Hydrated electron reducing agent

In the original study by Padam and Gupta [112], the deposition solution contained triethanolamine/ammonia-complexed CdAci and the Te source was TeOi with hydrazine hydrate as a reducing agent. The nature of the TeOi solution was not clear, since TeOi is only slightly soluble in water it may have been dissolved in a hydroxide solution, in which it is much more soluble. The deposition was carried out at 90°C. Electron diffraction of the as-deposited films showed both zincblende and wurtzite phases of CdTe (the zincblende phase is the more stable and commonly encountered one). 

Thus a mixture of strong single electron oxidizing- and reducing-agents is formed. However the hydrated electrons can be transformed into hydroxyl radicals via (7) ... 

The table shows that the very high energy of hydration of the lithium ions (due to their tiny size) makes lithium the best reducing agent even though cesium is the best electron donator. 

This narrative echoes the themes addressed in our recent review on the properties of uncommon solvent anions. We do not pretend to be comprehensive or inclusive, as the literature on electron solvation is vast and rapidly expanding. This increase is cnrrently driven by ultrafast laser spectroscopy studies of electron injection and relaxation dynamics (see Chap. 2), and by gas phase studies of anion clusters by photoelectron and IR spectroscopy. Despite the great importance of the solvated/ hydrated electron for radiation chemistry (as this species is a common reducing agent in radiolysis of liquids and solids), pulse radiolysis studies of solvated electrons are becoming less frequent perhaps due to the insufficient time resolution of the method (picoseconds) as compared to state-of-the-art laser studies (time resolution to 5 fs ). The welcome exceptions are the recent spectroscopic and kinetic studies of hydrated electrons in supercriticaF and supercooled water. As the theoretical models for high-temperature hydrated electrons and the reaction mechanisms for these species are still rmder debate, we will exclude such extreme conditions from this review. 

The metallotexaphyrins have also been found to be easy to reduce and capable of capturing hydrated electrons in aqueous solution. This has made them of potential interest as X-ray radiation therapy (XRT) enhancement agents. While a discussion of this and other applications of metallotexaphyrins is deferred to Chapter 10 of this book, it is worth mentioning that preliminary results have been obtained that are highly encouraging. This, in turn, is stimulating on-going efforts to prepare additional texaphyrin and texaphyrin-like macrocycles. ... 

The physical properties of significance here are summarized in Table 2. The hydrated electron and the hydrogen atom are strong reducing agents and the hydroxyl radical is a powerful oxidant. Because of these properties, they are very effective in bringing about one-electron changes in molecules and ions. 

The hydrated electron is a powerful reducing agent and will reduce water and the hydrogen ion according to ... 

The electron in H O becomes fully hydrated in ps time to become a discrete chemical species with a known charge (—1), ionic conductivity (190 cm 0 and diffusion coefficient (4.9 X 10 cm s )- From estimates of its thermodynamic quantities, the standard redox potential of [e ] is ca. —2.87 V, making it a powerful reducing agent. Because of its intense and broad optical absorption spectrum, (A = 710 nm ma. = cm ) extending from the UV into the ir and its relatively long... 

After the discovery of hydrated electrons extensive experimental data in radiation chemistry have been accumulated, which show that the solvated electron acts as a universal primary reducing agent in the processes that take place in the liquid bulk under the action of ionizing radiation. This provoked interest among researchers in the role of solvated electrons in other physico-chemical processes also, in particular in electrochemical processes. 

Reduction of triarylbismuth dihalides to the parent triarylbismuthines can be performed by using a variety of reducing agents, which include hydrazine hydrate, sodium hydrosulfite, liquid ammonia, LiAlH4, NaBH4, sodium sulfide and sodium dialkyldithiocarbamate. This type of reduction has been used for the purification of tris(3-methylphenyl)bismuthine which is purified with difficulty in the trivalent state [26JA507]. The electrolytic reduction of triphenyl-bismuth dibromide has been found to be a one-step, two-electron process where the bromine atoms are released as bromide ions [66JA467]. 

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