What is the reason for the exceptional stability of the cyclopropylmethyl carbocation?

Question

Can someone explain this to me by drawing resonance structures for the cyclopropylmethyl carbocation please? Also one more question, is the tricyclopropylmethyl carbocation more stable than tropylium ion?

Answer 1

The bent bonds of the cyclopropane ring can overlap with the empty p orbital, this conjugation brings stability to cyclopropylmethyl carbocation.

Tropylium ion is more stable than tricyclopropylmethyl carbocation, because in the former compound there is less ring strain and more atoms to distribute the positive charge.