The carbon–fluorine chemical bond is the strongest bond in organic chemistry, which is one of the most important factors contributing to the great stability of the organic fluorinated compounds. Fluorine is unique in that it is possible to replace hydrogen by fluorine in organic compounds without gross distortion of the geometry of system. The applications of fluorine-containing organic compounds span virtually the whole range of the chemical and life science and it is quite clear that wherever organic chemistry, biochemistry and chemical industry progress, organic fluorinated compounds will play an important role.
Applications
Biological chemistry: Organic fluorinated compounds are commonly applied in pharmaceuticals as they increase the stability of the carbon framework; besides this, the relatively small size of fluorine is convenient. The introduction of fluoro-carbon bond can improve the chance of having a success drug by a factor of ten. It is estimated that 20% of the drugs and 30-40% of the agrichemicals are organic fluorinated compounds. Examples include 5-fluorouracil, fluoxetine, paroxetine, ciprofloxacin, mefloquine and fluconazole.
Material chemistry: Organic fluorinated compounds have many applications in the field of material chemistry. Fluid fluoropolymers with a low coefficient of friction are used as specialty lubricants. Fluorocarbon-based greases are used in demanding applications and the representative products include Fomblin and Krytox. Organic fluorinated compounds are used in fire-fighting foams for its non-flammability and are components of liquid crystal displays. The polymer analog of trifluoromethanesulfonic acid is solid acid used as membrane in most low temperature fuel cells. Bifunctional monomer 4,4'-Difluorobenzophenone is a precursor of PEEK-grade polymers.
Transition metal chemistry: Organic fluorinated compounds have been featured in organometallic and coordination chemistry. One advantage of F-containing ligands is the convenience of 19F NMR spectroscopy for monitoring the reaction. Organic fluorinated compounds can be used as "sigma donor ligands," as shown for the titanium(III) derivative [(C5Me5) 2Ti (FC6H5)] BPh4. And fluorocarbon substituents are most often used to enhance the Lewis acidity of the metal center. A prime example is "Eufod," a coordination complex of europium(III) characterized by perfluoroheptyl-modified acetylacetone ligand, which is useful in organic synthesis and also as transfer reagents in NMR spectroscopy. In the overlap field of coordination chemistry and material science, the fluorination of organic ligands is used to tune the properties of the molecules. For example, the degree of fluorination of metallized 2-phenylpyridine ligands in platinum (II) complexes significantly influences the emissive properties of the complexes.
