8 Cyclic voltammetry is particularly useful for recognizing such behaviour and an example is illustrated by Figure 2. This shows the four members of the electron-transfer chain [Fe4S4(SPh)4]"-, n = 1-4.5 An electron-transfer series provides the coordination chemist with a means of examining the consequence of systematic addition (or removal) of electrons from a nominally fixed geometry thermodynamic, kinetic and spectroscopic relationships between members of a series can be explored.9... 

A single electron-transfer reaction of a coordination compound may result in the generation of an unstable or reactive species which decays to a more stable product, i.e. the primary species generated by electron transfer undergoes further chemistry. 

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