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Helikale Nanographene (NG) mit hohen Quantenausbeuten und starken chiroptischen Antworten sind entscheidend für die Entwicklung von lumineszenten Materialien mit zirkularer Polarisation (engl. circular polarized luminescence, CPL). Hier berichten wir von der erfolgreichen Synthese neuartiger π‐erweiterter Doppel‐[7]Helicene (ED7Hs), bei denen sich zwei Helicen‐Einheiten meta bzw. para am zentralen Benzenring befinden. Sie sind damit strukturelle Isomere des bekannten ortho‐ED7H. Die strukturelle Integrität und Geometrie der ED7Hs wurde eindeutig durch Röntgen‐Einkristalldiffraktometrie aufgeklärt. Die ED7Hs besitzen eine ausgeprägte Fluoreszenz mit Quantenausbeuten über 40 %. Durch Variation der relativen Positionen der Doppel‐[7]Helicene am zentralen Benzenring (ortho, meta, para) kann eine außergewöhnliche Verstärkung der chiroptischen Eigenschaften registriert werden. Diese Verbesserung zeigt sich in einem etwa fünffachen Anstieg der Absorbanz und Lumineszenz‐Dissymmetriefaktoren (gabs und glum) sowie einer erhöhten CPL‐Helligkeit von bis zu 176 M−1 cm−1, was die Leistung der meisten helicenbasierten chiralen NGs übertrifft. Des weiteren zeigen DFT‐Simulationen, dass die relative geometrische Lage der [7]Helicene eine präzise Anpassung der elektrischen und magnetischen Übergangsdipolmomente zur Folge hat, welche die beobachteten Verstärkungen der chiroptischen Eigenschaften erklären. Diese Studie liefert eine effektive Strategie zur Verstärkung der CPL‐Eigenschaften chiraler Nanographene, welche ihre Anwendbarkeit als CPL‐Emitter verbessert. [ABSTRACT FROM AUTHOR]

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 are fused at the meta‐ or para‐position of the middle benzene ring, respectively, as the structural isomers of the reported ortho‐fused ED7H. The structural geometry of these ED7Hs is clearly characterized by single‐crystal X‐ray analysis. Notably, this class of ED7Hs exhibits bright luminescence with high quantum yields exceeding 40 %. Through geometric regulation of two embedded [7]helicene units from ortho‐, meta‐ to para‐position, these ED7Hs display exceptional amplification in chiroptical responses. This enhancement is evident in a remarkable approximate fivefold increase in the absorbance and luminescence dissymmetry factors (gabs and glum), respectively, along with a boosted CPL brightness up to 176 M−1 cm−1, surpassing the performance of most helicene‐based chiral NGs. Furthermore, DFT calculations elucidate that the geometric adjustment of two [7]helicene units allows the precise alignment of electric and magnetic transition dipole moments, leading to the observed enhancement of their chiroptical responses. This study offers an effective strategy for magnifying the CPL performance in chiral NGs, promoting their expanded application as CPL emitters. [ABSTRACT FROM AUTHOR]

Binding water molecules to polar sites in covalent organic frameworks (COFs) is inevitable, but the corresponding solvent effects in electrocatalytic process have been largely overlooked. Herein, we investigate the solvent effects on COFs for catalyzing the oxygen reduction reaction (ORR). Our designed COFs incorporated different kinds of nitrogen atoms (imine N, pyridine N, and phenazine N), enabling tunable interactions with water molecules. These interactions play a crucial role in modulating electronic states and altering the catalytic centers within the COFs. Among the synthesized COFs, the one with pyridine N atoms exhibits the highest activity, with characterized by a half‐wave potential of 0.78 V and a mass activity of 0.32 A mg−1, which surpass those from other metal‐free COFs. Theoretical calculations further reveal that the enhanced activity can be attributed to the stronger binding ability of *OOH intermediates to the carbon atoms adjacent to the pyridine N sites. This work sheds light on the significance of considering solvent effects on COFs in electrocatalytic systems, providing valuable insights into their design and optimization for improved performance. [ABSTRACT FROM AUTHOR]

