Aromaticity and tautomerism of a 4n π electron dihydrohexaazapentacene

Sun, Chun‐Lin; Luo, Xiao-E.; Xu, Hu; Song, Qi‐Wei; Fan, Zhiping; Wang, Xiaozhen; Cao, Jingjing; Shi, Zi‐Fa; Zhang, Hao‐Li

doi:10.1039/c9qo01285k

Cited by 5 publications

(5 citation statements)

References 42 publications

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“…10 and 11 ), in line with the similarity of the electronic properties previously discussed, showing that the five-membered rings, which are aromatic themselves, have negligible effect on the aromatic pattern of the remaining system. Interestingly, for both systems, the cycles containing the nitrogen show sharp antiaromaticity 75 . This further confirms the picture that the nitrogen atoms provide 2 electrons each to the π-system, making the nitrogen-containing cycles have 8 π electrons, which are formally anti-aromatic according to Hückel’s rule.…”

Section: Resultsmentioning

confidence: 97%

On-surface synthesis and characterization of nitrogen-substituted undecacenes

et al. 2022

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Heteroatom substitution in acenes allows tailoring of their remarkable electronic properties, expected to include spin-polarization and magnetism for larger members of the acene family. Here, we present a strategy for the on-surface synthesis of three undecacene analogs substituted with four nitrogen atoms on an Au(111) substrate, by employing specifically designed diethano-bridged precursors. A similarly designed precursor is used to synthesize the pristine undecacene molecule. By comparing experimental features of scanning probe microscopy with ab initio simulations, we demonstrate that the ground state of the synthesized tetraazaundecacene has considerable open-shell character on Au(111). Additionally, we demonstrate that the electronegative nitrogen atoms induce a considerable shift in energy level alignment compared to the pristine undecacene, and that the introduction of hydro-aza groups causes local anti-aromaticity in the synthesized compounds. Our work provides access to the precise fabrication of nitrogen-substituted acenes and their analogs, potential building-blocks of organic electronics and spintronics, and a rich playground to explore π-electron correlation.

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Section: Resultsmentioning

confidence: 97%

On-surface synthesis and characterization of nitrogen-substituted undecacenes

et al. 2022

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“…On the other hand, density functional theory (DFT) calculations at M06L/6-311++G(d,p) level have been carried out on 24 dihydropyrazine annulated linear polyacene systems to study their aromaticity and HOMO-LUMO energy gap [13]. Sun et al, concentrated on the intriguing tautomerism behaviors of a new hexazapentacene derivative, named DHHAP [14]. In solution, DHHAP exists as a mixture of benzenoid and quinonoid tautomers in a rough ratio of 1 : 1.…”

Section: Introductionmentioning

confidence: 99%

“…DFT calculations reveal that DHHAP is slightly more stable than its 4n + 2π hexazapentacene counterpart although it has 4n π electrons. DHHAP exhibits different halochromic behaviors upon addition of strong and mild acids [14].…”

Section: Introductionmentioning

confidence: 99%

Dinitro-[1H,4H]-dihydropyrazines - A DFT treatment

Türker

2024

EJMS

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Dinitro-(1H,4H)-dihydropyrazine isomers and the 1,3- and 1,5-proton tautomers of these isomers are considered within the constraints of density functional theory at the level of B3LYP/6-311++G(d,p). All the structures are electronically stable, thermodynamically exothermic and have favorable Gibbs’ free energy of formation values at the standard states. Various quantum chemical properties, including IR and UV-VIS spectra, the HOMO and LUMO energies etc., have been obtained and discussed. The NICS values have been calculated for the antiaromaticity order of the isomers considered.

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“…Particularly, visible light organic photodetectors can be used in indirect conversion X-ray detectors, fingerprint scanners, and intelligent surfaces of gesture recognition . Moreover, dihydroazapentacenes have interesting features of proton tautomerism and acidochromism that can be manifested for sensing applications …”

Section: Introductionmentioning

confidence: 99%

“…25 Moreover, dihydroazapentacenes have interesting features of proton tautomerism and acidochromism that can be manifested for sensing applications. 26 Herein, we describe the synthesis, characterization, and optoelectronic device applications of a 4nπ stable multitasking N-heteroacene, which showed photoresponsive nature under visible light irradiation, acidochromism in solution, and p-type charge transport in optoelectronic devices.…”

Section: ■ Introductionmentioning

confidence: 99%

4nπ Stable Multitasking Azapentacene: Acidochromism, Hole Mobility, and Visible Light Photoresponse

Das

Mandal

Alam

et al. 2022

ACS Appl. Mater. Interfaces

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Herein, we describe the synthesis, characterization, and optoelectronic investigation of a stable 4nπ dihydrotetraazapentacene derivative. The neutral dihydrotetraazapentacene contains a 24π-conjugated N-heteroacene core with two phenyl pendants appended thereof. The exceptional stability of this formally antiaromatic π-system is attributed to the fused dihydropyrazine ring, which has ethenamine (enamine) conjugations, and hence, the π-electrons delocalize over the nearly planar azapentacene core to endow with a global aromatic characteristic. The embedded dihydropyrazine also offers an additional Clar's sextet with enhanced aromaticity. The present dihydrotetraazapentacene can be considered as a multitasking N-heteroacene, which showed photoresponsive nature under visible light illumination, acidochromism in solution, and p-type charge transport with an appreciable field-effect hole mobility of 0.02 cm 2 V −1 s −1 and a bulk p-type mobility of 0.98 × 10 −4 cm 2 V −1 s −1 in the space charge-limited regime of operation measured in the hole-only device. Nucleus-independent chemical shift calculation, anisotropy of the induced current density plot, and anisotropic mobility calculation were performed to support the experimental findings.

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Aromaticity and tautomerism of a 4n π electron dihydrohexaazapentacene

Abstract: We report herein the intriguing tautomerism behaviors of new dihydrohexaazapentacene derivatives. The dihydrohexaazapentacene molecules with 4n π electrons exist as two stable tautomers in solution and exhibits globe aromaticity.

Cited by 5 publications

References 42 publications

On-surface synthesis and characterization of nitrogen-substituted undecacenes

On-surface synthesis and characterization of nitrogen-substituted undecacenes

Dinitro-[1H,4H]-dihydropyrazines - A DFT treatment

4nπ Stable Multitasking Azapentacene: Acidochromism, Hole Mobility, and Visible Light Photoresponse

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