Fluorine effect perfluoroalkyl group

A linear correlation of the oxidation potentials Bp of sulfides with Taft s a values of fluoromethy] groups is obtained as shown in Fig. 1 [42]. This dearly indicates that the polar effect of the fluoroalkyl group plays a significant role in the electron-transfer step from the sulfides to anode. Namely, the oxidation potential increases linearly as the number of fluorine atoms of the fluoroalkyl group increases. However, interestingly the oxidation potential was not appreciably affected by the length of the perfluoroalkyl group (Table 4). 

Fluorination has a particularly profound effect on the additions of nucleophiles to per-fluorinated alkenes where the intermediate is anionic. Such processes are dramatically assisted by the strongly stabilizing influence of perfluoroalkyl groups substituted at the incipient anionic site.66 Similar to carbocations (see Section 1.4.), the effect of fluorination in such systems is often ambiguous when monofluorination is involved. a-Halogens generally stabilize anions in the order bromine > chlorine > fluorine, which is the exact opposite to the inductive electron-withdrawing order of the substituents. This effect reflects the importance of l7t-repulsion.67... 

Thus the synthesis of heterocyclic compounds with one or more heteroatoms along with perfluoroalkyl groups is possible if the fluorinated molecule has a multiple bond and if an anionic center may be generated at the heteroatom or carbon atom of the functional group in intramolecular nucleophilic cyclization reactions. These new approaches point to the specific effect of fluorine atoms and to the important role of the electronic effects in... 

This kind of description allows for a similar effect to be produced by other perfluoroalkyl groups (see Table 4.4), as well as the other fluorinated groups listed. Similar conclusions to those drawn here are described in a much more detailed review and analysis [30] of results available. 

The introduction of electron-withdrawing perfluoroalkyl groups into unsaturated systems lowers frontier orbital energies [35], as deduced by theory [36] and photoelectron spectroscopy [37] for a series of fluorinated aUcenes, and manifestations of this effect are seen in much of the chemistry of such systems. 

Effects of Fluorine/ Perfluoroalkyl Groups on Chemical Reactivity... 

Braendin HP, Mabee ET (1960) Effects of adjacent perfluoroalkyl groups on carbonyl reactivity. In Stacey M, Tatlow JC, Sharp AG (eds) Advances in fluorine chemistry, vol 3. Butterworths, London,... 

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