activating groups-deactivating groups-definition-list-application

·        activating groups explain with an example

Activating groups are some chemical constituents which increase the electron 

density of benzene ring owing to their positive mesomeric effect and inductive effect.

In other words, there are some groups in organic chemistry, which have electron 

donating ability and they can activate the benzene ring through increasing the electron density of benzene ring, are called activating groups.

Since these type of groups activate the benzene ring, so they are called activator enhancer or activating groups. Activating groups are also called electron donating group.

Most of the activating groups contain one or more lone pair of electron.This lone pair of electron participate in resonance with the pi electron of benzene ring.

As a result, benzene ring with activating  groups become electron rich.That is, benzene ring acts as a source of electrons.

Therefore, benzene ring with activating group becomes more reactive towards   electrophilic substitution reaction than benzene ring without activating groups.

·        Activating groups list.

There are three types of activating groups are known in organic chemistry,  namely, strong activating groups, medium activating groups and weak activating groups.

Activating groups list of these three type are shown below.

·        Why are activating groups also called ortho, para directing groups ?

Activating groups increase the electron density of benzene ring due to their +I and +M effect.

It has been found that, owing to presence of activating groups, the density of electron increase basically, on the ortho and para carbon atom of the ring.

So, in electrophilic substitutionreaction, the electrophile attack on ortho and para carbon atom only.

 Hence, activating groups which are already present in the benzene ring, indicate the incoming group to take the ortho and para position of the ring.

For example,  nitration of phenol gives ortho and para nitro phenol.

That is, the –OH group of phenol which already exist in benzene ring , is ortho and para directing.

Similarly, chlorination of toluene, gives ortho and para chloro toluene . So, –CH₃ group is also a ortho and para directing group.

Although, in both cases, para product is predominant than ortho product,  due to steric hindrance in ortho position.

For the above reason, activating groups are also called ortho, para directing groups.

·        deactivating groups explain with an example

Deactivating groupsare those groups which decrease the electron density of benzene ring owing to their –I effect as well as –M effect.

In other words, there are some groups in organic chemistry, which have electron 

accepting ability and they deactivate the benzene ring through reducing  the electron density of benzene ring, are called deactivating groups.

Since these type of groups deactivate the benzene ring, so they are called activator reducer or deactivating groups.

Deactivating groups are also called electron withdrawing  group.

·        Deactivating groups list.

There are three types of deactivating groups are known in organic chemistry, 

namely, strong deactivating groups, medium deactivating groups and weak deactivating groups.
Dectivating groups list of these three type are shown below.

·        Why are deactivating groups also called meta-directing groups ?

Deactivating groups are also called electron with drawing  groups.

The – I effect of deactivating groups reduce the electron density from all the position of benzene ring.

But, owing to –R effect of deactivating group, the electron density reduces, basically from ortho and para position.

So, the density of electron at meta position remain comparatively more than ortho and para position.

Hence, in electrophilic substitution reaction, the electrophile attack on meta position only.

For example,  nitration of benzaldehyde gives meta nitro benzaldehyde.

That is, the –CHO group of benzaldehyde which already exist in benzene ring , is meta directing.

Similarly, nitration of acetophenon, gives meta nitro acetophenon. So, –COCH₃ group is also a meta directing group.

For the above reason, deactivating groups also called meta-directing groups.

·        activating groups in aromatic electrophilic substitution.

·        activating groups explain with an example

·        Activating and deactivating groups list.

·        Why are activating groups also called ortho,para directing groups ?

·        Why are deactivating groups also called meta-directing groups ?

·        Is methoxy group is ortho, para directing ?

Oxidizing power of Xenon fluorides.