Fluorous chemistry involves the use of

perfluorinated compounds A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound containing only carbon-fluorines and C−C bonds, as well as potentially heteroatoms. Perfluorinated compounds have properties that result from the presence of flu ...

or perfluorinated substituents to facilitate recovery of a

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

or reaction product. Perfluorinated groups impart unique physical properties including high solubility in perfluorinated solvents. This property can be useful in organic synthesis and separation methods such as

solid phase extraction Solid-phase extraction (SPE) is an extractive technique by which compounds that are dissolved or suspended in a liquid mixture are separated from other compounds in the mixture according to their physical and chemical properties. Analytical labor ...

.István T. Horváth (Ed.) Topics in Current Chemistry 2011 "Fluorous Chemistry" In practice, a perfluorinated

alkyl group In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term ''alkyl'' is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloalk ...

is incorporated into an otherwise conventional organic reagent as an

affinity tag Protein tags are peptide sequences genetically grafted onto a recombinant protein. Tags are attached to proteins for various purposes. They can be added to either end of the target protein, so they are either C-terminus or N-terminus specific or a ...

. These reagents can then be separated from organic solvents by extraction with fluorinated solvents such as perfluorohexane.

Applications

The utility of fluorous chemistry hinges on the partitioning modality distinct from polar/

non-polar In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain one or more polar ...

hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are ...

hydrophobic In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, t ...

. A major application of fluorous chemistry involves the use of

fluorosurfactant Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl mo ...

perfluorooctanoic acid Perfluorooctanoic acid (PFOA; conjugate base perfluorooctanoate; also known colloquially as C8, for its 8 carbon chain structure) is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes a ...

(PFOA) to facilitate the production of

Teflon Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...

. The technology is controversial because of the slow rates of biodegradation of such compounds.

Ponytails

In compounds exploited in academic fluorous chemistry, molecules comprise both nonfluorous and fluorous domains. The fluorous domain is often a substituent intended to confer solubility in the fluorocarbon medium. Such perfluorosubstituents are often introduced in what are called ponytails. Typical fluorous ponytails have the formula CF₃(CF₂)_n(CH₂)_m- where n is about 10 and m is about 3. Through the use of high affinity of fluorous tags (ponytails) for fluorous phases or fluorous-derivatized solid phases allows for near complete recovery of the tagged reagent (i.e., near complete reduction in a chemical waste stream), making the use of fluorous chemistry techniques a popular topic in

green chemistry Green chemistry, also called sustainable chemistry, is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances. While environmental che ...

.E.G. Hope, A.P. Abbott, D.L. Davies, G.A. Solan and A.M. Stuart "Green Organometallic Chemistry" in Comprehensive Organometallic Chemistry III, 2007, Volume 12, Pages 837-864.

Partition coefficients

The fluorous character of a molecule can be assessed by its

partition coefficient In the physical sciences, a partition coefficient (''P'') or distribution coefficient (''D'') is the ratio of concentrations of a compound in a mixture of two immiscible solvents at equilibrium. This ratio is therefore a comparison of the solub ...

between a perfluorocarbon and a hydrocarbon. In the following table, the data are for perfluoromethylcyclohexane:toluene.

Scientific Community

The International Symposium on Fluorous Technologies (ISoFT) is a biennial meeting that brings together scientists working in the area of fluorous chemistry.

References

Representative journal articles

* *{{cite journal , doi= 10.1016/j.tet.2006.08.051 , author= Zhang, W. , author2= Curran, D. P. , year= 2006 , journal=

Tetrahedron In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all th ...

, volume= 62 , issue= 51 , pages= 11837–11865 , title= Synthetic Applications of Fluorous Solid-Phase Extraction (F-SPE) , pmid= 18509513 , pmc= 2396515 Fluorine