Benzonitrile electron transfer rate

The first-order rate constant can be evaluated from the decay curves of 3C o and the rise curves of Qo and the donor radical cation [125,154], The observed electron transfer rate constants for C6o are usually in the order of 109-1010 dm3 mol-1 s-1 and thus near the diffusion controlled limit which depends on the solvent (e.g., diffusion controlled limit in benzonitrile -5.6 X 109 M-1 s-1) [120,125,127,141,154-156],... 

Table 6 Electrontransfer Rate Constants and Back-Electron Transfer Rate Constants of 3C60 and 3C60-Pyrrolidino Derivatives With DMA in Benzonitrile and Benzonitrile/ Toluene (1 1)...

Laser flash photolysis experiments showed that the (Reaction 8.17) reacts with cyclic oligosilanes 42, 43 and 44 in benzonitrile by an electron transfer mechanism [43]. The rate constant ( et) for the three-membered cyclic compound 42 is found to be 7.0 x 10 M s, whereas for the other two compounds it was more than two orders of magnitute lower, i.e., (1-2) X 10 M- s-. ... 

Hydrogen atoms and hydroxyl radicals react with aliphatic compounds mainly by H-abstraction from the chain, although reactions with certain substituents are also important. With hydrated electrons the functioned group is the only site of reaction and its nature determines the reactivity. The reactions of hydrated electrons are by definition electron transfer reactions. The rate of reaction of a certain substrate will depend on its ability to accommodate an additional electron. For example, in an unsaturated compound the rate may depend on the presence of a site with a partial positive charge. Thus acrylonitrile and benzonitrile are three orders of magnitude more reactive toward e q than are ethylene and benzene. On the other hand, this large difference does not exist in the case of addition of H and OH. 

Irradiation of a solution containing MA (2 x 10 M) and Ceo in benzonitrile produced weak transient absorption at 980 nm, [77] assigned to the C o radical cation because of its similarity to the spectrum reported by Kato et al. [65,66]. The spectrum is nearly identical to that of the radical cation reported recently from a pulse-radiolysis experiment [78] and in an argon matrix [79]. From the risetime of the signal and the Ceo concentration, the rate constant for electron transfer is diffusion-controlled. 

The efficiency of electron-transfer reduction of Cgo can be expressed by the selfexchange rates between Coo and the radical anion (Ceo ), which is the most fundamental property of electron-transfer reactions in solution. In fact, an electrochemical study on Ceo has indicated that the electron transfer of Ceo is fast, as one would expect for a large spherical reactant. This conclusion is based on the electroreduction kinetics of Ceo in a benzonitrile solution of tetrabutylammonium perchlorate at ultramicroelectrodes by applying the ac admittance technique [29]. The reported standard rate constant for the electroreduction of Ceo (0.3 cm s ) is comparable with that known for the ferricenium ion (0.2 cm s l) [22], whereas the self-exchange rate constant of ferrocene in acetonitrile is reported as 5.3 x 10 s , far smaller than the diffusion limit [30, 31]. 

Table 3. Free energy change, AG°ct, and rate constants, of photoinduced electron transfer from group 14 organometallic electron donors to C, observed rate constants, obs, triplet quenching rate constants, kq, and limiting quantum yields, Oco, in the photoaddition of the donors to in benzonitrile at 298 K [212].

Would the tricarbonyl manganese function in monomer 8 prevent homopolymerization, or undergo electron transfer from manganese to the propagating radical center Homopolymerization kinetic studies in benzene, benzonitrile, and acetone demonstrated that the effect of manganese was different than that of iron in 1. The rate law was three halves order in the concentration of monomer 8 and half-order in initiator concentration.53... 

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