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The effect of the sigma electron displacement towards the more electronegative atom by which one end becomes positively charged and the other end negatively charged is known as the inductive effect. The - I effect is a permanent effect & generally represented by an arrow on the bond.
Morris Selig Kharasch (August 24, 1895 – October 9, 1957) was a pioneering organic chemist best known for his work with free radical additions and polymerizations.He defined the peroxide effect, explaining how an anti-Markovnikov orientation could be achieved via free radical addition. [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.
This effect was described in 1935 by John W. Baker and W. S. Nathan. [ 2 ] [ 3 ] [ 4 ] They examined the chemical kinetics for the reaction of pyridine with benzyl bromide to form a pyridinium salt, and a series of benzyl bromides having different alkyl groups as substituents at the para position.
A field effect is the polarization of a molecule through space. The effect is a result of an electric field produced by charge localization in a molecule. [1] This field, which is substituent and conformation dependent, can influence structure and reactivity by manipulating the location of electron density in bonds and/or the overall molecule. [2]
If a positive charge is brought near a nonconductive object, the electrons in each molecule are attracted toward it, and move to the side of the molecule facing the charge, while the positive nuclei are repelled and move slightly to the opposite side of the molecule. Since the negative charges are now closer to the external charge than the ...
It was developed by Robert W. Taft in 1952 [2] [3] [4] as a modification to the Hammett equation. [5] While the Hammett equation accounts for how field, inductive, and resonance effects influence reaction rates, the Taft equation also describes the steric effects of a substituent. The Taft equation is written as:
The most dominant effect is clear when looking at the ratio of R to F. For example, a tungsten complex was shown to alkylate allyl carbonates A and B. The ratio of products A1 and B1 can be attributed to the para substituent, X (Fig. 3). Using Swain–Lupton parameters (σ = 0.2F + 0.8R) a ρ value of -2.5 was found to be the slope.