Nanographenes and Graphene Nanoribbons as Multitalents of Present and Future Materials Science

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(26), С. 11499 - 11524

Опубликована: Июнь 7, 2022

As cut-outs from a graphene sheet, nanographenes (NGs) and nanoribbons (GNRs) are ideal cases with which to connect the world of molecules that bulk carbon materials. While various top-down approaches have been developed produce such nanostructures in high yields, present perspective, precision structural control is emphasized for length, width, edge structures NGs GNRs achieved by modern solution on-surface syntheses. Their possibilities further extended "flatland" three-dimensional world, where chirality handedness jewels crown. In addition properties exhibited at molecular level, self-assembly thin-film cannot be neglected, emphasizes importance processing techniques. With rich toolkit chemistry hand, can endowed versatile functions ranging stimulated emission spintronics bioimaging energy storage, thus demonstrating their multitalents future materials science.

Язык: Английский

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Fluorescent cyclophanes and their applications

Chemical Society Reviews, Год журнала: 2022, Номер 51(13), С. 5557 - 5605

Опубликована: Янв. 1, 2022

In this Review, we feature the recent developments in chemistry of fluorescent cyclophanes, along with their design and synthesis. Their host–guest applications related to structure properties are also highlighted.

Язык: Английский

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Deep‐Blue Narrowband Hetero[6]helicenes Showing Circularly Polarized Thermally Activated Delayed Fluorescence Toward High‐Performance OLEDs

Advanced Materials, Год журнала: 2023, Номер 36(1)

Опубликована: Ноя. 14, 2023

Abstract Helicenes exhibit substantial potential as circularly polarized luminescence (CPL) active molecules. However, their application in organic light‐emitting diodes (CP‐OLEDs) is typically hindered by the challenge of integrating both high color purity and efficient triplet‐harvesting capability, particularly blue spectral region. Herein, a series hetero[6]helicene‐based emitters that strategically engineered through helical extension deep‐blue double‐boron‐based multiple resonance thermally activated delayed fluorescence (MR‐TADF) motif, introduced. Importantly, does not cause apparent structural deformation or perturb frontier molecular orbitals; thus, preserving emission MR‐TADF characteristics parent molecule. This approach also leads to reduced reorganization energy, resulting with narrower linewidth higher photoluminescence quantum yield. Further, motif enhances racemization barrier improved CPL performance dissymmetry factor values up 1.5 × 10 −3 . Exploiting these merits, devices incorporating chiral dopants demonstrate within Broadcast Service Television 2020 color‐gamut range, record external efficiencies (EQEs) 29.3%, have distinctive electroluminescence (CPEL) signals. Overall, authors’ findings underscore promising strategy for designing narrowband chiroptical materials advancing high‐definition displays.

Язык: Английский

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B,N‐Embedded Hetero[9]helicene Toward Highly Efficient Circularly Polarized Electroluminescence

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(18)

Опубликована: Фев. 21, 2024

The intrinsic helical π-conjugated skeleton makes helicenes highly promising for circularly polarized electroluminescence (CPEL). Generally, carbon undergo low external quantum efficiency (EQE), while the incorporation of a multi-resonance thermally activated delayed fluorescence (MR-TADF) BN structure has led to an improvement. However, reported B,N-embedded all show dissymmetry factors (g

Язык: Английский

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Synthesis of π-Conjugated Chiral Organoborane Macrocycles with Blue to Near-Infrared Emissions and the Diradical Character of Cations

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(18), С. 10092 - 10103

Опубликована: Апрель 26, 2023

Highly emissive π-conjugated macrocycles with tunable circularly polarized luminescence (CPL) have sparked theoretical and synthetic interests in recent years. Herein, we report a approach to obtain new chiral organoborane (CMC1, CMC2, CMC3) that are built on the structurally [5]helicenes highly luminescent triarylborane/amine moieties embedded into cyclic systems. These rarely accessible B/N-doped main-group show unique topology dependence of optoelectronic chiroptical properties. CMC1 CMC2 higher dissymmetry factor (glum) together an enhanced CPL brightness (BCPL) as compared CMC3. Electronic effects were also tuned resulted bathochromic shifts their emission responses from blue for near-infrared (NIR) region Furthermore, chemical oxidations N donor sites gave rise stable radical cation (CMC1·+SbF6–) diradical dication species (CMC12·2+2SbF6–) serve rare example positively charged open-shell macrocycle.

