# Possibility of π–π stacking in non-aromatic systems

Is it possible to have π–π stacking for non-conjugated double bond systems?

For example, can the carbonyl groups of two urea molecules participate in π–π stacking? Although urea prefers to stay in hydrogen bonded form.

I would be really happy if you cite some resources (research paper, book, etc.) while answering.

• There's quite a conjugation in urea. – Mithoron Sep 9 '17 at 19:50
• What you describe would be something very different than ordinary pi-stacking, just like hydrogen bonding is not a simple polar interaction. – Karl Sep 9 '17 at 20:03
• en.wikipedia.org/wiki/… – Mithoron Sep 9 '17 at 21:50
• @Mithoron I did not want some other type of interaction. I just wanted to know if it possible to have $\pi$ - $\pi$ stacking in non-conjugated systems. – Mitradip Das Sep 11 '17 at 6:10
• It is possible in non-aromatic molecules , but p orbitals are needed. See the answer to this question. chemistry.stackexchange.com/questions/60055/… – porphyrin Sep 11 '17 at 14:27