Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Transfer of electron

Wlien an electrical coimection is made between two metal surfaces, a contact potential difference arises from the transfer of electrons from the metal of lower work function to the second metal until their Femii levels line up. The difference in contact potential between the two metals is just equal to the difference in their respective work fiinctions. In the absence of an applied emf, there is electric field between two parallel metal plates arranged as a capacitor. If a potential is applied, the field can be eliminated and at this point tire potential equals the contact potential difference of tlie two metal plates. If one plate of known work fiinction is used as a reference electrode, the work function of the second plate can be detennined by measuring tliis applied potential between the plates [ ]. One can detemiine the zero-electric-field condition between the two parallel plates by measuring directly the tendency for charge to flow through the external circuit. This is called the static capacitor method [59]. [Pg.1894]

Electrode processes are a class of heterogeneous chemical reaction that involves the transfer of charge across the interface between a solid and an adjacent solution phase, either in equilibrium or under partial or total kinetic control. A simple type of electrode reaction involves electron transfer between an inert metal electrode and an ion or molecule in solution. Oxidation of an electroactive species corresponds to the transfer of electrons from the solution phase to the electrode (anodic), whereas electron transfer in the opposite direction results in the reduction of the species (cathodic). Electron transfer is only possible when the electroactive material is within molecular distances of the electrode surface thus for a simple electrode reaction involving solution species of the fonn... [Pg.1922]

Figure Bl.28.9. Energetic sitiration for an n-type semiconductor (a) before and (b) after contact with an electrolyte solution. The electrochemical potentials of the two systems reach equilibrium by electron exchange at the interface. Transfer of electrons from the semiconductor to the electrolyte leads to a positive space charge layer, W. is the potential drop in the space-charge layer. Figure Bl.28.9. Energetic sitiration for an n-type semiconductor (a) before and (b) after contact with an electrolyte solution. The electrochemical potentials of the two systems reach equilibrium by electron exchange at the interface. Transfer of electrons from the semiconductor to the electrolyte leads to a positive space charge layer, W. is the potential drop in the space-charge layer.
More recent developments are based on the finding, that the d-orbitals of silicon, sulfur, phosphorus and certain transition metals may also stabilize a negative charge on a carbon atom. This is probably caused by a partial transfer of electron density from the carbanion into empty low-energy d-orbitals of the hetero atom ( backbonding ) or by the formation of ylides , in which a positively charged onium centre is adjacent to the carbanion and stabilization occurs by ylene formation. [Pg.6]

We can consider the hydroboration step as though it involved borane (BH3) It sim phfies our mechanistic analysis and is at variance with reality only m matters of detail Borane is electrophilic it has a vacant 2p orbital and can accept a pair of electrons into that orbital The source of this electron pair is the rr bond of an alkene It is believed as shown m Figure 6 10 for the example of the hydroboration of 1 methylcyclopentene that the first step produces an unstable intermediate called a tt complex In this rr com plex boron and the two carbon atoms of the double bond are joined by a three center two electron bond by which we mean that three atoms share two electrons Three center two electron bonds are frequently encountered m boron chemistry The tt complex is formed by a transfer of electron density from the tt orbital of the alkene to the 2p orbital... [Pg.252]

Unlike the reactions that we have already considered, the equilibrium position of a redox reaction is rarely expressed by an equilibrium constant. Since redox reactions involve the transfer of electrons from a reducing agent to an oxidizing agent, it is convenient to consider the thermodynamics of the reaction in terms of the electron. [Pg.146]

When the discharge has been set up, there is a movement of electrons from cathode to anode and a corresponding movement of positive ions from the anode to cathode. These transfers of electrons and ions to each electrode must balance to maintain electrical neutrality in the circuit. Thus, the number of positive ions discharging at the cathode must equal the number of electrons discharging at the anode. This occurs, but the actual drift velocities of electrons and ions toward the respective electrodes are not equal. [Pg.35]

