Electronic absorption spectroscopy of polycyclic aromatic hydrocarbons (PAHs) radical cations generated in oleum: A superacid medium

Cataldo, Franco; Iglesias‐Groth, Susana; Manchado, A.

doi:10.1016/j.saa.2010.08.037

Cited by 25 publications

(18 citation statements)

References 32 publications

(51 reference statements)

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“…TheU V/Vis/NIR absorption spectrum of this green solution exhibited broad absorption bands between 700-900 nm, and is similar to the reported data for radical cations of tetracene. [16] Furthermore, almost the same absorption spectrum was obtained by oxidation of as olution of 3 in CH 2 Cl 2 at room temperature with the one-electron oxidant tris(4-bromophenyl)aminium hexachloroantimonate (Magic Blue,1 .0 equiv; [17] Figure 6). These results indicate that although the generation of radical cation 3C + was most likely mediated by DDQ/MeSO 3 H, it did not lead to the formation of 4.…”

mentioning

confidence: 59%

Unsymmetric Twofold Scholl Cyclization of a 5,11‐Dinaphthyltetracene: Selective Formation of Pentagonal and Hexagonal Rings via Dicationic Intermediates

Chaolumen¹,

Murata

Wakamiya³

et al. 2017

Angew Chem Int Ed

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Even though the Scholl reaction is one of the most powerful processes for the synthesis of polycyclic aromatic hydrocarbons (PAHs), its mechanism still remains a subject of discussion. Herein, we report a unique twofold Scholl cyclization of a 5,11-dinaphthyltetracene. Single-crystal X-ray diffraction analysis of the cyclization product revealed that unsymmetric cyclizations of the two naphthyl groups resulted in the formation of fully unsaturated pentagonal and hexagonal rings. The thus obtained product exhibits a twisted π-surface and an absorption band that reaches up to 950 nm. A combined experimental and theoretical study showed that such unsymmetric Scholl cyclizations can be rationalized in terms of a mechanism that involves dicationic intermediates, which stands in contrast to previously reported pathways based on radical cations and arenium ions.

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mentioning

confidence: 59%

Unsymmetric Twofold Scholl Cyclization of a 5,11‐Dinaphthyltetracene: Selective Formation of Pentagonal and Hexagonal Rings via Dicationic Intermediates

Chaolumen¹,

Murata

Wakamiya³

et al. 2017

Angew Chem Int Ed

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“…Again, this is typical of a quinoidal PCH radical anion where the skeletal backbone has regained partial aromaticity. 39,40 With increasing cathodic potential, a clear progression to DIAn 2− is observed, with new peaks at 330 nm and typical rigid acene absorbance from 440 to 470 nm. These anthracene-like vibronic features are in good agreement with those of the dihydro precursor of DIAn that also contains an aromatic anthracene core appended by saturated indeno fragments (Figure S4).…”

Section: ■ Introductionmentioning

confidence: 98%

A Biradical Balancing Act: Redox Amphoterism in a Diindenoanthracene Derivative Results from Quinoidal Acceptor and Aromatic Donor Motifs

et al. 2016

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The reduced and oxidized states of an open-shell diindeno[b,i]anthracene (DIAn) derivative have been investigated by experimental and theoretical techniques. As a result of moderate biradical character and the ability of cyclopenta-fused scaffolds to stabilize both positive and negative charges, DIAn exhibits rich redox chemistry with four observable and isolable charged states. Structural and electronic properties of the DIAn system are brought to light by UV-vis-NIR and Raman spectroelectrochemical measurements. Aromatization of the diindeno-fused anthracene core upon successive single-electron injections is revealed through single-crystal X-ray diffraction of radical anion and dianion salts. We present a rare case where the pseudoaromatic/quinoidal ground state of a neutral biradical polycyclic hydrocarbon leads to a stable cascade of five redox states. Our detailed investigation of the transformation of molecular structure along all four redox events provides a clearer understanding of the nature of charge carriers in ambipolar organic field-effect transistors.

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“…This absorption is similar to that seen for the aromatic radical cation of dicoronylene. [31] We see similar long-wavelength features when trifluoroacetic acid ( Figure S2A in the Supporting Information) or HBr gas are used in solution. We did not detect these long-wavelength absorbances in films that were exposed to trifluoroacetic acid ( Figure S2C in the Supporting Information), but we detected the protonation through OFET measurements described below.…”

Section: Dedicated To Sandra Turromentioning

confidence: 60%

Controlled Doping in Thin‐Film Transistors of Large Contorted Aromatic Compounds

et al. 2013

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Electronic absorption spectroscopy of polycyclic aromatic hydrocarbons (PAHs) radical cations generated in oleum: A superacid medium

Cited by 25 publications

References 32 publications

Unsymmetric Twofold Scholl Cyclization of a 5,11‐Dinaphthyltetracene: Selective Formation of Pentagonal and Hexagonal Rings via Dicationic Intermediates

Unsymmetric Twofold Scholl Cyclization of a 5,11‐Dinaphthyltetracene: Selective Formation of Pentagonal and Hexagonal Rings via Dicationic Intermediates

A Biradical Balancing Act: Redox Amphoterism in a Diindenoanthracene Derivative Results from Quinoidal Acceptor and Aromatic Donor Motifs

Controlled Doping in Thin‐Film Transistors of Large Contorted Aromatic Compounds

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