Oxides charge transfer

Dandliker PJ, Nunez ME, Barton JK (1998) Oxidative charge transfer to repair thymine dimers and damage guanine bases in DNA assemblies containing tethered metallointercalators. Biochemistry 37 6491-6502... 

Solid-gas Adsorption Solid aerosol, adsorption, catalysis, corrosion, diffusion, surface energy, thin films, permeation, osmosis, filtration, oxidation, charge transfer, condensation and nucleation... 

In the circuit, Rs is the electrolyte resistance, CPE indicates the double-layer capacitance, Rc, is the methanol oxidation charge-transfer resistance, while R1 and Cl are the mass transfer related resistance and capacitance (mainly due to methanol adsorption or CO coverage). The physical expression of these parameters can be deduced from the reaction kinetics. In the methanol oxidation reaction, the overall charge transfer rate is the sum of each charge-transfer step (rct). The Faradaic resistance (Rj) equals the inverse of the DC polarization curve slope ... 

Proton -Bronsted acid Metal ion -Lewis acid Anion -Host -Electrophile -Hydrogen bond donor -Oxidant -Charge transfer donor -Ion -Radical -Solute -Adsorbent -Enzyme -Carrier (protein) -Receptor -Antibody -... 

The kinetics of the fac lmer isomerization step can be determined quantitatively from the scan-rate dependence of the oxidation process. Both theory and experiment show that the peak potential corresponding to the oxidation of the /ac° species ( p ) shifts to less positive potentials as the scan rate is increased. This occurs because the oxidation charge-transfer process is electrochemically reversible. Under these circumstances, the isomerization step following the charge transfer removes the product and causes the equilibrium position to move to the right in (41), which effectively facilitates the oxidation step. Consequently, at low scan rates, when the isomerization step is important, the oxidation process requires a lower thermodynamic driving force in order to occur and hence a less positive potential is observed. If the electron-transfer (E) step had been irreversible, the isomerization reaction would have no effect on the voltammetric response since the C step would not be rate determining and no kinetic data could be obtained. 

In the presence of nitric oxide, charge transfer to the nitric oxide occurs. 

A novel electron donor-acceptor conjugate, Ce2 /h-Cgo-ZnP has been synthesized and its redox photochemistry has been investigated. It has been demonstrated that this conjugate is capable both of reductive charge transfer (i.e., formation of (Ce2 /h-C8o) -(ZnP) ) in nonpolar media such as toluene/THF), while an oxidative charge transfer i.e., formation of (Ce2 4-Cgo) -(ZnP) ) dominates in polar media i.e., benzonitrile/DMF). ... 

Class 3—Metal to ligand (oxidation) charge-transfer transitions (MLCT)... 

In the ECM (Fig. 12.13), is the ohmic resistance of the solution electrolyte, while Ri and C (constant phase element, CPE), respectively, represent the ionic ohmic resistance and ionic capacitance in the catalyst layer the capacitance (Ci) was replaced by a CPE to more accurately reflect the porous electrode behavior [30]. R2 and C2 represent methanol oxidation charge transfer resistance and interfacial double layer capacitance, respectively, and R represents intermediate adsorbate resistance due to the increase in intermediate adsorbate coverage at the reaction site of the catalyst surface. An adsorbed intermediate, such as CO, can be oxidized to CO2 above a critical potential to result in an inductance, L [28]. The inductance of the instrument in the HF region was not pursued in this ECM. 

Vanadium pentoxide, vanadium(V) oxide, V2O5, is the most important compound in this oxidation state. It is a coloured solid (colour due to charge transfer, p. 60), the colour varying somewhat (red -> brown) with the state of subdivision it is formed when vanadium (or some of its compounds) is completely oxidised, and also by heating ammonium vanadate)V) ... 

Electron donor molecules are oxidized in solution easily. Eor example, for TTE is 0.33V vs SCE in acetonitrile. Similarly, electron acceptors such as TCNQ are reduced easily. TCNQ exhibits a reduction wave at — 0.06V vs SCE in acetonitrile. The redox potentials can be adjusted by derivatizing the donor and acceptor molecules, and this tuning of HOMO and LUMO levels can be used to tailor charge-transfer and conductivity properties of the material. Knowledge of HOMO and LUMO levels can also be used to choose materials for efficient charge injection from metallic electrodes. 

The copper(I) ion, electronic stmcture [Ar]3t/ , is diamagnetic and colorless. Certain compounds such as cuprous oxide [1317-39-1] or cuprous sulfide [22205-45 ] are iatensely colored, however, because of metal-to-ligand charge-transfer bands. Copper(I) is isoelectronic with ziac(II) and has similar stereochemistry. The preferred configuration is tetrahedral. Liaear and trigonal planar stmctures are not uncommon, ia part because the stereochemistry about the metal is determined by steric as well as electronic requirements of the ligands (see Coordination compounds). 

F r d ic Current. The double layer is a leaky capacitor because Faradaic current flows around it. This leaky nature can be represented by a voltage-dependent resistance placed in parallel and called the charge-transfer resistance. Basically, the electrochemical reaction at the electrode surface consists of four thermodynamically defined states, two each on either side of a transition state. These are (11) (/) oxidized species beyond the diffuse double layer and n electrons in the electrode and (2) oxidized species within the outer Helmholtz plane and n electrons in the electrode, on one side of the transition state and (J) reduced species within the outer Helmholtz plane and (4) reduced species beyond the diffuse double layer, on the other. 

Presumably perchloric acid oxidizes the steroids at ring A and these then form charge transfer complexes with picric acid. 

An alternative approach to stabilizing the metallic state involves p-type doping. For example, partial oxidation of neutral dithiadiazolyl radicals with iodine or bromine will remove some electrons from the half-filled level. Consistently, doping of biradical systems with halogens can lead to remarkable increases in conductivity and several iodine charge transfer salts exhibiting metallic behaviour at room temperature have been reported. However, these doped materials become semiconductors or even insulators at low temperatures. 

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