Facile Synthesis of Nitrogen‐Doped Nanographenes with Joined Nonhexagons via a Ring Expansion Strategy

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(21)

Published: March 21, 2023

Synthetic methodology is considered a holy grail in both organic chemistry and materials science. Over the past few decades, researchers have explored graphene-type molecules (or nanographenes) through classic Scholl oxidative cyclodehydrogenation. Despite successes achieved with various nanographenes, development of new methods to synthesize these highly desired lags behind. Herein, we developed facile effective method produce series nanographenes bearing nitrogen (N)-doped pentagon-heptagon pairs acceptable yields. Modification heptagonal ring endowed resultant tunable physicochemical properties; for instance, M9 exhibited aggregation-caused quenching aggregation-induced emission behavior. Most strikingly, novel containing N-doped pentagon-octagon were also obtained using same synthetic strategy, demonstrating superior versatility efficiency proposed expansion method.

Language: Английский

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Synthesis of Aza[n]helicenes up to n = 19: Hydrogen-Bond-Assisted Solubility and Benzannulation Strategy

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(25), P. 17428 - 17437

Published: June 12, 2024

Synthetic challenges toward anomalous structures and electronic states often involve handling problems such as insolubility in common organic solvents oxidative degradation under aerobic conditions. We designed benzo-annulated aza[n]helicenes, which benefit from both the suppressed elevation of highest occupied molecular orbital (HOMO) energies high solubility due to hydrogen bonding with solvent molecules overcome these challenges. This strategy enabled synthesis six new aza[n]helicenes ([n]AHs) different lengths (n = 9–19) acyclic precursors via one-pot intramolecular fusion reactions. The all synthesized were determined by X-ray diffraction (XRD) analysis, their electrochemical potentials measured cyclic voltammetry. Among [17]AH [19]AH are first heterohelicenes a triple-layered helix. noncovalent interaction (NCI) plots confirm existence an effective π–π between layers. absorption fluorescence spectra red-shifted helical increased, without any distinct saturation points. optical resolutions N-butylated [9]AH, [11]AH, [13]AH, [15]AH accomplished, circular dichroism (CD) circularly polarized luminescence (CPL) measured. Thus, structural, (chir)optical, properties comprehensively analyzed.

Language: Английский

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Negatively Curved Octagon‐Incorporated Aza‐nanographene and its Assembly with Fullerenes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(15)

Published: Feb. 12, 2024

Abstract A negatively curved aza‐nanographene (NG) containing two octagons was synthesized by a regioselective and stepwise cyclodehydrogenation procedure, in which double aza[7]helicene simultaneously formed as an intermediate. Their saddle‐shaped structures with negative curvature were unambiguously confirmed X‐ray crystallography, thereby enabling the exploration of structure–property relationship photophysical, electrochemical conformational studies. Moreover, assembly octagon‐embedded aza‐NG fullerenes probed fluorescence spectral titration, record‐high binding constants ( K =9.5×10 3 M −1 C 60 , =3.7×10 4 70 ) found among reported polycyclic aromatic compounds. The tight association further elucidated diffraction analysis their co‐crystal, showed formation 1 : complex substantial concave‐convex interactions.

Language: Английский

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Planar, curved and twisted molecular nanographenes: Reduction-induced alkali metal coordination

Coordination Chemistry Reviews, Journal Year: 2023, Volume and Issue: 486, P. 215144 - 215144

Published: April 13, 2023

Language: Английский

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Extension of Non‐alternant Nanographenes Containing Nitrogen‐Doped Stone‐Thrower‐Wales Defects

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(35)

Published: July 8, 2023

Non-alternant topologies have attracted considerable attention due to their unique physiochemical characteristics in recent years. Here, three novel topological nanographenes molecular models of nitrogen-doped Stone-Thrower-Wales (S-T-W) defects were achieved through intramolecular direct arylation. Their chemical structures unambiguously elucidated by single-crystal analysis. Among them, threefold arylation compound (C42 H21 N) is the largest nanographene bearing a N-doped non-alternant topology date, which non-benzenoid rings account for 83 % total skeleton. The absorption maxima this was located near-infrared region with long tail up 900 nm, much longer than those reported similarly sized six-membered (C40 H15 N). In addition, electronic energy gaps these series compounds clearly decreased introduction (from 2.27 eV 1.50 eV). It noteworthy that C42 N possesses such low gap (Egopt =1.40 eV; Egcv =1.50 eV), yet highly stable under ambient conditions. Our work herein demonstrates could significantly influence configurations nanocarbons, where non-alternanting may be an effective way narrow without extending π-conjugation.