Electron Transport Between Photosystem I and Photosystem II Inhibitors. The interaction between PSI and PSII reaction centers (Fig. 1) depends on the thermodynamically favored transfer of electrons from low redox potential carriers to carriers of higher redox potential. This process serves to communicate reducing equivalents between the two photosystem complexes. Photosynthetic and respiratory membranes of both eukaryotes and prokaryotes contain stmctures that serve to oxidize low potential quinols while reducing high potential metaHoproteins (40). In plant thylakoid membranes, this complex is usually referred to as the cytochrome b /f complex, or plastoquinolplastocyanin oxidoreductase, which oxidizes plastoquinol reduced in PSII and reduces plastocyanin oxidized in PSI (25,41). Some diphenyl ethers, eg, 2,4-dinitrophenyl 2 -iodo-3 -methyl-4 -nitro-6 -isopropylphenyl ether [69311-70-2] (DNP-INT), and the quinone analogues,... [Pg.40]

Chemical, or abiotic, transformations are an important fate of many pesticides. Such transformations are ubiquitous, occurring in either aqueous solution or sorbed to surfaces. Rates can vary dramatically depending on the reaction mechanism, chemical stmcture, and relative concentrations of such catalysts as protons, hydroxyl ions, transition metals, and clay particles. Chemical transformations can be genetically classified as hydrolytic, photolytic, or redox reactions (transfer of electrons). [Pg.218]

Physical Properties. Most of the physical properties discussed herein depend on the direction of measurement as compared to the bedding plane of the coal. Additionally, these properties vary according to the history of the piece of coal. Properties also vary between pieces because of coal s britde nature and the crack and pore stmcture. One example concerns electrical conductivity. Absolute values of coal sample specific conductivity are not easy to determine. A more characteristic value is the energy gap for transfer of electrons between molecules, which is deterrnined by a series of measurements over a range of temperatures and is unaffected by the presence of cracks. The velocity of sound is also dependent on continuity in the coal. [Pg.221]

Mechanism for RMC formation is proposed. Transfer of electrons from ascorbic acid proceeds through Me(III) atoms to molybdenum atoms in mixed POM. Me(III) atoms in heteropolyanion can be oxidized to Me(V) by Mo(VI) making possible easy oxidation of AA. [Pg.156]

Chemical adsorption (known as chemisorptioti) often, but not invariably, involves the formation of a chemical bond (i.e., the transfer of electrons) between the gas and the solid. In other words, a specific chemical compound one layer thick... [Pg.736]

Galvanic corrosion results when two dissimilar metals are in contact, thus forming a path for the transfer of electrons. The contact may be in the form of a direct connection (e.g., a steel union joining two lengths of copper... [Pg.13]

Although the precise mechanism of the NADH-UQ reductase is not known, the first step involves binding of NADH to the enzyme on the matrix side of the inner mitochondrial membrane, and transfer of electrons from NADH to tightly bound FMN ... [Pg.682]

The second step involves the transfer of electrons from the reduced [FMNHg] to a series of Fe-S proteins, including both 2Fe-2S and 4Fe-4S clusters (see Figures 20.8 and 20.16). The unique redox properties of the flavin group of FMN are probably important here. NADH is a two-electron donor, whereas the Fe-S proteins are one-electron transfer agents. The flavin of FMN has three redox states—the oxidized, semiquinone, and reduced states. It can act as either a one-electron or a two-electron transfer agent and may serve as a critical link between NADH and the Fe-S proteins. [Pg.682]

A particularly elegant route to metallacarbor-anes is the direct oxidative insertion of a metal centre into a c/oso-carborane cluster the reaction uses zero-valent derivatives of Ni, Pd and Pt in a concerted process which involves a nett transfer of electrons from the nucleophilic metal centre to the cage ... [Pg.191]

