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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 electrophilic aromatic substitution reactions, existing substituent groups on the aromatic ring influence the overall reaction rate or have a directing effect on positional isomer of the products that are formed. An electron donating group (EDG) or electron releasing group (ERG, Z in structural formulas) is an atom or functional group that ...
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.
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.
6 followed by reaction with an electron-rich arene. Now the reaction of the source of the cation [clarification needed] usually uses 5-(trifluoromethyl)dibenzothiophenium tetrafluoroborate as the reagent. [3] One of the active reagents for making the cation.
The mesomeric effect is negative (–M) when the substituent is an electron-withdrawing group, and the effect is positive (+M) when the substituent is an electron donating group. Below are two examples of the +M and –M effect. Additionally, the functional groups that contribute to each type of resonance are given below.
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 ...