Donor number
Encyclopedia
In chemistry
a donor number or DN is a qualitative measure of Lewis basicity. A donor number is defined as the negative enthalpy
value for the 1:1 adduct formation between a Lewis base and the standard Lewis acid
SbCl5 (antimony pentachloride
), in dilute solution in the noncoordinating solvent 1,2-dichloroethane
with a zero DN. The units are kilocalories per mole
for historical reasons. The donor number is a measure of the ability of a solvent
to solvate
cations and Lewis acids The method was developed by V. Gutmann in 1976. Likewise Lewis acids are characterized by acceptor numbers.
Typical solvent
values are:
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
a donor number or DN is a qualitative measure of Lewis basicity. A donor number is defined as the negative enthalpy
Enthalpy
Enthalpy is a measure of the total energy of a thermodynamic system. It includes the internal energy, which is the energy required to create a system, and the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure.Enthalpy is a...
value for the 1:1 adduct formation between a Lewis base and the standard Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
SbCl5 (antimony pentachloride
Antimony pentachloride
Antimony pentachloride is a the chemical compound with the formula SbCl5. It is a colourless oil, but typical samples are yellowish due to impurities...
), in dilute solution in the noncoordinating solvent 1,2-dichloroethane
1,2-Dichloroethane
The chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene dichloride , is a chlorinated hydrocarbon, mainly used to produce vinyl chloride monomer , the major precursor for PVC production. It is a colourless liquid with a chloroform-like odour...
with a zero DN. The units are kilocalories per mole
Mole (unit)
The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as an amount of a substance that contains as many elementary entities as there are atoms in 12 grams of pure carbon-12 , the isotope of carbon with atomic weight 12. This corresponds to a value...
for historical reasons. The donor number is a measure of the ability of a solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
to solvate
Solvation
Solvation, also sometimes called dissolution, is the process of attraction and association of molecules of a solvent with molecules or ions of a solute...
cations and Lewis acids The method was developed by V. Gutmann in 1976. Likewise Lewis acids are characterized by acceptor numbers.
Typical solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
values are:
- acetonitrileAcetonitrileAcetonitrile is the chemical compound with formula . This colourless liquid is the simplest organic nitrile. It is produced mainly as a byproduct of acrylonitrile manufacture...
14.1 kcal/mol (59.0 kJJouleThe joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
/mol) - acetoneAcetoneAcetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
17 kcal/mol (71 kJ/mol) - methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
19 kcal/mol (79 kJ/mol) - tetrahydrofuranTetrahydrofuranTetrahydrofuran is a colorless, water-miscible organic liquid with low viscosity at standard temperature and pressure. This heterocyclic compound has the chemical formula 4O. As one of the most polar ethers with a wide liquid range, it is a useful solvent. Its main use, however, is as a precursor...
20 kcal/mol (84 kJ/mol) - dimethylformamideDimethylformamideDimethylformamide is an organic compound with the formula 2NCH. Commonly abbreviated as DMF , this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions...
(DMF) 26.6 kcal/mol (111 kJ/mol) - dimethyl sulfoxideDimethyl sulfoxideDimethyl sulfoxide is an organosulfur compound with the formula 2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water...
(DMSO) 29.8 kcal/mol (125 kJ/mol) - ethanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
31.5 kcal/mol (132 kJ/mol) - pyridinePyridinePyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...
33.1 kcal/mol (138 kJ/mol) - triethylamineTriethylamineTriethylamine is the chemical compound with the formula N3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine, for which TEA is also a common abbreviation....
61 kcal/mol (255 kJ/mol)