These data, and the other properties of C M, suggest that bonding occurs by transfer of electrons from the alkali metal atoms to the conduction band of the host graphite. Consistent with... [Pg.293]


See other pages where Transfer of electron is mentioned: [Pg.152]    [Pg.240]    [Pg.124]    [Pg.1923]    [Pg.3018]    [Pg.332]    [Pg.173]    [Pg.3]    [Pg.237]    [Pg.163]    [Pg.287]    [Pg.287]    [Pg.440]    [Pg.464]    [Pg.420]    [Pg.289]    [Pg.24]    [Pg.236]    [Pg.245]    [Pg.252]    [Pg.239]    [Pg.55]    [Pg.212]    [Pg.753]    [Pg.24]    [Pg.17]    [Pg.162]    [Pg.92]    [Pg.3]    [Pg.718]    [Pg.722]    [Pg.63]    [Pg.295]   
See also in sourсe #XX -- [ Pg.90 , Pg.149 , Pg.448 ]

See also in sourсe #XX -- [ Pg.90 , Pg.149 , Pg.448 ]




SEARCH



A Transition-State Perspective of Proton-Coupled Electron Transfers

A molecular theory of the nonadiabatic electron transfer rate

Acid catalysis, of photoinduced electron transfer

Adiabaticity of electron transfer

Amplitude of Electron Tunneling Transfer

Applicability of Time-Dependent Perturbation Theory for Electron Transfer Processes at Electrodes

Application of Marcus Theory to other Protein Electron Transfer Reactions

Applications of Enzymes Electrically Contacted by Mediated Electron-transfer

Attachment of electron-transfer relays

Behavior of Isotope Mixtures in Electron-Transfer Reactions

Biosensors based on direct electron transfer of GOD

Biosensors based on direct electron transfer of catalase

Biosensors based on direct electron transfer of enzymes

Biosensors based on direct electron transfer of hemoglobin

Biosensors based on direct electron transfer of horseradish peroxidase

Biosensors based on direct electron transfer of myoglobin

Biosensors based on direct electron transfer of other active enzymes

Biosensors based on direct electron transfer of proteins

Biosensors based on direct electron transfer of proteins cytochrome

Carbon nanotubes -based electrochemical direct electron transfer, of proteins and

Chemistry of Extracellular Electron Transfer

Collisional Transfer of Electronic Energy

Continuum dielectric theory of electron transfer processes

Coupling of Single Electron Transfer with Acid-Base Reactions

Current understanding of ultrafast electron transfer

Cyclic Voltammetry of Fast Electron Transfers Nernstian Waves

Details of electron transfer

Direct Transfer of Electrons

Direct electron transfer of GOD

Direct electron transfer of HRP

Direct electron transfer of catalase

Direct electron transfer of cytochrome

Direct electron transfer of enzymes

Direct electron transfer of hemoglobin

Direct electron transfer of myoglobin

Direct electron transfer of other active enzymes

Direct electron transfer of protein

Direct electron transfer of protein advantage

Direct electron transfer of protein biosensors based

Direct electron transfer of protein catalase

Direct electron transfer of protein cytochrome

Direct electron transfer of protein glucose oxidase

Direct electron transfer of protein hemoglobin

Direct electron transfer of protein horseradish peroxidase

Direct electron transfer of protein horseradish peroxide

Direct electron transfer of protein myoglobin

Direct electron transfer of protein uricase

Direct electron transfer of protein xanthine oxidase

Direct electron transfer of proteins and enzymes on carbon nanotube

Direction of electron transfer

Distance Dependence of Electron Transfer

Distance dependence of electron transfer rates

Dynamics of electron transfer

Electric Double-Layer Effects on the Elementary Act of Electron Transfer

Electrodes kinetics, of electron-transfer

Electron Affinities of Charge Transfer Complex Acceptors

Electron Spin Polarization Transfer from Radicals of Photoinitiators to Stable Nitroxyl Polyradicals

