Polycyclic Hydrocarbons from [4n]Annulenes: Correlation versus Hybridization Forces in the Formation of Diradicaloids. (14th September 2022)

• Record Type: Journal Article
• Authors: Moles Quintero, Sergio; Haley, Michael M.; Kertesz, Miklos; Casado, Juan
• Is Part Of: Angewandte Chemie. Volume 134:Number 44(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-14
• Subjects: annulenes -- antiaromaticity -- diradical character -- electron correlation -- hybridization energy; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202209138
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The conceptual connections between [4 n ] Hückel antiaromaticity, disjoint orbitals, correlation energy, pro‐aromaticity and diradical character for a variety of extended π‐conjugated systems, including some salient recent examples of nanographenes and polycyclic aromatic radicals, are provided based on their [4 n ]annulene peripheries. The realization of such structure–property relationships has led to a beneficial pedagogic exercise establishing design guidelines for diradicaloids. The antiaromatic fingerprint of the [4 n ]annulene peripheries upon orbital interactions due to internal covalent connectors gives insights into the diradicaloid property of a diversity of π‐conjugated molecules that have fascinated chemists recently. Abstract : A conceptual electronic structure trip from [4 n ] Hückel antiaromatics to diradicaloids and to more hierarchical complex molecular shapes made by internal covalent hybridization of the peripheral [4 n ] π‐electron circuit is described. Focus is on the underlying physical organic chemistry implications.