Selectfluor, a trademark of

Air Products and Chemicals Air Products and Chemicals, Inc. is a U.S.-based international corporation whose principal business is selling gases and chemicals for industrial use. Air Products is headquartered in Trexlertown, Pennsylvania, in the Lehigh Valley region of east ...

, is a

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

that is used as a

fluorine Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...

donor. This compound is a derivative of the nucleophillic base

DABCO DABCO (1,4-diazabicyclo .2.2ctane), also known as triethylenediamine or TEDA, is a bicyclic organic compound with the formula N2(C2H4)3. This colorless solid is a highly nucleophilic tertiary amine base, which is used as a catalyst and reagent in ...

. It is a colourless salt that tolerates air and even water. It has been commercialized for use for

electrophilic fluorination Electrophilic fluorination is the combination of a carbon-centered nucleophile with an electrophilic source of fluorine to afford organofluorine compounds. Although elemental fluorine and reagents incorporating an oxygen-fluorine bond can be used fo ...

Preparation

: Selectfluor is synthesized by the ''N''-

alkylation Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting al ...

of diazabicyclo .2.2ctane (DABCO) with

dichloromethane Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with ...

in a

Menshutkin reaction In organic chemistry, the Menshutkin reaction converts a tertiary amine into a quaternary ammonium salt by reaction with an alkyl halide. Similar reactions occur when tertiary phosphines are treated with alkyl halides. The reaction is the m ...

, followed by

ion exchange Ion exchange is a reversible interchange of one species of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid. Ion exchange is used in softening or demineralizing of water, purification of ch ...

with sodium tetrafluoroborate (replacing the chloride

counterion 160px, cation-exchange_resin.html" ;"title="Polystyrene sulfonate, a cation-exchange resin">Polystyrene sulfonate, a cation-exchange resin, is typically supplied with as the counterion. In chemistry, a counterion (sometimes written as "counter ...

for the tetrafluoroborate). The resulting salt is treated with elemental fluorine and sodium tetrafluoroborate: The cation is often depicted with one skewed ethylene ((CH₂)₂) group. In fact, these pairs of CH₂ groups are eclipsed so that the cation has idealized C_3h

symmetry Symmetry () in everyday life refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is Invariant (mathematics), invariant und ...

Mechanism of fluorination

Electrophilic fluorinating reagents could in principle operate by electron transfer pathways or an S_N2 attack at fluorine. This distinction has not been decided. By using a charge-spin separated probe, it was possible to show that the electrophilic fluorination of stilbenes with Selectfluor proceeds through an SET/fluorine atom transfer mechanism. In certain cases Selectfluor can transfer fluorine to alkyl radicals.

Applications

The conventional source of "electrophilic fluorine", i.e. the equivalent to the

superelectrophile In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively charged, have an atom that carries ...

F⁺, is gaseous fluorine, which requires specialised equipment for manipulation. Selectfluor reagent is a salt, the use of which requires only routine procedures. Like F₂, the salt delivers the equivalent of F⁺. It is mainly used in the synthesis of

organofluorine compound Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, ...

Specialized applications

Selectfluor reagent also serves as a strong oxidant, a property that is useful in other reactions in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...

Oxidation 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 ...

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

s and

phenols In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (− O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds ar ...

. As applied to electrophilic iodination, Selectfluor reagent activates the I–I bond in I₂ molecule.

Related reagents

Similar to Selectfluor are ''N''-fluorosulfonimides: SF4Alt

References

Patents

* * * * * {{Tetrafluoroborates Reagents for organic chemistry Tetrafluoroborates Fluorinating agents Quaternary ammonium compounds Nitrogen heterocycles Chloromethyl compounds Substances discovered in the 1990s