Water intermolecular electron transfer reactions

INTERMOLECULAR ELECTRON TRANSFER REACTIONS IN THE PHOTOCHEMICAL DECOMPOSITION OF WATER... 

Intermolecular electron transfer reactions of S-heterocycles 02ACR247. Removing dithiolane- and oxathiolane-protecting groups using CeCl3 H20/Nal as an efficient water-tolerant Lewis acid 03SL2101. 

Two findings are particularly noteworthy. First, the experiments in which the reactivity of water-soluble fullerene derivatives in aqueous media was probed (62-64) Not only, that the intermolecular reactions with hydrated electron and various radicals provided unequivocally evidence for the presence of fullerene clusters. But, furthermore, these investigations helped, in reference to the kinetics of the fullerene monomers, to estimate the agglomeration number for, for example, the mono pyrrolidinium salt in the respective fullerene cluster. Secondly, the intermolecular electron transfer reactions between radiolytically generated arene tt-radical cations and higher fullerenes (25,51) The noted parabolic dependence of the rate constants on the thermodynamic driving force is one of the rare confirmations of the existence of the Marcus-Inverted region in forward electron transfer. 

For the cyano-Ru(II) complexes in neat water, the heats derived from the intercepts of plots with Equation [11] afforded values of the energy content of the MLCT states similar to those derived from emission data. Both for intra- and intermolecular electron transfer reactions of cyano-Ru(II) complexes in aqueous solutions in the presence of salts, the structural volume change correlates with the entropy change of the reaction. An enthalpy-entropy compensation effect occurs upon perturbation of the water structure by the addition of the salts. 

Solutions of indium (I) can be prepared by treatment of indium amalgam with silver triflate in dry acetonitrile in the absence of oxygen, and then diluted with water to give the low-concentration aqueous solution, which plays a sizable role in the study of the details of intermolecular electron transfer processes in solution. Aqueous In(I) solution has been used to examine the behavior of this hypovalent center in inorganic redox transformations. Reactions with complexes of the type [(NH3)5Co (Lig)] and [(NH3)5Ru (Lig)] (Tig = Cl, Br , I or HC2O4 ) show two consecutive one-electron reactions initiated by the formation of the metastable state In , which is then rapidly oxidized to In , and the first of which is predominating an inner-sphere mechanism. ... 

The mechanism of this reaction involves an equilibrium between the 1- and 2-adamantyl cations established via intermolecular hydride transfers. Direct 1,2-hydride shifts on the adamantyl nucleus are inhibited by the unfavorable stereo-electronic relationship between the vacant orbital and the migrating group as discussed previously (see Fig. 1) 5 ). The 2-adamantyl cation, once formed, is trapped by water. The resulting 2-hydroxadamantane apparently then undergoes a disproportionation reaction with an adamantyl cation to give adamantanone and adamantane. The overall reaction is summarized in Scheme 15. 

The exact nature of the reaction (oxidative vs. reductive) will depend on the redox properties of I ) and Q. The electron transfer process is a special case of exciplex formation favored in the strongly polar solvents, such as water. The involvement of an exciplex in a photochemical reaction is generally established by studying the effects of known exciplex quenchers such as amines on the exciplex fluorescence and the product formation. The heavy atom effect, due to the presence of substituents such as bromine or iodine intra- or intermolecularly, causes an exciplex to move to the triplet state preferentially, with a quenching of fluorescence. 

Many phenomena of interest in science and technology take place at the interface between a liquid and a second phase. Corrosion, the operation of solar cells, and the water splitting reaction are examples of chemical processes that take place at the liquid/solid interface. Electron transfer, ion transfer, and proton transfer reactions at the interface between two immiscible liquids are important for understanding processes such as ion extraction, " phase transfer catalysis, drug delivery, and ion channel dynamics in membrane biophysics. The study of reactions at the water liquid/vapor interface is of crucial importance in atmospheric chemistry. Understanding the behavior of solute molecules adsorbed at these interfaces and their reactivity is also of fundamental theoretical interest. The surface region is an inhomogeneous environment where the asymmetry in the intermolecular forces may produce unique behavior. 

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