Effect of Internal Substituents on the Properties of Dibenzo[g,p]chrysene DOI

Yoshihiro Takeo,

Junichiro Hirano,

Norihito Fukui

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(47), P. 8484 - 8488

Published: Nov. 20, 2023

We investigated the chemical and physical properties of internally functionalized dibenzo[g,p]chrysene (DBC) derivatives. These molecules exhibit chiral double-helicene-like structures that are configurationally stable at ambient temperatures. The internal substituents control conformational change in excited state, thereby modulating emission intensity. Notably, DBC derivative with a methylenedioxy unit undergoes aromatization through elimination substituent upon photoexcitation, resulting formation DBC.

Language: Английский

New advances in chiral nanographene chemistry DOI Creative Commons
Hannah V. Anderson, Nicolai D. Gois, Wesley A. Chalifoux

et al.

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(16), P. 4167 - 4197

Published: Jan. 1, 2023

This review will highlight several recent and lesser-reviewed works related to the preparation of chiral nanographenes, specifically focusing on structures prepared by non-Scholl methods.

Language: Английский

Citations

37
π-Extended Helical Multilayer Nanographenes with Layer-Dependent Chiroptical Properties DOI
Wenhui Niu, Yubin Fu, Zhen‐Lin Qiu

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(49), P. 26824 - 26832

Published: Dec. 4, 2023

Helical nanographenes (NGs) have attracted increasing attention recently because of their intrinsic chirality and exotic chiroptical properties. However, the efficient synthesis extended helical NGs featuring a multilayer topology is still underdeveloped, layer-dependent properties remain elusive. In this study, we demonstrate modular synthetic strategy to construct series novel (1-3) with through consecutive Diels-Alder reaction regioselective cyclodehydrogenation from readily accessible phenanthrene-based precursors bearing ethynyl groups. The resultant exhibit bilayer, trilayer, tetralayer structures elongated π extension rigid backbones, as unambiguously confirmed by single-crystal X-ray or electron diffraction analysis. We find that photophysical these are notably influenced degree extension, which varies number layers, leading obvious redshifted absorption, fast rising molar extinction coefficient (ε), markedly boosted fluorescence quantum yield (Φf). Moreover, embedded [7]helicene subunits in result stable chirality, enabling both chiral resolution exploration Profiting good alignment electric magnetic dipole moments determined structure, excellent circular dichroism circularly polarized luminescence response unprecedented high CPL brightness up 168 M-1 cm-1, rendering them promising candidates for emitters.

Language: Английский

Citations

23
Enhancing Chiroptical Responses in Helical Nanographenes via Geometric Engineering of Double [7]Helicenes DOI Creative Commons
Wenhui Niu, Yubin Fu,

Qingsong Deng

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: Feb. 19, 2024

Helical nanographenes with high quantum yields and strong chiroptical responses are pivotal for developing circularly polarized luminescence (CPL) materials. Here, we present the successful synthesis of novel π-extended double [7]helicenes (ED7Hs) where two helicene units fused at meta- or para-position middle benzene ring, respectively, as structural isomers reported ortho-fused ED7H. The geometry these ED7Hs is clearly characterized by single-crystal X-ray analysis. Notably, this class exhibits bright exceeding 40 %. Through geometric regulation embedded [7]helicene from ortho-, to para-position, display exceptional amplification in responses. This enhancement evident a remarkable approximate fivefold increase absorbance dissymmetry factors (g

Language: Английский

Citations

13
Negatively Curved Octagon‐Incorporated Aza‐nanographene and its Assembly with Fullerenes DOI
Jun Liu, Juan Hong,

Zhenxing Liao

et al.

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

Citations

11
A Double Twisted Nanographene with a Contorted Pyrene Core DOI
Yanping Dong, Zhiyu Zhang, Yoshifumi Hashikawa

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(35)

Published: June 21, 2024

The mature synthetic methodologies enable us to rationally design and produce chiral nanographenes (NGs), most of which consist multiple helical motifs. However, inherent chirality originating from twisted geometry has just emerged be employed in NGs. Herein, we report a red-emissive NG constituted orthogonally arranged two-fold π-skeletons at contorted pyrene core contributes optical transitions S

Language: Английский

Citations

11
Direct Edge Functionalization of Corannulene–Coronene Hybrid Nanographenes DOI Creative Commons
Jovana Stanojkovic, Natalia Terenti, Mihaiela C. Stuparu

et al.

JACS Au, Journal Year: 2025, Volume and Issue: unknown

Published: March 24, 2025

For more than a century, electrophilic aromatic substitution reactions have been central to the construction of rich variety organic molecules that are useful in all aspects human life. Typically, small nuclei, such as benzene, provide an ideal substrate. An increase number annulated rings enhances potential reactive sites and frequently results complex product mixtures. Thus, nanographenes with relatively large system seldom selective their positions. Moreover, nanographene substrates scope for multiple patterns remain rare. Herein, we demonstrate curved based on corannulene-coronene hybrid structure comprising 48 conjugated sp 2-carbon atoms allows direct regioselective edge functionalization through bromination, nitration, formylation, Friedel-Crafts acylation good yields. The postsynthetically installed functional groups can be modified versatile chemistry transformations, including (mechanochemical) Suzuki-Miyaura, Sonogashira-Hagihara, Buchwald-Hartwig amination reactions. Furthermore, substitutions carried out sequential manner yield heterofunctional structures. edge-functionalization strategy enables modular access nanostructures appealing properties, strong fluorescence emission visible near-infrared regions (475-900 nm) record Stokes shifts (>300 nm), at exceptionally carbon footprint (C48).

