Nitro group electronic effects

Electronic spectra of the nitro groups Solvent effect... 

Para Nitro Group - Electronic Influence on R is due to Inductive and Resonance Effects... 

By comparing the conversions of la and lb, it was clear that lb generated more O2 than la. The NO2 group attributed to the efficient formation of O2. The reaction of lb was slower than that of la due to the electron-attracting effect of nitro group. The effect of N(CH3)2 group had been studied in our lab. Ic was unfavorable to the formation of 2 and more efficient chemiluminescent system than la. ... 

If we examine Table 21.1, we see that phenols having electron-withdrawing groups (Cl— or O2N—) attached to the benzene ring are more acidic than phenol itself. Account for this trend on the basis of resonance and inductive effects. Your answer should also explain the large acid-strengthening effect of nitro groups, an effect that makes 2,4,6-trinitrophenol (also called picric acid) so exceptionally acidic (pA a = 0.38) that it is more acidic than acetic acid = 4.76). 

A nitro group behaves the same way m both reactions it attracts electrons Reaction is retarded when electrons flow from the aromatic ring to the attacking species (electrophilic aromatic substitution) Reaction is facilitated when electrons flow from the attacking species to the aromatic ring (nucleophilic aromatic substitution) By being aware of the connection between reactivity and substituent effects you will sharpen your appreciation of how chemical reactions occur... 

Nucleophilic Displacement Reactions. The strong electron-withdrawing effect of a trifluoromethyl group activates ortho and para halogen toward nucleophilic attack. Such chlorine labiUty is utili2ed in the manufacture of crop control chemicals containing trifluoromethyl and nitro groups. 

Much of the reactivity shown by the ring atoms and substituents of pyrimidine is akin to that of the corresponding parts of 1,3-dinitrobenzene and 3-nitropyridine. This arises from the quantitatively similar electron-withdrawing effects of doubly-bound ring nitrogen atoms and of nitro groups in reducing sharply the aromaticity of the cyclic system. 

The effect of the bond dipole associated with electron-withdrawing groups can also be expressed in terms of its interaction with the cationic u-complex. The atoms with the highest coefficients in the LUMO 3 are the most positive. The unfavorable interaction of the bond dipole will therefore be greatest at these positions. This effect operates with substituents such as carbonyl, cyano, and nitro groups. With ether and amino substituents, the unfavorable dipole interaction is overwhelmed by the stabilizing effect of the lone-pair electrons stabilizing 3. 

As to the electron-withdrawing substituents, the activating effect of a nitro group in the piperidino-dechlorination of 2-chloropyridine involves factors of 7.3 x 10 and 4.6 x 10 from the para and ortho positions, respectively. An ortho-cyano group was found to be... 

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