Binding water molecules to polar sites in covalent organic frameworks (COFs) is inevitable, but the corresponding solvent effects in electrocatalytic process have been largely overlooked. Herein, we investigate the solvent effects on COFs for catalyzing the oxygen reduction reaction (ORR). Our designed COFs incorporated different kinds of nitrogen atoms (imine N, pyridine N, and phenazine N), enabling tunable interactions with water molecules. These interactions play a crucial role in modulating electronic states and altering the catalytic centers within the COFs. Among the synthesized COFs, the one with pyridine N atoms exhibits the highest activity, with characterized by a half‐wave potential of 0.78 V and a mass activity of 0.32 A mg−1, which surpass those from other metal‐free COFs. Theoretical calculations further reveal that the enhanced activity can be attributed to the stronger binding ability of *OOH intermediates to the carbon atoms adjacent to the pyridine N sites. This work sheds light on the significance of considering solvent effects on COFs in electrocatalytic systems, providing valuable insights into their design and optimization for improved performance. [ABSTRACT FROM AUTHOR]

Die Inkorporation von Nanoporen in Graphen‐Nanostrukturen wurde als effiziente Methode zur Anpassung der Bandlücke und elektronischen Struktur dieser Materialien demonstriert. Allerdings ist die atomgenaue Einbettung uniformer Nanoporen in Graphen‐Nanostreifen (GNS, engl. GNR) auf atomarer Ebene durch Mangel an effizienten Synthesestrategien bislang unterentwickelt. Wir berichten hier vom ersten lösungschemisch dargestellten, vollständig durch Scholl‐Reaktion konjugierten porösen GNS (pGNS), welchen wir durch das atomgenau dargestellte Polyphenylen P1 mit vorinstallierten hexagonalen Makrozyklen zugänglich machen konnten. pGNS enthält periodische Poren im sub‐Nanometerbereich (0.6 nm) mit einem Abstand von 1.7 nm zueinander. Um unsere Synthesestrategie zu untermauern, wurden zwei poröse Modellverbindungen (1 a, 1 b) mit einer zu pGNS identischen Pore erfolgreich dargestellt. Die chemische Struktur und photophysikalischen Eigenschaften von pGNS wurden durch verschiedene spektroskopische Methoden untersucht. Die eingebetteten periodischen Nanoporen vermindern die π‐Konjugation und damit die Interaktion zwischen den Nanostreifen, verglichen mit nicht porösen GNS von ähnlicher Breite. pGNS zeigt demzufolge eine erhöhte Bandlücke und eine verbesserte nasschemische Prozessierbarkeit. [ABSTRACT FROM AUTHOR]

The incorporation of nanopores into graphene nanostructures has been demonstrated as an efficient tool in tuning their band gaps and electronic structures. However, precisely embedding the uniform nanopores into graphene nanoribbons (GNRs) at the atomic level remains underdeveloped especially for in‐solution synthesis due to the lack of efficient synthetic strategies. Herein we report the first case of solution‐synthesized porous GNR (pGNR) with a fully conjugated backbone via the efficient Scholl reaction of tailor‐made polyphenylene precursor (P1) bearing pre‐installed hexagonal nanopores. The resultant pGNR features periodic subnanometer pores with a uniform diameter of 0.6 nm and an adjacent‐pores‐distance of 1.7 nm. To solidify our design strategy, two porous model compounds (1 a, 1 b) containing the same pore size as the shortcuts of pGNR, are successfully synthesized. The chemical structure and photophysical properties of pGNR are investigated by various spectroscopic analyses. Notably, the embedded periodic nanopores largely reduce the π‐conjugation degree and alleviate the inter‐ribbon π–π interactions, compared to the nonporous GNRs with similar widths, affording pGNR with a notably enlarged band gap and enhanced liquid‐phase processability. [ABSTRACT FROM AUTHOR]

Das Forschungsinteresse an in polyzyklische aromatische Kohlenwasserstoffe (PAKs) eingebettete Azulene hat sich in den letzten Jahren signifikant erhöht, aber der Mangel an effizienten Synthesestrategien hemmt die Studien der Struktur‐Eigenschaftsbeziehungen sowie weiterer opto‐elektronischer Anwendungen. Wir berichten hier von einer neuen modularen Synthesestrategie für diverse Azulen‐eingebettete PAKs durch eine Tandem Suzuki Kupplung und basenvermittelte Kondensation des knoevenagel Typs in guten Ausbeuten und exzellenter struktureller Vielfalt. Die Substrate beinhalten nicht‐alternierende thiophenreiche PAKs, schmetterlings‐ und z‐förmige PAKs mit zwei Azuleneinheiten sowie das erste Beispiel zweier eingebetteter Azuleneinheiten, welche ein doppel‐[5]Helicen bilden. Die strukturelle Topologie, Aromatizität und die photophysischen Eigenschaften wurden per NMR Spektroskopie, Einkristallstrukturanalyse, UV/Vis Absorptionsspektroskopie sowie durch DFT Simulationen untersucht. Diese Strategie stellt eine neue Herangehensweise für die zügige Synthese bisher nicht erforschter, nicht‐alternierender PAKs oder Graphennanostreifen mit mehreren Azuleneinheiten dar. [ABSTRACT FROM AUTHOR]

