Intramolecular effects electron-transfer reactions

While being very similar in the general description, the RLT and electron-transfer processes differ in the vibration types they involve. In the first case, those are the high-frequency intramolecular modes, while in the second case the major role is played by the continuous spectrum of polarization phonons in condensed 3D media [Dogonadze and Kuznetsov 1975]. The localization effects mentioned in the previous section, connected with the low-frequency part of the phonon spectrum, still do not show up in electron-transfer reactions because of the asymmetry of the potential. 

Yonemura, H., Noda, M., Hayashi, K, Tokudome, H., Moribe, S. andYamada, S. (2002) Photoinduced intramolecular electron transfer reactions in fiillerene-phenothiazine linked compounds effects of magnetic field and spacer chain length. Mol. Phys., 100, 1395-1403. 

The interconversion between different spin states is closely related to the intersystem crossing process in excited states of transition-metal complexes. Hence, much of the interest in the rates of spin-state transitions arises from their relevance to a better understanding of intersystem crossing phenomena. The spin-state change can alternatively be described as an intramolecular electron transfer reaction [34], Therefore, rates of spin-state transitions may be employed to assess the effect of spin multiplicity changes on electron transfer rates. These aspects have been covered in some detail elsewhere [30]. 

An expression of the type in Eq. (29) has been rederived recently in Ref. 13 for outer-sphere electron transfer reactions with unchanged intramolecular structure of the complexes where essentially the following expression for the effective outer-sphere reorganization energy Ers was used ... 

Electrochemical oxidation of some catecholamines such as dopamine, L-dopa, and methyldopa has been studied using cyclic voltammetry. The catecholamines undergo intramolecular cyclization to form the corresponding o-quinone derivatives. The significant differences in the electrochemical behaviour of the catecholamines have been attributed to the effects of the side-chain carboxyl group.253 Electron-transfer reactions of 2,-deoxyguanosine-5,-monophosphate (dGMP) in phosphate buffers by cyclic... 

Scott JR, Fairris JL, McLean M, et al. Intramolecular electron-transfer reactions of cytochrome 5 covalently bonded to ruthenium(II) polypyridine complexes reorgani-zational energy and pressure effects. Inorg Chim Acta 1996 243 193-200. 

Effective molarities of intramolecular reactions, 17, 183 Electrical conduction in organic solids, 16, 159 Electrochemical methods, study of reactive intermediates by, 19, 131 Electrochemistry, organic, structure and mechanism in, 12, 1 Electrode processes, physical parameters for the control of, 10, 155 Electron spin resonance, identification of organic free radicals by, 1, 284 Electron spin resonance studies of short-lived organic radicals, 5, 23 Electron-transfer reaction, free radical chain processes in aliphatic systems involving an, 23, 271... 

To distinguish between paths A and B in Scheme 2, Dinnocenzo and coworkers [78-80] determined intramolecular isotope effects for deprotonation from the radical cations (path A) and for hydrogen-atom abstraction from a series of substituted 7V,A-dimethylanilines (path B) these were compared with isotope effects for N-demethylation of the same series of 7V,7V-dimethylanilines. The deprotonation iso-tope-effect profile for the radical cations of A, iV-dimethylanilines were determined by monitoring electron-transfer reactions from A, A -dimethylanilines to [Fe(phen)3] ... 

Electron Transfer Reactions and Exciolexes - Photoinduced electron transfer is one of the most important areas of research. A review of photoinduced electron transfer and electron acceptor complexes usefully surveys the subject . Details of the mechanisms can be obtained by very short time resolution spectroscopy. Dynamic solvent effects on intramolecular electron-transfer involve solvent fluctuations. Time resolved ps emission spectroscopy has been used to examine the kinetics of intramolecular charge transfer in bis(4-aminophenyl)sulphone in ethanol as a function of temperature in this respect 2. it has... 

Related molecular dyads have been constructed in which a metal complex, often ruthenium(II) tris(2,2 -bipyridine) or similar, functions as chromophore and an appended organic moiety acts as redox partner. Other systems " have been built from two separate metal complexes. Each of these systems shows selective intramolecular electron transfer under illumination. Rates of charge separation and recombination have been measured in each case and, on the basis of transient spectroscopic studies, the reaction mechanism has been elucidated. The results are of extreme importance for furthering our understanding of electron-transfer reactions and for developing effective molecular-scale electronic devices. The field is open and still highly active. 

Sumi H. and Marcus R. A. (1986), Dielectric relaxation and intramolecular electron transfers and Dynamical effects in electron transfer reactions , J. Chem. Phys. 84, 4272-4276 and 4894-4914. 

Electron-Transfer Reactions. It is well known that thermal and photochemical electron-transfer reactions exhibit characteristic pressure dependences and associated volumes of activation (see Sections II, III, and VI). It is therefore realistic to expect that photoinduced thermal electron-transfer reactions will also exhibit a characteristic pressure dependence that should reveal mechanistic information on the nature of the reaction. Recent interest in the mechanistic understanding of long-distance electron-transfer reactions prompted an investigation of the effect of pressure on intramolecular electron transfer in ruthenium-modified cytochrome c [151] (a typical example of a closely related intermolecular electron-transfer reaction was... 

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