Since NO2 is an electron withdrawing group, a glance at the resonance structures shows that the positive charge becomes concentrated at the ortho-para positions. Thus these positions are deactivated towards electrophilic aromatic substitution. Hence, NO2 is a meta-director, as we all learned in organic chemistry..
Herein, is nitrobenzene meta directing group?
Yes, Nitro-group is meta-directing. The nitro group strongly deactivates the benzene ring towards electrophilic substitution. Nitro group is electron withdrawing group and thus causes electron deficiency at ortho and para positrons as is clear from the resonating structures of nitro benzene.
Subsequently, question is, what makes a substituent an ortho para directing group versus a meta directing group? If the opposite is observed, the substituent is called a meta directing group. Ortho, para directing groups are electron-donating groups; meta directing groups are electron-withdrawing groups. The halide ions, which are electron-withdrawing but ortho, para directing, are the exception.
Then, what is a meta directing group?
E+ = electrophile. If the relative yield of the ortho product and that of the para product are higher than that of the meta product, the substituent on the benzene ring in the monosubstituted benzene is called an ortho, para directing group. If the opposite is observed, the substituent is called a meta directing group.
Why nitro group is deactivating and meta directing?
Deactivating groups that either do not donate electrons by resonance (sulfonic acid groups and ammonium ion groups) or actually withdraw electrons by resonance (carbonyl, nitrile and nitro groups) are meta-directing. Instead, they destabilize the intermediates for o,p-substitution relative to the meta intermediate.
Related Question Answers
Why is nitrobenzene deactivating?
As seen above, the molecule has partial positive charge on ortho and para- positions. So, with respect to the benzene molecule, the benzene ring has lesser electron density as a whole. Hence nitrobenzene is deactivated towards electrophilic attack. Hence nitrobenzene is deactivated towards electrophilic attack.What is meta directing effect?
Meta-directing: Substituents which draw electron density from the ortho and para positions, hence increasing reaction on the meta position. Donation or withdrawal of electrons can occur via either a conjugative or an inductive effect.Why is no2 a meta director?
Since NO2 is an electron withdrawing group, a glance at the resonance structures shows that the positive charge becomes concentrated at the ortho-para positions. Thus these positions are deactivated towards electrophilic aromatic substitution. Hence, NO2 is a meta-director, as we all learned in organic chemistry.Why is nitro group a meta director?
The electron density is more heavily removed from the positions ortho and para to the nitro group than the position meta to the nitro group. Drawing resonance structures makes this clear. Therefore, nitro groups are meta directing, as only the meta positions can be nucleophilic enough to attack an electrophile.What is a meta director?
Meta director: In electrophilic aromatic substitution, a substituent that favors electrophilic attack meta to the substituent. Most meta directors are also deactivators. Bromination of nitrobenzene gives meta-bromonitrobenzene as the major product because the nitro group is a meta director.Is no2 an electron withdrawing group?
Substituents with pi bonds to electronegative atoms (e.g. -C=O, -NO2) adjacent to the pi system are electron withdrawing groups (EWG) - they deactivate the aromatic ring by decreasing the electron density on the ring through a resonance withdrawing effect.Why meta position is stable than Ortho?
Why? In this resonance form, all of the carbon atoms have a full octet of electrons. That's because the oxygen directly bonded to the ring can donate a lone pair to the adjacent carbocation, forming a pi bond. This makes the meta- carbocation intermediate much less stable than the ortho- carbocation intermediate.Is och3 an electron withdrawing group?
Again, hyper-conjugation explains the additional electron withdrawing power of the para-trifluoromethyl group. b) -OCH3 (methoxy group) The methoxy group is electron withdrawing by the inductive effect of the oxygen atom, since the electronegativity of oxygen is 2.6. This is reflected in the positive value for σm.Why are halogens deactivating?
Halogens bonded to benzene ring has three lone pairs. These three electron pairs can cause resonance in benzene ring. But, halogens are also highly electronegative and thus they have strong -I effect. So, they are deactivating groups.Is COOH a meta director?
The group which directs the second incoming group to the meta position, is called a meta-director. For example, alkylation of nitro benzene gives m-alkylnitro benzene as major product. -NO2, -CHO, -COOH, COOR, –SO3H, -CN, -COR etc.Is aldehyde a meta director?
meta- Directors. Examples of meta– directors include nitriles, carbonyl compounds (such as aldehydes, ketones, and esters), sulfones, electron-deficient alkyl groups, nitro groups, and alkylammoniums. Specific example: nitration of trifluoromethylbenzene gives the meta product in about 90% yield.Why halogens are deactivating but ortho para directing?
Halogens are very electronegative. This means that inductively they are electron withdrawing. However, because of their ability to donate a lone pair of electrons in resonance forms, they are activators and ortho/para directing. Electron withdrawing groups are meta directors and they are deactivators.Is aldehyde activating or deactivating?
1 Answer. A carbonyl group such as an aldehyde is a deactivating group as it withdraws electron density by both the inductive effect (through the sigma bonds) and the resonance effect which involves pi systems.Why benzoic acid is meta directing?
In the case of Benzoic acid, since the -COOH group is an electron withdrawing group, because of resonance(-M effect), the carbon atoms at the ortho and para positions get a positive charge. Thus, the incoming electrophile is directed towards the meta positions. Similarly, -CHO group is an electron withdrawing group.Why Anilinium is meta directing?
solution.It is because in anilinium ion lone pair of electrons gets involved in formation of bond with hydrogen because of which the molecule will not exert electromeric or mesomeric effect rather than it will exert a stong – I effect due to the presence of a positive charge to give mainly m-substituted product.Are esters activating or deactivating?
It clearly shows that ester (CO2R) is a DEACTIVATING group. However, these are all ACTIVATING because the oxygen is partially negatively charged due to the polarity difference. This negative charge will donate electron density to the ring, and therefore they are activating.Is och3 a meta director?
Experiments show us that they are ortho-para directors. So the fact that they can contribute to resonance (like OCH3) is what stabilizes the ortho-para products relative to meta. (Halogens are the weird exception: they slow down aromatic substitution, but favor ortho-para products).Is Para more stable than Ortho?
Ortho nitrotoluene is more reactive than para nitrotoluene towards Electrophilic Substitution reaction(therefore being less stable) the reason being that though both Ortho and para directing groups are activating groups(i.e they increase reactivity of the compound towards the above reaction) para position is lessIs so3h an ortho para director?
Type 1- All groups having a lone pair at the key atom are ortho, para-directing groups. Type 2- All groups having their key atom multiply bonded to more powerful element are meta--directing groups. For example, -NO2, -CN, -COOH, -COR,-SO3H etc. Type 3- Alkyl groups are ortho, para-directing groups. 
John Campbell 