Electron Transfer Induced Rearrangements of Cyclopropanes and Consecutive Reactions

Electron Transfer Partners of Cytochrome

Electron Transfer Pathway Coupled to the Oxidation of Ammonia

Electron Transfer Reaction of the Excited State

Electron Transfer Reactions of Myoglobin

Electron Transfer System Coupled to Oxidation of Ferrous Ion

Electron Transfer at the Interface of Two Immiscible Liquids

Electron Transfer in Mixed Phase of Anatase and Rutile

Electron Transfer in Self-organizing Systems of Amphiphiles

Electron Transfer in the Mediatorless Method of Bioelectrocatalysis

Electron and Energy Transfer Dynamics of Adsorbed Monolayers

Electron transfer from redox sites of proteins to excited simple molecules

Electron transfer of SOD

Electron transfer of carbanions

Electron transfer of exoelectrogens

Electron transfer reactions of fullerenes

Electron transfer reactions photochemical decomposition of water

Electron-Transfer Reactions with Participation of Ion-Radical Aggregates

Electron-Transfer Reduction of

Electron-transfer Pathway of

Electron-transfer Reactions of Amines

Electron-transfer Reactions of Aromatic Compounds

Electron-transfer Reactions of Bicyclic Systems

Electron-transfer Reactions of Carbonyl Compounds

Electron-transfer Reactions of Cycloalkanes

Electron-transfer Reactions of Heteroaromatic Compounds

Electron-transfer in outer-sphere reactions of metal ions

Electron-transfer reactions of polynuclear

Electronic Structures of EMFs Intramolecular Charge Transfer

Energetics of electron transfer between two ionic centers

Energy of activation for electron transfer

Environmental Effects on Rates of Electron Transfer

Equilibrium potential of electron transfer reactions

Examples of Electron Transfer Rate Measurement using ER Signal

Examples of Electron Transfer Reactions

Experimental Test of Bridge-assisted Electron Transfer Models

Experimental Testing of the Electron Transfer Models

Expression of the Electron Transfer Rate

Expression of the Electron Transfer Rate for a Non-adiabatic Process

Extended Acceptor Systems Observation of Photoinduced Electron Transfer

Extraction of Electron Transfer Kinetics from Cyclic Voltammetric Signals. Comparison with Other Techniques

Features of Electron Transfer

Fractional number of electrons transferred

Free energy of electron transfer

Free energy of photoinduced electron transfer

Fundamental Studies of Electron Transfer in Organized Assemblies

Fundamentals of Electron Transfers at an Electrode

General Consideration of the Electron Transfer Process in Solution

Gibbs free energy, of electron transfer

Inhibition of Electron Transfer at Partially Blocked Electrodes

Ions Transfer of Electrons

KINETICS OF HOMOGENEOUS REACTIONS COUPLED TO HETEROGENEOUS ELECTRON TRANSFER

Kinetic Complexity of Protein Electron Transfer Reactions

Kinetics and Mechanisms of Biological Electron Transfer Reactions

Kinetics of Electron Transfer at Electrodes

Kinetics of Electron Transfer at the Metal-Liquid Interface

Kinetics of Electron Transfer between Dye and Semiconductor Electrode

Kinetics of Electron Transfer in RC Protein from Rhodobacter sphaeroides

Kinetics of Electron Transfer in the Reaction Centre Proteins from Photosynthetic Bacteria

