Question

Why hyperconjugation is called no bond resonance?

Answer 1

Hyperconjugation:

• Hyperconjugation is a stabilizing interaction that develops while electrons in a -bond (typically C-H or C-C) interact with a neighboring vacant or partially filled p-orbital or a -orbital, resulting in an enlarged molecular orbital that improves the system's stability.

The reason for Hyperconjugation is called no bond resonance:

• The delocalization of electrons from a single link among hydrogen and another atom in the molecule is known as hyperconjugation.
• The electrons in the bond have been delocalized. Furthermore, the hydrogen atom has no link with the other atom.
• As a result, the broken connection might be held responsible for the conjugation's feasibility.
• Hyperconjugation is also known as no bond resonance since there is no bond between the hydrogen and the other atom.
• Resonance is the delocalization of an electron from a bond pair to a lone pair or vice versa in a molecule.
  Hyperconjugation is the delocalization of $\sigma$-electrons or lone pairs of electrons into nearby p-orbitals or p$\pi$-orbitals. It happens when an orbital with a lone pair or a$\sigma$- bonding orbital overlaps with an adjacent p-orbital or $\pi$-orbital. When there are hydrogens on the $\alpha$-carbon that is next to the multiple bonds, the $\sigma$ -electrons are displaced toward the multiple bonds. The multiple bonds become polarised as a result.
• A prerequisite for hyperconjugation is the presence of a $\alpha -CH$ group, a lone pair on an atom next to a $s{p}^2$ hybrid carbon atom, or an element like nitrogen. With the aid of propene, let's examine the meaning of the term "no bond resonance" for hyperconjugation.

• Hyperconjugation is known as no bond resonance because it is clear from hyper conjugative structures 1, 2, and 3 that there is no bond between the carbon and hydrogen atoms. Since hydrogen has no bonds with other atoms, the possibility of conjugation results from the bond being broken. Where the electrons are displaced, there is no existing link. Hyperconjugation structures are more prevalent when there are more terminal hydrogen atoms.