Naslov
Towards understanding π-stacking interactions between non-aromatic rings

Autori
Molčanov, Krešimir ; Kojić-Prodić, Biserka

Izvornik
IUCrJ (2052-2525) 6 (2019), 2; 156-166

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, pregledni rad, znanstveni

Ključne riječi
π-stacking interactions ; non-aromatic rings ; multicentric bonding ; charge density

Sažetak
The first systematic study of π-interactions between non-aromatic rings, based on the authors’ own results from an experimental X-ray charge-density analysis assisted by quantum chemical calculations, is presented. The landmark (nonaromatic) examples include quinoid rings, planar radicals and metal-chelate rings. The results can be summarized as: (i) non-aromatic planar polyenic rings can be stacked, (ii) interactions are more pronounced between systems or rings with little or no π-electron delocalization (e.g. quinones) than those involving delocalized systems (e.g. aromatics), and (iii) the main component of the interaction is electrostatic/multipolar between closed-shell rings, whereas (iv) interactions between radicals involve a significant covalent contribution (multicentric bonding). Thus, stacking covers a wide range of interactions and energies, ranging from weak dispersion to unlocalized two-electron multicentric covalent bonding (‘pancake bonding’), allowing a face-to-face stacking arrangement in some chemical species (quinone anions). The predominant interaction in a particular stacked system modulates the physical properties and defines a strategy for crystal engineering of functional materials.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA