Modulating Paratropicity Strength in Diareno-Fused Antiaromatics

Abstract

Understanding and controlling the electronic structure of molecules is crucial when designing and optimizing new organic semiconductor materials. We report the regioselective synthesis of eight π-expanded diarenoindacene analogues based on the indeno[1,2-b]fluorene framework along with the computational investigation of an array of diareno-fused antiaromatic compounds possessing s-indacene, pentalene, or cyclobutadiene cores. Analysis of the experimental and computationally derived optoelectronic properties uncovered a linear correlation between the bond order of the fused arene bond and the paratropicity strength of the antiaromatic unit. The E for the pentalene and indacene core molecules correlates well with their calculated NICS values. The findings of this study can be used to predict the properties of, and thus rationally design, new diareno-fused antiaromatic molecules for use as organic semiconductors.

Steric/π‐Electronic Insulation of the carbo‐Benzene Ring: Dramatic Effects of tert‐Butyl versus Phenyl Crowns on Geometric, Chromophoric, Redox, and Magnetic Properties

“… Top: Variation of NICS(0) with calculated values of UV/Vis absorption wavelengths of highest oscillator strengths (actually the arithmetic mean over two very close excited states; see Table and Supporting Information). Bottom: Variation of the first reduction potential, E 1/2 red (Table ), versus NICS(0) by following the Haley scheme …”

“…Furthermore, by following a scheme proposed by Haley et al. for a series of antiaromatic indenofluorenes, a regular correlation is also found between the first reduction potential, E 1/2 red (Table ), and NICS(0) (Figure b). As very recently disclosed in the carbo ‐oligo(phenylene ethynylene) series, the expected qualitative correlation between E 1/2 red and the LUMO level appears to be quantitatively accurate (Figure S.6.7 in the Supporting Information).…”

Antiaromatic character of cycloheptatriene-bis-annelated indenofluorene framework mainly originated from heptafulvene segment

“…The positive values of rings A and B indicate that the BDA framework has an antiaromatic character. On the other hand, the indenofluorene core composed of rings C and D in 2(H) exhibits an aromatic character, which is in contrast with the result of pristine indenofluorene IF, in which the five-membered ring shows an antiaromatic character 33 . Since framework 2(H) contains both five- and seven-membered rings, this calculated aromatic character of the C ring is considered to result from increased electron density owing to electrical polarization between these rings.…”

Serendipitous Rediscovery of the Facile Cyclization of Z,Z‐3,5‐Octadiene‐1,7‐diyne Derivatives to Afford Stable, Substituted Naphthocyclobutadienes

“…Inclusion of the indacene subunit enhances the electron‐accepting capabilities of the molecules, leading to the examination of IFs and their congeners as possible n‐type or ambipolar organic semiconductors (OSCs) . We recently published an extensive study on closely related dinaphthoindacenes (DNIs, e. g., 13 ) and were interested in exploring their OSC performance in OFETs, which required scaling up their preparation.…”