Equiaromatic benzenoids: Arbitrarily large sets of isomers with equal ring currents

Excited state character of Cibalackrot-type compounds interpreted in terms of Hückel-aromaticity: a rationale for singlet fission chromophore design

“…Thus, the connectivity within the benzannelated units allows for tuning of E (T 1 ) by nearly 0.25 eV (6 kcal mol −1 ). There are only small variations in the E (T 1 ) between BCIBA2a and BCIBA2b , which are equiaromatic, 56 and between the three BCIBA2c–e (also equiaromatic), which likely are due to differences in the extent of steric congestion between the benzene and ketone moieties in the T 1 relative to the S 0 state.…”

Prediction of Spin Density, Baird‐Antiaromaticity, and Singlet–Triplet Energy Gap in Triplet‐State Polybenzenoid Systems from Simple Structural Motifs

“…By extension, it can be understood, and we have indeed shown, that two isomeric PBHs with the same annulation pattern will have a similar aromatic profile in the ground state, even though they are geometrically distinct. This behavior has been termed “equiaromaticity” [85] . The term was originally coined to refer to the case whereby the π‐currents of two compounds can be mapped to each other in a one‐to‐one way and was demonstrated on a collection of PBHs with distinct structural features by using graph‐theory and valence‐bond calculations.…”

The role of the long‐range exchange corrections in the description of electron delocalization in aromatic species

“…Although the nature of discrepancies between local aromaticity measures from the “response” (magnetic) and the “ground‐state” (structural and electronic) criteria in acenes can now be easily rationalized, the role of cyclic delocalization in predicting reactivity in addition reactions remains still unclear. To better understand the link between the chemical resonance and reactivity of acenes we have very recently developed a new theoretical formalism, partially based on different models of conjugated circuit currents that can be found in the literature, which allows one to predict quantitatively the relative aromatic stabilization per cycle (regardless of the selected criterion of aromaticity) as well as to evaluate the effect of the inter‐ring electron delocalization on the reactivity. The results of this study will be published elsewhere.…”