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Trifluoromethyl group covalently bonded to an R group. The trifluoromethyl group is a functional group that has the formula-CF 3. The naming of is group is derived from the methyl group (which has the formula -CH 3), by replacing each hydrogen atom by a fluorine atom. Some common examples are trifluoromethane H– CF 3, 1,1,1-trifluoroethane H ...
In the CF 3 radical the fluorine atom is an electron-withdrawing group via the inductive effect but also a weak pi donor through interaction of the fluorine lone pair with the radical center's SOMO. Compared to the methyl radical the CF 3 radical is pyramidal (angle 107.8 °C ) with a large inversion barrier, electrophilic and also more reactive.
The trifluoromethyl cation is a molecular cation with a formula of CF + 3. It is a carbocation due to its positively charged carbon atom. It is part of the family of carbenium ions, with three fluorine atoms as substituents in place of its hydrogen atoms. [1]
Electron-withdrawing groups exert an "inductive" or "electron-pulling" effect on covalent bonds. The strength of the electron-withdrawing group is inversely proportional to the pKa of the carboxylic acid. [2] The inductive effect is cumulative: trichloroacetic acid is 1000x stronger than chloroacetic acid.
In this usage, a leaving group is a less formal but more commonly used synonym of the term nucleofuge. In this context, leaving groups are generally anions or neutral species, departing from neutral or cationic substrates, respectively, though in rare cases, cations leaving from a dicationic substrate are also known. [3]
TFA is a stronger acid than acetic acid, having an acid ionisation constant, K a, that is approximately 34,000 times higher, [3] as the highly electronegative fluorine atoms and consequent electron-withdrawing nature of the trifluoromethyl group weakens the oxygen-hydrogen bond (allowing for greater acidity) and stabilises the anionic conjugate ...
The effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant resonance structures and is symbolized by the letter M. [2] The mesomeric effect is negative ( –M ) when the substituent is an electron-withdrawing group , and the effect is positive ( +M ) when the ...
An electron withdrawing group (EWG) will have the opposite effect on the nucleophilicity of the ring. The EWG removes electron density from a π system, making it less reactive in this type of reaction, [ 2 ] [ 3 ] and therefore called deactivating groups .