Inductive and Mesomeric Effect

The inductive effect and mesomeric effect are two types of electron displacement in organic molecules. The inductive effect is a permanent electron displacement due to the difference in electronegativity of atoms. The mesomeric effect is a temporary electron displacement due to the delocalization of electrons in a molecule.

Inductive Effect

The inductive effect is the permanent displacement of electrons in a molecule due to differences in electronegativity of atoms. The electronegativity of an atom is its ability to attract electrons towards itself in a chemical bond. The inductive effect is transmitted through sigma bonds and decreases with distance from the source atom.

There are two types of inductive effect:

1. Positive Inductive Effect
When a less electronegative atom is attached to a carbon atom, it donates its electron density to the carbon atom, resulting in a positive inductive effect.

2. Negative Inductive Effect
When a more electronegative atom is attached to a carbon atom, it withdraws electron density from the carbon atom, resulting in a negative inductive effect.

Mesomeric Effect

The mesomeric effect is the temporary displacement of electrons in a molecule due to the delocalization of electrons in a molecule. This effect is transmitted through pi bonds and is not limited by distance.

There are two types of mesomeric effect:

1. Electron donating Mesomeric Effect
When a substituent group donates electron density towards the pi bond, it results in an electron donating mesomeric effect.

2. Electron withdrawing Mesomeric Effect
When a substituent group withdraws electron density from the pi bond, it results in an electron withdrawing mesomeric effect.

Conclusion

The inductive and mesomeric effects are two types of electron displacement in organic molecules. The inductive effect is a permanent electron displacement due to the difference in electronegativity of atoms. The mesomeric effect is a temporary electron displacement due to the delocalization of electrons in a molecule.