Lateral Extension of π Conjugation along the Bay Regions of Bisanthene through a Diels–Alder Cycloaddition Reaction

Abstract

Diels-Alder cycloaddition reactions at the bay regions of bisanthene (1) with dienophiles such as 1,4-naphthoquinone have been investigated. The products were submitted to nucleophilic addition followed by reductive aromatization reactions to afford the laterally extended bisanthene derivatives 2 and 3. Attempted synthesis of a larger expanded bisanthene 4 revealed an unexpected hydrogenation reaction at the last reductive aromatization step. Unusual Michael addition was observed on quinone 14, which was obtained by Diels-Alder reaction between 1 and 1,4-anthraquinone. Compounds 1-3 exhibited near-infrared (NIR) absorption and emission with high-to-moderate fluorescent quantum yields. Their structures and absorption spectra were studied by density function theory and non-planar twisted structures were calculated for 2 and 3. All compounds showed amphoteric redox behavior with multiple oxidation/reduction waves. Oxidative titration with SbCl(5) gave stable radical cations, and the process was followed by UV/Vis/NIR spectroscopic measurements. Their photostability was measured and correlated to their different geometries and electronic structures.

Reductive Aromatization/Dearomatization and Elimination Reactions to Access Conjugated Polycyclic Hydrocarbons, Heteroacenes, and Cumulenes

“…ChemPlusChem 2017, 82,967 -1001 www.chempluschem.org and 100, [145] as well as anthracenes 101 [135] and 102 [146] -the latter used as ap recursor for ab lue OLED emitter.A lso of interest are two-dimensional acenes, such as bisanthene 103 [147] and laterally extended bisanthenes, ac lass of compounds that exhibit small band gaps andnear-IR absorption (Figure 9). [148] There are relativelyf ew reports of this reduction method, probablyd ue to moderate yields and by-product formation found in most of the reported examples. [11f,32d, 130, 149] For instance,depending on the substitution pattern of the precursor, the use of KI can lead to 1,4-shift products such as 9-anthrones (Scheme 42).…”

Polycyclic Aromatic Hydrocarbons as Potential Building Blocks for Organic Solar Cells

“…However, periacene derivatives tend to oxidize rapidly as a consequence of a relatively high diradical character. Even relatively small or annulated periacenes that exhibit good stability under ambient conditions suffer from relatively poor photostability, making them unsuitable for OSC applications …”

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