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An electron donating group (EDG) or electron releasing group (ERG, Z in structural formulas) is an atom or functional group that donates some of its electron density into a conjugated π system via resonance (mesomerism) or inductive effects (or induction)—called +M or +I effects, respectively—thus making the π system more nucleophilic.
Delocalizing the radical ion stabilizes the transition state structure. As a result, the energy of activation decreases, enhancing the rate of the overall reaction. According to the captodative effect, the rate of a reaction is the greatest when both the EDG and EWG are able to delocalize the radical ion in the transition state structure. [7]
The EWG withdraws electron density by resonance and effectively stabilizes the negative charge that is generated. The corresponding plot will show a positive rho value. In the case of a nucleophilic acyl substitution the effect of the substituent, X, of the non-leaving group can in fact accelerate the rate of the nucleophilic addition reaction ...
Longtime "Today" show weatherman Al Roker also made an appearance via video to congratulate Melvin on the new role. "I knew this day would come. "I knew this day would come. I've watched you grow.
Melvin, 45, got his start in high school as a teen correspondent at WIS-TV, ... The Today show airs weekdays on NBC beginning at 7 a.m. ET. Read the original article on People.
Select your favorite television father in TODAY Show's TV Dad bracket. Tune in each day for the full breakdown of the bracket results.
Officially launched as The National Today Show, [1] Today is Australia's longest running morning breakfast news program. [2] The show premiered on 28 June 1982. The original hosts, Steve Liebmann and Sue Kellaway , spent four years together before Liebmann left to present the evening news for Network Ten in Sydney.
"At first I was like, 'Oh, this is so sweet.' And then, I realized that was her passive-aggressive way of saying, 'Please get your candle crap out of the kitchen. It's taking over,'" Melvin teases.