Kinetics of electron transfer

Kinetics of electron transfer and

Kinetics of electron-transfer catalysis

Kinetics of electron-transfer reactions

Kinetics of heterogeneous electron transfer

Kinetics of intramolecular electron transfer

Light-Induced Electron-Spin Resonance Detection of the Charge Transfer Process

Marcus model of electron transfer

Marcus theory of electron transfer

Marcus theory of outer-sphere electron transfer

Measurement of electron transfer

Mechanism of electron transfer

Mechanism of successive electron transfers

Mechanisms of Electron Transfer Across Membranes

Mechanisms of Electron Transfer in DNA

Mechanisms of Energy and Electron Transfer

Microscopic interpretation of electron transfer

Models of Bond-Breaking Ion and Electron Transfer Reactions

Models of electrochemical electron transfer kinetics

Modifications of the Substrate before Electron Transfer

Modulation of Electron Transfer Dynamics by Electric Fields

Number of transferred electrons

Optimisation of photoinduced electron transfer in photoconversion

Oxidation of Metallocenes and Electron Transfer Reactions

Photocurrent and the Gibbs Free Energy of Electron Transfer

Photoinduced Electron Transfer Reactions of Gold Complexes

Photoinduced Electron-Transfer Processes of Phthalimides

Plane of electron transfer

Polarization curves of redox electron transfers

Probability of electron transfer

Production of Excited Molecules by Electron Transfer

Quantum Mechanics of Electron Transfer

Quantum mechanical treatments of electron transfer processes

Quantum theory of electron-transfer reactions

Radiationless transfer of electronic

Radiationless transfer of electronic excitation

Rate of Electron Transfer (Theory)

Rates of Electron Transfer Reactions

Rates of Heterogeneous Electron Transfer Reactions

Rates of electron transfer

Reactions Controlled by the Rate of Electron Transfer

Recognition Based on Cation Control of Photoinduced Electron Transfer in Nonconjugated Donor-Acceptor Systems

Redox potentials of electron transfer

Reduction of Carbon-Centered Radicals by Electron Transfer

Regularities of Photoinduced Tunnel Electron Transfer Processes

Reorganization Energies of Optical Electron Transfer Processes

Reorganization Energies of Optical Electron Transfer Processes R. D. Cannon

Single Turnover Stopped-Flow Studies of Electron Transfer

Single electron transfer reaction of perfluoroalkyl halides

Site-Directed Mutagenesis in the Study of Substrate Selectivity and Electron Transfer

Specific Aspects of Photoinduced Electron Transfer in Organic -Conjugated Systems

Spectroelectrochemistry in the Monitoring of Chemical Reactions Following Electron Transfer

Speed of electron transfer

Steps in the Transfer of Valence Electrons

Studies Focusing on Electron Transfer Kinetics of Organic Systems

Studies of Heterogeneous Electron Transfer

Studies of Ultrafast Electron Transfer in a Light-Activated Protein

Study of Energy-Transfer Processes in Electronic Ground States

The Asymmetry of Primary Electron Transfer

The Dynamics of Electron Transfer (Kinetics and Thermodynamics)

The Importance of Energy Changes and Electron Transfer in Metabolism

The Ionic Bond Transfer of Electrons from One Atom to Another

The Marcus Theory of Electron Transfer

The Marcus-Hush Model of Electron Transfer

The Mechanism of Electron Transfer

The Theory of Electron Transfer

The Theory of Homogeneous Electron Transfer

The distance dependence of electron transfer rates

The interplay of electron transfer and mass transport control

The mechanism of electron transfer at an electrode

The rates of electron transfer processes

Theoretical Aspects of Electron Transfer

Theories of Photoinduced Electron Transfer

Theory of Electron Transfer

Theory of Electron Transfer Reactions

Theory of Heterogeneous Electron-Transfer Reactions

Theory of Outer-Sphere Electron Transfer

Theory of Outer-Sphere Electron Transfer Reactions

Theory of Proton and Electron Transfer in Liquids

Theory of the Electron Transfer Process

Thermodynamic Aspects of Excited State Electron Transfer Reactions

Thermodynamics of Electron-transfer Quenching

Thermodynamics of electron transfer

Thermodynamics of electron transfer reactions

Transfer of electronic energy

Transference numbers of electrons

Tunneling in Electron Transfer Reactions of Excited Molecules

Types of Electron Transfer Reactions

© 2024 chempedia.info