The research interest in azulene‐embedded polycyclic aromatic hydrocarbons (PAHs) has significantly increased recently, but the lack of efficient synthetic strategies impedes the investigation of their structure‐property relationships and further opto‐electronic applications. Here we report a modular synthetic strategy towards diverse azulene‐embedded PAHs by a tandem Suzuki coupling and base‐promoted Knoevenagel‐type condensation with good yields and great structural versatility, including non‐alternant thiophene‐rich PAHs, butterfly‐ or Z‐shaped PAHs bearing two azulene units, and the first example of a two‐azulene‐embedded double [5]helicene. The structural topology, aromaticity and photophysical properties were investigated by NMR, X‐ray crystallography analysis and UV/Vis absorption spectroscopy assisted by DFT calculations. This strategy provides a new platform for rapidly synthesizing unexplored non‐alternant PAHs or even graphene nanoribbons with multiple azulene units. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are attractive as metal-free catalysts for the 2e− oxygen reduction reaction (ORR) towing to their tunable skeletons and porosities. However, the specific roles of their properties, such as crystallinity, porosity, dipole moment, and binding ability to reactants, in the catalytic performance are still unknown. In this work, we adopted a linker engineering strategy to reveal the crucial factors in determining the catalytic performance. The properties of the COFs were systematically engineered by altering the substituent groups in the linkers. The optimized Br-COF achieved a maximum selectivity of 86.2%, and a mass activity of 32.0 A g−1, which were 112% and 174% higher than those from unmodified COF, respectively. The experimental and theoretical results revealed that the reductive ability of the COFs exerted the most prominent effect on their catalytic activity and confirmed that the easy formation of an OOH* intermediate contributed to the high activity. [Display omitted] • We have developed seven catalytic COFs with the same topology and porosities, binding ability of O 2 , but possess reductive ability, and thus contributed tailored catalytic activity and selectivity (Br-> Cl-> OH-> OCH 3 -> F-> CH 3 -> H-COF). • The optimized Br-COF exhibited the highest activity and selectivity in the 2e− ORR, which were higher than other reported COFs. • The experimental and theoretical results revealed that the COF with strong reducing ability is easy to form OOH* intermediates, which makes its activity high. [ABSTRACT FROM AUTHOR]

[Display omitted] • The 1D COFs with alkynal units were constructed for improving OER activity. • The electronic conductivity and charge transfer ability can be modulated in 1D COFs. • The weaker stacking interaction between chains allowed expansion of the interlayer. • The DFT calculation revealed alkynal unites promoted OOH* desorption on Fe sites. Covalent organic frameworks (COFs) have been employed to catalyze the oxygen evolution reaction (OER). However, their catalytic activities have been limited, because their narrow interlayer space hindered the mass transport to the catalytic sites. Herein, we have demonstrated dimensional-controlled interlayer space of COFs for OER. The one dimensional (1D) catalytic COF had weaker stacking interaction between the 1D chains than that from two-dimensional COFs, which allowed for easier expansion of the interlayer distance in catalytic process, leading to enhanced catalytic activity. Moreover, the electronic states were well modulated with extending the length of conjugating units by integrating the alkynal units. The optimized catalyst achieved an overpotential of 225 mV and Tafel slope of 76 mV dec–1 in 1.0 M KOH, outperforming other 2D or 3D COFs. Theoretical calculations demonstrated that the alkynal units facilitated the OOH* desorption on the Fe sites, which further improved the activity. [ABSTRACT FROM AUTHOR]

