Electron-transfer reactions INDEX

Cumulative Subject Index Single electron transfer reactions... 

CONTENTS Preface. Patrick S. Mariano. Recent Advances In Light-Induced Election Transfer Involving Inorganic Systems. Nick Serpone, Rita Terzian and Jean Marie Hermann. Photoinduced Electron Transfer in Dye-Polymer Conjugates, Guilford Jones. Sequential Electron Transfer in Oxidation Reactions Catalyzed by Cytochrome P-450 Enzymes, Peter Guengerich and Timonty L Macdonald. Inner Shell Relaxation Effects on Electron Transfer Reactions of Amino Centered Systems, Stephen F. Nelsen. Index. s s... 

Inorganic reactions exhibit their own trends, examples being outer-sphere electron transfer reactions of transition metal complexes reported by Wherland [70], In this case the rate depends on the difference rr -e because the high frequency solvent response, where n is the refractive index, represents the rapid response of the solvent to changes in the electric field produced by the electron transfer, whereas the permittivity responds much more slowly. Results for the electron exchange constants for ferrocene(0)/(l) studied by McManis et al. [72] and chromium bisdiphenyl(0)/(l) studied by Li and Brubaker [73] are shown in Table 8.7. The rate constants follow approximately the reverse order of the n - e function of the solvents. 

A tris(4-bromophenyl)ammonium hexachloroantimonate catalyst has been utilized to promote a cation radical mechanism in the Diels-Alder cycloaddition polymerization of a bis(diene) with an ionizable bis(dienophile) (Scheme 2). The polymers were obtained with molecular weights up to ca 10 000 and a polydispersity index of ca 2. The electron-transfer reactions of phenols and its derivatives are also important to the polymer industry for the stabilization of polymers, fats and oils. Pulse radiolysis of naphthols and hydroxybiphenyls in n-butyl chloride at room temperature forms two species-phenol-type radical cations and phenoxyl-type radicals. Two different electron-transfer channels are proposed. The naphthol and hydroxybiphenyl radical cations show increased stability compared with phenol radical cations, presumably due to extensive delocalization over the whole aromatic system. 

The electron affinity of the carbocations as measured by red is a useful index for the stability of the carbocations. It is of great interest to correlate the occurrence of three principal reactions between a carbocation and a carbanion, i.e. covalent bond formation (36), single-electron transfer (37) and salt formation (38), with the magnitude of the E ed for the carbocations. 

The degree of polymerization depends on the duration of the process. After 7 min, the molecular mass is equal to 9400 (the polydispersity index is 5.30). When the reaction is carried out for 15 min, the molecular mass of the polymer increases to 37,000 and the polydispersity index reaches 7.31 (Bauld et al. 1996). Depending on whether cation-radical centers arise at the expense of intramolecular electron transfer or in a stepwise intermolecular lengthening, polymerization can occur, respectively, through a chain or a step-growth process (Bauld and Roh 2002). In the reaction depicted in Scheme 7.17, both chain and step-growth propagations are involved. 

MO studies of aromatic nitration cast doubt on the existence of jt-complexes and electron-transfer complexes in liquid-phase nitrations.14 The enthalpy of protonation of aromatic substrates provides a very good index of substrate reactivity to nitration. Coulomb interaction between electrophile and substituent can be a special factor influencing regioselectivity. A detailed DFT study of the reaction of toluene with the nitronium ion has been reported.15 Calculated IR spectra for the Wheland intermediates suggest a classical SE2 mechanism. MO calculations of cationic localization energies for the interaction of monosubstituted benzenes with the nitronium ion correlate with observed product yields.16... 

In electrocatalysis, the presence of surface defects is important to activate electron transfer in complex reactions. This is the consequence of the adsorbed species involved during the electro-catalytic process. Thus, Pt(l 10), the low Miller index plane, deserves special attention in theoretical studies. 

Eisch et al. (24) performed a mechanistic study of the desulfurization of dibenzothiophene by a nickel(0)-bipyridyl complex and reported that a radical anion of the thiophene nucleus was formed and underwent C-S bond cleavage into S and an aromatic radical. In addition, they suggested that the oxidative reaction of the nickel(0)-bipyridyl complex toward dibenzothiophene had the characteristics of stepwise electron transfer rather than nucleophilic attack. However, no correlations occurred between the desulfurization rate and the reaction indexes of Fr(E), Fr(N), and Fr(R), as shown in Table II. The results suggested no evidence for either electron transfer or nucleophilic attack in this study. Moreover, the radical reaction was not... 

CONTENTS Preface. Patrick S. Mariano. Intramolecular Photochemical Electron Transfer (PET) Induced Bond Cleavage Reactions in Some Sulfonium Sal Derivatives. Frar kiin D. Saeva. Aspects of Electron Transfer Promoted Stil-bene Photocycloaddition Reactions. Kevin Peters. Mechanistic and Synthetic Aspects of Amine-Eone SET Photochemistry, Ung Chan Yoon and Richard S. Givens. Index. 

CONTENTS Preface, Patrick. Mariano. Hole and Electron Transfer Catalyzed Pericyclic Reactions. Nathan L. Baufd. Mechanisms and Catalysis In Electron Transfer Chemistry of Redox Coenzyme Analogues, Shunichi Fukuaumi. Electron T ransfer Chemistry of Monoamine Oxidase. Richard B. Silverman. Photol-yase. DNA Repair by Photoinduced Electron Transfer, Aziz San-car. Index. R T7... 

The number of redox couples in the mechanism is entered. Next the integer index is entered for the oxidized and reduced forms of each redox couple, followed by the reduction potential of each couple (in volts), the heterogeneous rate constant (cm/s), and the cathodic transfer coefficient a. For an electron transfer that is considered to be reversible, a value of 10 cm/s will ensure reversibility under most circumstances. If a two-electron transfer (where one of the redox species is shared by two couples) is among the electrode reactions, these should be entered in sequence when written as reductions. For instance ... 

---