Secondary electron transfer

Several MALDl ionization-relevant papers have appeared in a special issue of the European Journal of Mass Spectrometry (volume 12,2006) Proton transfer reactions in the plume were the object of experimental work by the Kinsel group and calculations by Beran and co-workers. Hoteling et al. considered electron transfer secondary reactions, which are also of relevance for the fullerenes studied with solvent-firee methods by Drewello s group. Finally, cluster ionization and desolavtion processes were investigated by Tabet and CO-workers " Also appearing in 2006 was a mechanisms review by Knochenmuss in The Analyst ... 

The pathway model makes a number of key predictions, including (a) a substantial role for hydrogen bond mediation of tunnelling, (b) a difference in mediation characteristics as a function of secondary and tertiary stmcture, (c) an intrinsically nonexponential decay of rate witlr distance, and (d) patlrway specific Trot and cold spots for electron transfer. These predictions have been tested extensively. The most systematic and critical tests are provided witlr mtlrenium-modified proteins, where a syntlretic ET active group cair be attached to the protein aird tire rate of ET via a specific medium stmcture cair be probed (figure C3.2.5). 

Beratan D N, Betts J N and Onuchic J N 1991 Protein electron transfer rates set by the bridging secondary and tertiary structure Science 252 1285-8... 

The PSII complex contains two distinct plastoquiaones that act ia series. The first is the mentioned above the second, Qg, is reversibly associated with a 30—34 kDa polypeptide ia the PSII cote. This secondary quiaone acceptor polypeptide is the most rapidly tumed-over proteia ia thylakoid membranes (41,46). It serves as a two-electron gate and connects the single-electron transfer events of the reaction center with the pool of free... 

Nitro groups attached to a primary and secondary alkyl group in a highly basic (pH > 13) medium exist as the nitronate (enolate) anions. These anions must be very difficult to reduce by electron transfer and are surely much more difficult to reduce than water. Since the electrohydrogenation of such nitro compounds to the corresponding amines is veiy efficient at Raney metal cathodes in 0.1 to 0.15 M KOH (or NaOH) aqueous alcohol (pH > 13) (12), as... 

J.R. Bolton If the electron reaches the quinone via the linkage, then the transfer must involve the molecular orbitals of the linking structure and thus the solvent will have only a secondary effect. If the electron transfer occurs through the solvent, then the solvent should have a first-order effect on the rate. 

The second part of the database contains reactions for the various secondary species, minerals, and gases. These reactions are balanced in terms of the basis and redox species, avoiding (to the extent practical) electron transfer. Species and minerals containing ferric iron, for example, are balanced in terms of the redox species Fe+++,... 

This scheme implies that dioxygen is activated only in a secondary step by an intermediate formed in the initial electron transfer reaction between the metal ion and a co-substrate, Si- The reduced form of the metal ion is re-oxidized to its original oxidation state by O2, but such a reaction with a secondary intermediate cannot be excluded. If the rate determining step is Eq. (9), the overall reaction is again zeroth order with respect to dioxygen. 

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