Combining solution‐based and surface‐assisted synthesis, we demonstrate the first synthesis of NBN‐doped bis‐tetracene (NBN‐BT) and peri‐tetracene (NBN‐PT). The chemical structures are clearly elucidated by high‐resolution scanning tunneling microscopy (STM) in combination with noncontact atomic force microscopy (nc‐AFM). Scanning tunneling spectroscopy (STS) characterizations reveal that NBN‐BT and NBN‐PT possess higher energy gaps than bis‐tetracene and peri‐tetracene. Interestingly, NBN‐BT can undergo stepwise one‐electron oxidation and convert into its corresponding radical cation and then to its dication. The energy gap of the NBN‐BT dication is similar to that of bis‐tetracene, indicating their isoelectronic relationship. Moreover, a similar energy gap between the NBN‐PT dication and peri‐tetracene can be predicted by DFT calculations. This work provides a novel synthesis along with characterizations of multi‐NBN‐doped zigzag‐edged peri‐acenes with tunable electronic properties. [ABSTRACT FROM AUTHOR]

Combining solution‐based and surface‐assisted synthesis, we demonstrate the first synthesis of NBN‐doped bis‐tetracene (NBN‐BT) and peri‐tetracene (NBN‐PT). The chemical structures are clearly elucidated by high‐resolution scanning tunneling microscopy (STM) in combination with noncontact atomic force microscopy (nc‐AFM). Scanning tunneling spectroscopy (STS) characterizations reveal that NBN‐BT and NBN‐PT possess higher energy gaps than bis‐tetracene and peri‐tetracene. Interestingly, NBN‐BT can undergo stepwise one‐electron oxidation and convert into its corresponding radical cation and then to its dication. The energy gap of the NBN‐BT dication is similar to that of bis‐tetracene, indicating their isoelectronic relationship. Moreover, a similar energy gap between the NBN‐PT dication and peri‐tetracene can be predicted by DFT calculations. This work provides a novel synthesis along with characterizations of multi‐NBN‐doped zigzag‐edged peri‐acenes with tunable electronic properties. [ABSTRACT FROM AUTHOR]

An aqueous emulsion polymerization self‐assembly approach is demonstrated for the first time to synthesize ultrahigh nitrogen containing mesoporous polymer nanospheres, using melamine‐formaldehyde resin oligomers as precursors. In the synthesis, change from alkaline to acidic conditions is critical for the formation of monodisperse mesostructured polymer nanospheres. Owing to unique structure of triazine stabilized in the covalent polymeric networks during the pyrolysis process, the derived mesoporous carbon nanospheres possess an ultrahigh nitrogen content (up to 15.6 wt%) even after pyrolysis at 800 °C, which is the highest nitrogen content among mesoporous carbon nanospheres. Furthermore, these monodisperse mesoporous carbon nanospheres possess a high surface area (≈883 m2 g−1) and large pore size (≈8.1 nm). As an anode for sodium‐ion batteries, the ultrahigh nitrogen‐containing mesoporous carbon nanospheres exhibit superior rate capability (117 mAh g−1 at a high current density of 3 A g−1) and high reversible capacity (373 mAh g−1 at 0.06 A g−1), indicating a promising material for energy storage. [ABSTRACT FROM AUTHOR]

Nanographenes (NGs) with tunable electronic and magnetic properties have attracted enormous attention in the realm of carbon‐based nanoelectronics. In particular, NGs with biradical character at the ground state are promising building units for molecular spintronics. However, most of the biradicaloids are susceptible to oxidation under ambient conditions and photolytic degradation, which hamper their further applications. Herein, we demonstrated the feasibility of tuning the magnetic properties of zigzag‐edged NGs in order to enhance their stability via the controlled Diels–Alder reactions of peri‐tetracene (4‐PA). The unstable 4‐PA (y0=0.72; half‐life, t1/2=3 h) was transformed into the unprecedented benzo‐peri‐tetracenes (BPTs) by a one‐side Diels–Alder reaction, which featured a biradical character at the ground state (y0=0.60) and exhibited remarkable stability under ambient conditions for several months. In addition, the fully zigzag‐edged circumanthracenes (CAs) were achieved by two‐fold or stepwise Diels–Alder reactions of 4‐PA, in which the magnetic properties could be controlled by employing the corresponding dienophiles. Our work reported herein opens avenues for the synthesis of novel zigzag‐edged NGs with tailor‐made magnetic properties. [ABSTRACT FROM AUTHOR]

