Some other groups which might already be on the ring (for example, the -NO2 group in nitrobenzene) "push" incoming groups into the 3- position. Because inductive effects depends strongly on proximity, the meta and ortho positions of fluorobenzene are considerably less reactive than benzene. This oxygen now has a negative
The inductive effect acts like that for the carboxylate anion but in the opposite direction (i.e. Some The consideration of resonance forms is useful in this regard, since they provide a convenient means of determining the locations of these perturbations. charge on the nitrogen right next to your ring.
When both group are the same director, the third substituent depends on the stronger one. Therefore, depending on the character of the initial substituent (R), a subsequent substituent would be placed at the ortho or para position if R is an activator/halogen or at the meta position if it is a deactivator (but not a halogen). This just shows the first step of the electrophilic substitution reaction. 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. these groups are meta (m) directing.
giving that carbon a plus 1 formal charge. there because the point I'm trying to make is that the nitro These groups have a strong electron-withdrawing inductive effect (-I) either by virtue of their positive charge or because of the powerfully electronegativity of the halogens. For example, toluene, C6H5-CH3, is nitrated just choose this one right here-- those are too So this molecule down here. This happens in the presence of aluminium chloride or iron, and in the absence of UV light. And so both of those factors ring more positive, which would, of course, – All activators are ortho-para directors. A: Various functional groups are studied in organic chemistry. In the second stage, the hydrogen atom is then removed by an HSO4- ion - exactly as in the benzene case. EDGs are therefore often known as activating groups, though steric effects can interfere with the reaction.
at the last video for more details about And so let's see if
group is a deactivator, which meant that the nitrobenzene
electronegative fluorines. Electron donating groups are typically divided into three levels of activating ability (The "extreme" category can be seen as "strong".) Also, you could think about so if we look at the atom that is directly bonded 2: Thus, the nitro group is a meta directing group. Here’s a list of the ones you would most likely see: Electron Donators / Activators (strongest to weakest): -O–, -NR2, -NH2, -OH, -OR, -R, Electron Withdrawers / Deactivators (strongest to weakest): -NO2, -NR3+, -NH3+, -SO3H, -CN, -CO2H, -CO2R, -COH, -X (Halogens). How to Easily Distinguish Ortho, Meta, and Para Directors in EAS Reactions, See our previous post on the 6 Important EAS reactions to know for the DAT. Thus the overall order of reactivity is U-shaped, with a minimum at chlorobenzene/bromobenzene (relative nitration rates compared to benzene = 1 in parentheses): PhF (0.18) > PhCl (0.064) ~ PhBr (0.060) < PhI (0.12). an oxygen on the left, which now has three lone Thus, there is a weak electron-donating +I effect. a meta director. The chlorine can substitute into the ring or into the methyl group.
explanation for why the CF3 group is A second nitro group is substituted into the ring in the 3- position. Convert the given height of Statue... *Response times vary by subject and question complexity. This is a good example of a case where what is already attached to the ring can also get involved in the reaction. However, bromobenzene and iodobenzene are about the same or a little more reactive than chlorobenzene, because although the resonance donation is even worse, the inductive effect is also weakened due to their lower electronegativities.
more positive, which means it is deactivating For example, alkylation of nitro benzene gives m-alkylnitro benzene as major product. We'll have a quick look at this later on this page.  But still, all halobenzenes reacts slower than benzene itself. Upgrade your membership and get instant access to 60 practice tests, Mike's Chemistry Videos, PAT generators, the full-length test simulator, and a lot more! So you could call this