Are <i>N</i>,<i>N</i>-Dihydrodiazatetracene Derivatives Antiaromatic?

Miao, Shaobin; Brombosz, Scott M.; Schleyer, Paul v. R.; Wu, Judy I.; Barlow, Stephen; Marder, Seth R.; Hardcastle, Kenneth I.; Bunz, Uwe H. F.

doi:10.1021/ja077614p

Cited by 170 publications

(155 citation statements)

References 43 publications

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“…2 it is not the X-ray crystal structure of 5 but of the butterfly-cycloaddition product 6. This is an unusual observation, as azatetracenes are normally stable and isolable without observation of any cycloaddition products, both substituted as well as unsubstituted cores as demonstrated in earlier works [9]. We interpret this result in that the two 2,3-TIPS-ethynyl groups orient the molecules of 5 in the solid state such that they immediately form the butterfly dimer by evading steric interaction of the two large substituents.…”

Section: Resultssupporting

confidence: 74%

Synthesis of tetraazatetracenes and -pentacenes: role of the substituents for their stability

Märken

Lindner

Appleton

et al. 2014

Pure and Applied Chemistry

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We report the synthesis of a series of novel tetraazaacene derivatives and compare their stability with respect to size, oxidation potential and position of the TIPS-ethynyl groups. The latter has the most pronounced effects on the stability. In case of azatetracenes where TIPS-alkynes are either attached laterally or in the peri-positions, the former ones dimerized while the latter are stable. Attempts to expand this concept to the corresponding tetrakis-peri-substituted heptacenes led to the isolation of the dimerized butterfly product.

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Section: Resultssupporting

confidence: 74%

Synthesis of tetraazatetracenes and -pentacenes: role of the substituents for their stability

Märken

Lindner

Appleton

et al. 2014

Pure and Applied Chemistry

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“…[13] The direct formation of azatetracenes by deploying ortho-quinones worked well, but for azapentacenes yields were variable. [14] Very recently,Z hang and co-workers synthesized hexaazapentacenesb yc ondensation of tetraaminophenazinew ith various diketones. [15] Av ariant of this condensation (Scheme 2) is the nucleophilic reactiono ft he diamine 12 in the presence of sodium amide with hexafluorobenzene to give the tautomerized N,N'-dihydro compound 13 in 24 %y ield.…”

Section: Classic Syntheses Of Azaacenesmentioning

confidence: 99%

The Palladium Way to N‐Heteroacenes

Bunz

Engelhart

2016

Chemistry A European J

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Novel synthetic methodologies allow increasingly efficient access to known organic materials, as well as the preparation of otherwise inaccessible species. Pd-catalyzed coupling of aromatic dihalides to ortho-diaminoarenes furnishes embedded stable N,N'-dihydropyrazines expediently and in often excellent yields. The embedded N,N'-dihydropyrazines can then be oxidized by MnO2 to give substituted azatetracenes, azapentacenes, azahexacenes, and azaheptacenes, which are soluble, processable, and stable. This powerful Pd-catalyzed methodology allows the preparation of azaacenes, including diaza-, tetraaza- and hexaazaacenes. In combination with a suitable Pd precursor, Buchwald-type biarylphosphines have been shown to give excellent results. Activated dihalides such as 2,3-dihaloquinoxalines are coupled easily under simplified conditions, whereas 2,3-dibromoacenes require more stringent conditions and advanced catalyst precursors. Pd catalysts effect the assembly of azaacenes with otherwise difficult to obtain substitution patterns. High yields and flexibility make this method most attractive.

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“…2a) with 10b gave tetrachlorodiazatetracene 11b smoothly and in good yields. For comparison purposes we also re-synthesized 11a 23 . The diamine 13 (Fig.…”

Section: Synthesismentioning

confidence: 99%

Effects of electronegative substitution on the optical and electronic properties of acenes and diazaacenes

et al. 2010

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Large acenes, particularly pentacenes, are important in organic electronics applications such as thin-film transistors. Derivatives where CH units are substituted by sp 2 nitrogen atoms are rare but of potential interest as charge-transport materials. In this article, we show that pyrazine units embedded in tetracenes and pentacenes allow for additional electronegative substituents to induce unexpected redshifts in the optical transitions of diazaacenes. The presence of the pyrazine group is critical for this effect. The decrease in transition energy in the halogenated diazaacenes is due to a disproportionate lack of stabilization of the Homo on halogen substitution. The effect results from the unsymmetrical distribution of the Homo, which shows decreased orbital coefficients on the ring bearing chlorine substituents. The more strongly electron-accepting cyano group is predicted to shift the transitions of diazaacenes even further to the red. Electronegative substitution impacts the electronic properties of diazaacenes to a much greater degree than expected.

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Are N,N-Dihydrodiazatetracene Derivatives Antiaromatic?

Cited by 170 publications

References 43 publications

Synthesis of tetraazatetracenes and -pentacenes: role of the substituents for their stability

Synthesis of tetraazatetracenes and -pentacenes: role of the substituents for their stability

The Palladium Way to N‐Heteroacenes

Effects of electronegative substitution on the optical and electronic properties of acenes and diazaacenes

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