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An electron acceptor is a chemical entity that accepts
In
Electron acceptor definition at United States Geological Survey website
{{Authority control Electrochemical concepts
electron
The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...
s transferred to it from another compound. Electron acceptors are oxidizing agent
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ''electron donor''). In ot ...
s.
The electron accepting power of an electron acceptor is measured by its redox potential
Redox potential (also known as oxidation / reduction potential, ''ORP'', ''pe'', ''E_'', or E_) is a measure of the tendency of a chemical species to acquire electrons from or lose electrons to an electrode and thereby be reduced or oxidised respe ...
.
In the simplest case, electron acceptors are reduced by one electron. The process can alter the structure of the acceptor substantially. When the added electron is highly delocalized, the structural consequences of the reduction can be subtle. The central C-C distance in the electron acceptor tetracyanoethylene
Tetracyanoethylene (TCNE) is organic compound with the formula . It is a colorless solid, although samples are often off-white. It is an important member of the cyanocarbons.
Synthesis and reactions
TCNE is prepared by brominating malononitril ...
elongates from 135 to 143 pm upon acceptance of an electron. In the formation of some donor-acceptor complexes, less than one electron is transferred. TTF-TCNQ is a charge transfer complex
In chemistry, charge-transfer (CT) complex, or electron donor-acceptor complex, describes a type of supramolecular assembly of two or more molecules or ions. The assembly consists of two molecules that self-attract through electrostatic forces ...
.
Biology
In biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
, a ''terminal electron acceptor'' often refers to either the last compound to receive an electron in an electron transport chain
An electron transport chain (ETC) is a series of protein complexes and other molecules which transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples th ...
, such as oxygen during cellular respiration
Cellular respiration is the process of oxidizing biological fuels using an inorganic electron acceptor, such as oxygen, to drive production of adenosine triphosphate (ATP), which stores chemical energy in a biologically accessible form. Cell ...
, or the last cofactor to receive an electron within the electron transfer domain of a reaction center during photosynthesis
Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...
. All organisms obtain energy by transferring electrons from an electron donor to an electron acceptor.
One practical illustration of the role of electron acceptors in biology is the high toxicity
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacteria, bacterium, or plant, as well as the effect o ...
of the paraquat
Paraquat ( trivial name; ), or ''N'',''N''′-dimethyl-4,4′-bipyridinium dichloride (systematic name), also known as methyl viologen, is a toxic organic compound with the chemical formula C6H7N)2l2. It is classified as a viologen, a family o ...
. The activity of this broad spectrum herbicide
Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...
results from the electron acceptor property of N,N'-dimethyl-4,4'-bipyridinium.
Materials science
In somesolar cell
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.
s, the photocurrent entails transfer of electrons from a donor to an electron acceptor.
See also
*Acceptor (semiconductors)
In semiconductor physics, an acceptor is a dopant atom that when substituted into a semiconductor lattice forms a p-type region.
When silicon (Si), having four valence electrons, is doped with elements from group III of the periodic table, ...
* Redox reaction
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
* Semiconductor
A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...
References
External links
Electron acceptor definition at United States Geological Survey website
{{Authority control Electrochemical concepts