Language: Английский

Citations

1
Helicene‐type β‐isoindigo‐based boron‐dipyrromethene analogs with strong near‐infrared chiroptical activity DOI Creative Commons
Ziwei Chen, Zhigang Ni,

Xing‐Yu Chen

et al.

Aggregate, Journal Year: 2024, Volume and Issue: 5(3)

Published: Jan. 5, 2024

Abstract Near‐infrared (NIR) chiroptical response has been less explored because it is challenging to achieve both chirality and NIR absorption/emission. Herein, we describe the design of heterohelicene‐type β‐isoindigo‐based boron‐dipyrromethene (BODIPY) analogs (β‐IBs), which shift absorption peak 800 nm produce significant Cotton effects (127.8 M −1 cm ) absorbance dissymmetry factors (| g abs | = 3.5 × 10 −3 ). The luminescence factor ( lum circularly polarized (CPL) brightness B CPL up 1.24 1.78 were realized beyond nm. These β‐IBs are first examples helicene‐type compounds with highest in region Theoretical calculations demonstrate that strong activities triggered by their large transition magnetic dipole moments. This study not only provides a new approach synthesis larger variety unprecedented BODIPY but also demonstrates excellent properties.

Language: Английский

Citations

7
Helical Nanographenes Bearing Pentagon‐Heptagon Pairs by Stepwise Dehydrocyclization DOI

Yang‐Yang Ju,

Huan Luo,

Ze‐Jia Li

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(20)

Published: March 6, 2024

The incorporation of pentagon-heptagon pairs into helical nanographenes lacks a facile synthetic route, and the impact these on chiroptical properties remains unclear. In this study, method for stepwise construction in by dehydrogenation [6]helicene units was developed. Three containing were synthesized characterized using approach. A wide variation molecular geometries photophysical observed, with changes length structures introduction pairs. embedded reduced oxidation potential nanographenes. high isomerization energy barriers enabled chiral resolution helicene enantiomers. Chiroptical investigations revealed remarkably enhanced circularly polarized luminescence dissymmetry factors an increasing number

Language: Английский

Citations

7
Helically Chiral π‐Expanded Azocines Through Regioselective Beckmann Rearrangement and Their Charged States DOI Creative Commons

Jan Borstelmann,

Lars Schneider,

Frank Röminger

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(29)

Published: May 8, 2024

Abstract We report a synthetic approach to π‐expanded [6]helicenes incorporating tropone and azocine units in combination with 5‐membered ring, which exhibit intriguing structural, electronic, chiroptical properties. The regioselective Beckmann rearrangement allows the isolation of helical scaffolds containing 8‐membered lactam, azocine, amine units. As shown by X‐ray crystallographic analysis, incorporation or leads highly distorted [6]helicene moieties, distinct packing motifs solid state. compounds promising optoelectronic properties considerable photoluminescence quantum yields tunable emission wavelengths depending on relative position nitrogen center within polycyclic framework. Separation enantiomers chiral high‐performance liquid chromatography (HPLC) allowed characterization their circular dichroism (CD) circularly polarized luminescence (CPL) spectroscopy. feature manifold redox chemistry, allowing for corresponding radical anions cations as well dications dianions, near‐infrared (NIR) absorption bands extending beyond 3000 nm. Detailed theoretical studies provided insights into aromaticity evolution upon reduction oxidation, suggesting that steric strain prevents unit from undergoing aromatization, while indene moiety dominates observed chemistry.

Language: Английский

Citations

7
In Silico Screening and Experimental Verification of Near‐Infrared‐Emissive Two‐Boron‐Doped Polycyclic Aromatic Hydrocarbons DOI Creative Commons

Izumi Hattori,

Masaya Hagai, Masato Ito

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(22)

Published: April 1, 2024

Abstract Embedding two boron atoms into a polycyclic aromatic hydrocarbon (PAH) leads to the formation of neutral analogue that is isoelectronic corresponding dicationic PAH skeleton, which can significantly alter its electronic structure. Based on this concept, we explore herein identification near‐infrared (NIR)‐emissive PAHs with aid an in silico screening method. Using perylene as scaffold, embedded and fused thiophene rings it. design all possible structures (ca. 2500 entities) were generated using comprehensive structure generator. Time‐dependent DFT calculations conducted these structures, promising candidates extracted based vertical excitation energy, transition dipole moment, atomization energy per bond. One dithieno‐diboraperylene was synthesized indeed exhibited emission at 724 nm quantum yield 0.40 toluene, demonstrating validity This modification further applied other PAHs, series thienobora‐modified synthesized.

Language: Английский

Citations

6