We report the first bottom‐up synthesis of NBN‐doped zigzag‐edged GNRs (NBN‐ZGNR1 and NBN‐ZGNR2) through surface‐assisted polymerization and cyclodehydrogenation based on two U‐shaped molecular precursors with an NBN unit preinstalled at the zigzag edge. The resultant zigzag‐edge topologies of GNRs are elucidated by high‐resolution scanning tunneling microscopy (STM) in combination with noncontact atomic force microscopy (nc‐AFM). Scanning tunneling spectroscopy (STS) measurements and density functional theory (DFT) calculations reveal that the electronic structures of NBN‐ZGNR1 and NBN‐ZGNR2 are significantly different from those of their corresponding pristine fully‐carbon‐based ZGNRs. Additionally, DFT calculations predict that the electronic structures of NBN‐ZGNRs can be further tailored to be gapless and metallic through one‐electron oxidation of each NBN unit into the corresponding radical cations. This work reported herein provides a feasible strategy for the synthesis of GNRs with stable zigzag edges yet tunable electronic properties. [ABSTRACT FROM AUTHOR]

We report the first bottom‐up synthesis of NBN‐doped zigzag‐edged GNRs (NBN‐ZGNR1 and NBN‐ZGNR2) through surface‐assisted polymerization and cyclodehydrogenation based on two U‐shaped molecular precursors with an NBN unit preinstalled at the zigzag edge. The resultant zigzag‐edge topologies of GNRs are elucidated by high‐resolution scanning tunneling microscopy (STM) in combination with noncontact atomic force microscopy (nc‐AFM). Scanning tunneling spectroscopy (STS) measurements and density functional theory (DFT) calculations reveal that the electronic structures of NBN‐ZGNR1 and NBN‐ZGNR2 are significantly different from those of their corresponding pristine fully‐carbon‐based ZGNRs. Additionally, DFT calculations predict that the electronic structures of NBN‐ZGNRs can be further tailored to be gapless and metallic through one‐electron oxidation of each NBN unit into the corresponding radical cations. This work reported herein provides a feasible strategy for the synthesis of GNRs with stable zigzag edges yet tunable electronic properties. [ABSTRACT FROM AUTHOR]

Three unprecedented helical nanographenes (1, 2, and 3) containing an azulene unit are synthesized. The resultant helical structures are unambiguously confirmed by X‐ray crystallographic analysis. The embedded azulene unit in 2 possesses a record‐high twisting degree (16.1°) as a result of the contiguous steric repulsion at the helical inner rim. Structural analysis in combination with theoretical calculations reveals that these helical nanographenes manifest a global aromatic structure, while the inner azulene unit exhibits weak antiaromatic character. Furthermore, UV/Vis‐spectral measurements reveal that superhelicenes 2 and 3 possess narrow energy gaps (2: 1.88 eV; 3: 2.03 eV), as corroborated by cyclic voltammetry and supported by density functional theory (DFT) calculations. The stable oxidized and reduced states of 2 and 3 are characterized by in‐situ EPR/Vis–NIR spectroelectrochemistry. Our study provides a novel synthetic strategy for helical nanographenes containing azulene units as well as their associated structures and physical properties. [ABSTRACT FROM AUTHOR]

