INDEX radical-anions

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... 

Nitrate is frequently measured using the Griess reagent as an index of NO produced. NO itself participates in both reduction and oxidation reactions. Single electron reduction of NO yields the nitroxyl anion, whereas oxidation reactions yield the nitrosonium cation and N2O3+, via autoxidation. Both the NO radical and nitrosonium cation can be involved in direct reactions with biological systems, specifically with amino acid residues such as cysteine, with the resultant production of nitrosothiols (see later). 

The synthesis of well-defined polymers and of complex polymer architectures has been greatly facilitated by recent developments in controlled radical polymerization, which has opened up new possibilities in the design and also in the preparation of functional nanostructures based on supramolecular assembly. Controlled radical polymerization is an attractive alternative to anionic polymerization for preparing polymeric building blocks of well-defined size and a low polydispersity index... 

The molecular weight of each component in a polymer blend may also be determined. In a model experiment, poly(methyl methacrylate), PMMA, molecular weights were estimated in the presence of polystyrene, PS (90). Anion-ically polymerized polystyrene and free radically polymerized poly(methyl methacrylate) were dissolved in tetrahydrofuran in a 50/50 w/w mix. A dual detector GPC was used, equipped with refractive index (RI) and ultraviolet (UV) detectors. 

Fluorinated poly(methacrylates) or poly(acrylates), rich in trifluoromethyl groups, exhibit superior performance of chemical inertness, excellent weatherability, low refractive index, lower dielectric constant, and special surface properties [14,61]. Poly(2,2,2-trifluoroethyl methacrylate), poly(MATRIF), is an important class of such materials. It has been extensively used in high performance coatings [17], photoelectric communications, and microelectronics [62]. Poly(MATRIF) is easily produced by free radical polymerization using bulk, solution, and emulsion polymerization methods [63]. Structural characterization of NMR of poly(MATRIF) prepared by radical and anionic polymerization has been studied. Syndiotactic structure was obtained by radical initiator in contrast to an isotactic structure achieved by anionic polymerization [64]. 

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