Язык: Английский

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π‐Extended Diaza[7]helicenes with Dual Negatively Curved Heptagons: Extensive Synthesis and Spontaneous Resolution into Strippable Homochiral Lamellae with Helical Symmetry

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(11)

Опубликована: Янв. 17, 2024

Abstract We report a unique category of π‐extended diaza[7]helicenes with double negative curvatures. This is achieved by two‐fold regioselective heptagonal cyclization the oligoarylene‐carbazole precursors through either intramolecular C−H arylation or Scholl reaction. The fusion two rings in helical skeleton dramatically increases strain and forces terminal carbazole moieties to stack compressed fashion. presence deformable negatively curved endows resulting dynamic chiral skeletons, aggregation‐induced emission feature relatively low racemization barrier ca. 25.6 kcal mol −1 . Further π‐extension on subsequently leads more sophisticated C 2 ‐symmetric homochiral triple helicene. Notably, these show structure‐dependent stacking upon crystallization, switching from heterochiral packing intra‐layer stacking. Interestingly, helicene molecules spontaneously resolve into lamellar structure 3 1 helix symmetry. Upon ultrasonication nonsolvent, crystals can be readily exfoliated large‐area ultrathin nanosheets height 4.4 nm corresponding layers stacked thicker constituted even‐numbered molecular lamellae. Moreover, regular hexagonal thin platelets size larger than 30 μm fabricated flash aggregation.

Язык: Английский

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Strong Circularly‐Polarized Room‐Temperature Phosphorescence from a Feasibly Separable Scaffold of Bidibenzo[b,d]furan with Locked Axial Chirality

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(30)

Опубликована: Март 30, 2022

Novel accessible scaffold featuring circularly-polarized room-temperature phosphorescence (RTP) is attractive but challenging. Herein, we report a new feasibly separable bidibenzo[b,d]furan compound with strong RTP when doping into the rigid polymer matrix. The simple silica-gel column can separate absolute chiral R-isomer excellent chiroptical properties. experimental data reveal that treated films exhibit an efficiency of 14.8 %, largest dissymmetric factor 0.12, and longest lifetime 0.56 s under ambient conditions. It found reducing nonradiative decays boosts intrinsic emission. impressive results indicate locked axial chirality skeleton endows potential achieving superior emission for small organic optoelectronic molecules.

Язык: Английский

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Circularly Polarized Luminescence in a Möbius Helicene Carbon Nanohoop**

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(37)

Опубликована: Июль 20, 2022

Abstract We present the first helicene carbon nanoohop that integrates a [6]helicene into [7]cycloparaphenylene. The endows nanohoop with chiroptical properties and configurational stability typical for higher helicenes, while radially conjugated seven para ‐phenylenes largely determine optoelectronic properties. structure of was unambiguously characterized by NMR, MS X‐ray analysis revealed it possesses topology Möbius strip in solid state solution. chirality transfers from to leads pronounced circular dichroism bright circularly polarized luminescence, which is affected structural nanohoop.

Язык: Английский

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New advances in chiral nanographene chemistry

Organic Chemistry Frontiers, Год журнала: 2023, Номер 10(16), С. 4167 - 4197

Опубликована: Янв. 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.

Язык: Английский

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A Fused [5]Helicene Dimer with a Figure‐Eight Topology: Synthesis, Chiral Resolution, and Electronic Properties

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(23)

Опубликована: Апрель 3, 2023

Chiral shape-persistent molecular nanocarbons are promising chiroptical materials; their synthesis, however, remains a big challenge. Herein, we report the facile synthesis and chiral resolution of double-stranded figure-eight carbon nanobelt 1 in which two [5]helicene units fused together. Two synthetic routes were developed, and, particular, strategy involving Suzuki coupling-mediated macrocyclization followed by Bi(OTf)3 -catalyzed cyclization vinyl ether turned out to be most efficient. The structure was confirmed X-ray crystallographic analysis. isolated (P,P)- (M,M)- enantiomers show persistent properties with relatively large dissymmetric factors (|gabs |=5.4×10-3 |glum |=1.0×10-2 ), can explained effective electron delocalization along fully conjugated belt unique D2 symmetry. exhibits local aromatic character dominant containing eight Clar's sextet rings.

Язык: Английский

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