Radical anions reactions with

In the case of bisulfite, the primary propagation reaction involved the perox-ymonosulfate radical anion reaction with HSCV as follows ... 

Lithiating agent S.5.2.3.5 Li naphthalide radical anion Reaction with RX 5.5.2.2.1 C, H,LiN2... 

Figure 4, Correlations of anion, radical, and radical anion reactions with organic halides and the halide effect...

Abstract Inorganic polysulfide anions and the related radical anions S play an important role in the redox reactions of elemental sulfur and therefore also in the geobio chemical sulfur cycle. This chapter describes the preparation of the solid polysulfides with up to eight sulfur atoms and univalent cations, as well as their solid state structures, vibrational spectra and their behavior in aqueous and non-aqueous solutions. In addition, the highly colored and reactive radical anions S with n = 2, 3, and 6 are discussed, some of which exist in equilibrium with the corresponding diamagnetic dianions. 

Under physiological conditions, the disproportionation of superoxide radical is very fast and involves reaction of the radical anion 02 with a molecule of the neutral radical, H02 (Eq. 2, Scheme 8.36). Disproportionation yields one molecule of molecular oxygen and one molecule of hydrogen peroxide. 

Dopamine (10) has also been the subject of some study. Maity and coworkers17 have studied the pulse radiolysis or /-irradiation induced reduction of the protonated form. In this instance the addition of an electron affords the radical anion 11 with a bimolecular rate constant for the reaction of 2.5 x 108 M-1 s-1. 

Concerning the reactivity of the dianion 2 compared to that of the radical-anion 1, the first one behaves as a typical lithiating agent toward alkyl chlorides displaying an outer-sphere electron transfer reactivity profile no significant kinetic differences are found in the reaction of dianion 2 (as well as the radical-anion 1) with primary, secondary, tertiary and phenyl chlorides. On the other hand, a notable difference has been found in the reactivity of both species with several substrates and solvents . 

In Sch. 1, if the 002 radical anion reacts with CO2 in solution, CO is formed via a dimeric intermediate in which a C—O bond is formed. A second electron transfer to this intermediate from either the electrode or 002 leads to the formation of carhon monoxide. The ultimate result of this pathway is the formation of the two-electron reduction product, carbon monoxide, and carbonate. In this reaction, a second CO2 molecule acts as the acceptor of the oxide ion formed in the two-electron reduction of CO2 to CO. Many of the features of these reactions are common to the catalyzed reactions discussed in the following. Because free C02 is not present in the catalyzed two-electron reductions of CO2 to CO, the reduction potentials can be considerably less negative than that required to form CO2-. 

It is useful to briefly discuss some of the common and, perhaps, less common experimental approaches to determine the kinetics and thermodynamics of radical anion reactions. While electrochemical methods tend to be most often employed, other complementary techniques are increasingly valuable. In particular, laser flash photolysis and photoacoustic calorimetry provide independent measures of kinetics and thermodynamics of molecules and ion radicals. As most readers will not be familiar with all of these techniques, they will be briefly reviewed. In addition, the use of convolution voltammetry for the determination of electrode kinetics is discussed in more detail as this technique is not routinely used even by most electrochemists. Throughout this chapter we will reference all electrode potentials to the saturated calomel electrode and energies are reported in kcal mol. ... 

The radical anion of /3-trimethylsilylstyrene also undergoes dimerization but coupling takes place at the carbons a to silicon 33). The kinetics of the alkyne dimerization, followed by ESR, showed the reaction to be second order in radical anion 43). With Li+, Na+, K+, or Rb+ as the counterions, the rate increases in the order Si < C < Ge 45). Consistent with the increased stability of the trimethylsilyl-substituted radical anion, the radical anion of 1,4-bis(trimethylsilyl)butadiyne, produced by reduction with Li, Na, K, Rb, or Cs in THF is stable at room temperature even on exposure to air, whereas the carbon analog, 1,4-di-r-butyl-1,3-butadiyne radical anion, dimerizes by second-order kinetics at -40° (42). The enhanced stability of the trimethylsilylalkynyl radical anions has been attributed to p-drr interactions (42). 

The eel arises from the reaction of the radical anion C02 with [Ru(bipy)3]3+. It was noted that some quenching of [Ru(bipy)3] 2+ by the ruthenium(III) complex was possible. 

Although the redox potential of-OH is very high [E( OI I/OE I ) = +1.9 V (Klan-inget al. 1985) E(-OH, H+/H20) = 2.73 (Wardman 1989)], direct ET is rarely observed in OH-reactions, and where it occurs intermediate complexes are likely to be involved. For example, in its reaction with thiocyanate, where the final product is the three-electron bonded dirhodane radical anion [reaction (31) for other three-electron bonded systems, see Chaps. 5 and 7], a similar three-electron bonded intermediate might precede ET [reactions (29) and (30)]. 

Hydroxyl radicals react with many halide (pseudohalide) ions at close to diffusion-controlled rates thereby forming a three-electron-bonded adduct radical [e.g., reaction (1) k = 1.1 x 1010 dm3 mol-1 s 1 Zehavi and Rabani 1972], These adducts may decompose into OH" and the halide (pseudohalide) radical which then complexes with another halide (pseudohalide) ion yielding the dihalogen radical anion [reactions (2) and (3) k2 = 4.2 x 106 s"1 k3 1010 dm3 mol"1 s"1 for resonance Raman spectra of such intermediates, see Tripathi et al. 1985]. 

Thy and Ura behave like typical carbonyl compounds, and the first intermediate is a radical anion [reaction (163), in the case of Thy/Thd] which is in equilibrium with its O-protonated conjugate acid [equlibrium (164)]. 

Chatgilialoglu C, loele M, Mulazzani QG (2005) Reactions of oxide radical anion (O -) with pyrimidine nucleosides. Radiat Phys Chem 72 251-256... 

In most experiments and applications with titanium dioxide photocatalysts, molecular oxygen is present to act as the primary electron acceptor. Usually the electrons trapped as Ti(III) are transferred to dioxygen adsorbed at the semiconductor surface yielding peroxyl radical anions (reaction (7.16)) [16]. 

Mattay et al. used triethylamine as electron donor in tandem fragmentation/cyclization reactions of a-cyclopropylketones (49) [48]. The initial electron transfer to the ketone moiety is followed by subsequent cyclopropylcarbinyl-homoallyl rearrangement yielding a distonic radical anion (50). With an appropriate unsaturated side chain attached to the molecule both annelated and spirocyclic ring systems are accessible in moderate yields. Scheme 26 shows some representative examples. 

---