Language: Английский

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Highly Contorted Rigid Nitrogen-Rich Nanographene with Four Heptagons

Organic Letters, Journal Year: 2024, Volume and Issue: 26(25), P. 5227 - 5231

Published: March 27, 2024

Nucleophilic substitution of 9,10-dichlorooctafluoroanthracene with 3,4-diethylpyrrole and subsequent Scholl reaction give the annularly fused decapyrrollyl anthracene. Single crystal X-ray analysis revealed a highly contorted geometry induced by combination adjacent heptagons, forming unique 7-7-6-7-7 topology. The end-to-end twist angle along acene moiety is 90°. Cyclic voltammetry studies reveal 6-electron oxidation waves. Density functional theory calculations provided further insights into aromaticity electronic properties this twisted, nitrogen-rich nanographene. structural rigidity high racemization energy barrier have been studied theoretically experimentally VT-NMR.

Language: Английский

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A Negatively Curved Nanographene with Four Embedded Heptagons

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 27, 2024

Negatively curved nanographenes are considered as cutouts of three-dimensional fully sp

Language: Английский

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Facile Functionalization of Ambipolar, Nitrogen-Doped PAHs toward Highly Efficient TADF OLED Emitters

ACS Applied Materials & Interfaces, Journal Year: 2023, Volume and Issue: 15(31), P. 37728 - 37740

Published: July 28, 2023

Despite promising optoelectronic features of N-doped polycyclic aromatic hydrocarbons (PAHs), their use as functional materials remains underdeveloped due to limited post-functionalization. Facing this challenge, a novel design PAHs with D–A–D electronic structure for thermally activated delayed fluorescence (TADF) emitters was performed. Implementing set auxiliary donors at the meta position protruding phenyl ring quinoxaline triggers an increase in charge-transfer property simultaneously decreasing lifetime. This, turn, contributes narrow (0.04–0.28 eV) singlet–triplet exchange energy split (ΔEST) and promotes reverse intersystem crossing transition that is pivotal efficient TADF process. Boosting electron-donating ability our N-PAH scaffold leads excellent photoluminescence quantum yield found solid-state matrix up 96% (for phenoxazine-substituted derivatives, under air) yellow or orange-red emission, depending on specific compound. Organic light-emitting diodes (OLEDs) utilizing six, (D–A)–D, demonstrate significant throughput maximum external efficiency 21.9% which accompanied by remarkable luminance values were all investigated devices range 20,000–30,100 cd/m2 highest reported date OLED domain.

Language: Английский

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Strongly Polarized π-Extended 1,4-Dihydropyrrolo[3,2-b]pyrroles Fused with Tetrazolo[1,5-a]quinolines

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(7), P. 4657 - 4672

Published: March 26, 2024

A straightforward route to 1,4-dihydropyrrolo[3,2-b]pyrroles comprised of two electron-withdrawing quinoline or tetrazolo[1,5-a]quinoline scaffolds has been developed. The versatile multicomponent reaction affording combined with intramolecular direct arylation enables assembly these products in just three steps from anilines overall yields exceeding 30%. planarized, ladder-type heteroacenes possess up 14 conjugated rings. These nominally quadrupolar materials exhibit efficient fluorescence wavelengths spanning most the visible spectrum green–yellow for dyes possessing biaryl bridges and orange–red fully fused systems. In many cases, quantum are large, solvatofluorochromic effects strong, is maintained even crystalline state. Analysis electronic structure molecular architectures using chemical methods suggests that character position flanking heterocycle determine shape HOMO LUMO their extension N-aryl substituents, influencing values molar absorption coefficient. An experimental study two-photon (2PA) properties revealed it occurs 700–800 nm range apparent deviation Laporte parity selection rule, which may be attributed Hertzberg–Teller contribution vibronically allowed 2PA transition.

Language: Английский

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Exploring thermoelectric conduction in new graphene-based molecular junctions dispositive: A computational perspective

Computational and Theoretical Chemistry, Journal Year: 2025, Volume and Issue: unknown, P. 115141 - 115141

Published: Feb. 1, 2025

Language: Английский

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