Three unprecedented helical nanographenes (1, 2, and 3) containing an azulene unit are synthesized. The resultant helical structures are unambiguously confirmed by X‐ray crystallographic analysis. The embedded azulene unit in 2 possesses a record‐high twisting degree (16.1°) as a result of the contiguous steric repulsion at the helical inner rim. Structural analysis in combination with theoretical calculations reveals that these helical nanographenes manifest a global aromatic structure, while the inner azulene unit exhibits weak antiaromatic character. Furthermore, UV/Vis‐spectral measurements reveal that superhelicenes 2 and 3 possess narrow energy gaps (2: 1.88 eV; 3: 2.03 eV), as corroborated by cyclic voltammetry and supported by density functional theory (DFT) calculations. The stable oxidized and reduced states of 2 and 3 are characterized by in‐situ EPR/Vis–NIR spectroelectrochemistry. Our study provides a novel synthetic strategy for helical nanographenes containing azulene units as well as their associated structures and physical properties. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted considerable attention as adsorbents for capturing and separating gold from electronic wastes. To enhance the binding capture efficiency, constructing hydrogen‐bond nanotraps along the pore walls was one of the most widely adopted approaches. However, the development of absorbing skeletons was ignored due to the weak binding ability of the gold salts (Au). Herein, we demonstrated skeleton engineering to construct highly efficiently absorbs for Au capture. The strong electronic donating feature of diarylamine units enhanced the electronic density of binding sites (imine‐linkage) and thus resulted in high capacities over 1750 mg g−1 for all three COFs. Moreover, the absorbing performance was further improved via the ionization of diarylamine units. The ionic COF achieved 90 % of the maximal adsorption capacity, 1.63 times of that from the charge‐neutral COF within ten minutes, and showed remarkable uptakes of 1834 mg g−1, exceptional selectivity (97.45 %) and cycling stability. The theoretical calculation revealed the binding sites altering from imine bonds to ionic amine sites after ionization of the frameworks, which enabled to bind the AuCl4− via coulomb force and contributed to enhanced absorbing kinetics. This work inspires us to design molecular/ionic capture based on COFs. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted considerable attention as adsorbents for capturing and separating gold from electronic wastes. To enhance the binding capture efficiency, constructing hydrogen‐bond nanotraps along the pore walls was one of the most widely adopted approaches. However, the development of absorbing skeletons was ignored due to the weak binding ability of the gold salts (Au). Herein, we demonstrated skeleton engineering to construct highly efficiently absorbs for Au capture. The strong electronic donating feature of diarylamine units enhanced the electronic density of binding sites (imine‐linkage) and thus resulted in high capacities over 1750 mg g−1 for all three COFs. Moreover, the absorbing performance was further improved via the ionization of diarylamine units. The ionic COF achieved 90 % of the maximal adsorption capacity, 1.63 times of that from the charge‐neutral COF within ten minutes, and showed remarkable uptakes of 1834 mg g−1, exceptional selectivity (97.45 %) and cycling stability. The theoretical calculation revealed the binding sites altering from imine bonds to ionic amine sites after ionization of the frameworks, which enabled to bind the AuCl4− via coulomb force and contributed to enhanced absorbing kinetics. This work inspires us to design molecular/ionic capture based on COFs. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic azomethine ylides (PAMYs) are versatile building blocks for the bottom‐up construction of unprecedented nitrogen‐containing polycyclic aromatic hydrocarbons (N‐PAHs). Here, we demonstrate the 1,3‐dipolar cycloaddition between PAMY and 1,4‐diphenylbut‐2‐yne‐1,4‐dione and the subsequent condensation reaction with hydrazine, which led to unique N‐PAHs with a phenyl‐substituted pyrrolopyridazine core (PP‐1 and PP‐2). The molecular structures of pristine PP‐1 and tert‐butyl‐substituted PP‐2 were verified by NMR spectroscopy and mass spectrometry. Moreover, the structure of PP‐2 was unambiguously elucidated by X‐ray single crystal analysis. The optoelectronic properties were investigated by solvent‐dependent UV‐Vis absorption and fluorescence emission spectroscopy as well as cyclic voltammetry. Additionally, density functional theory (DFT) calculations showed that PP‐1 and PP‐2 exhibit push–pull behavior. Furthermore, in situ EPR/UV‐Vis‐NIR spectroelectrochemistry allowed the detailed insight into the spectroscopic properties and spin distribution of radical cation species of PP‐2. [ABSTRACT FROM AUTHOR]

Abstract The best strategy to improve the solubility of two-dimensional materials is merge them into a polymer backbone or a polymer matrix to form new kind of functional materials. A novel π-conjugated and highly soluble organophosphorus-based polymer covalently functionalized reduced graphene oxide derivative material, PTPEB- g -RGO, has been successfully synthesized, characterized, and was used as active layer material in resistive random access memory (RRAM) devices. The as-fabricated Al/PTPEB- g -RGO/ITO device exhibited nonvolatile bistable resistive switching performances with a large ON/OFF current ratio surpassing 104, long retention time over 104 s, excellent endurance over 200 switching cycles, significant slight |ΔON-OFF| value and remarkable repeated "write-read-erase-read-rewrite" capability. A slight value difference between the turn on voltage and turn off voltage is beneficial for reducing power consumption and decreasing information misreading rate in digital memory cell. The present research work offers a significant insight for the future development of organic memory devices by taking advantage of organophosphorus-based polymer material. Graphical abstract Image [ABSTRACT FROM AUTHOR]

Summary: A novel anode modified by 1,5‐dihydroxyanthraquinone/multiwalled carbon nanotubes (DAQ/MWCNTs) composite was fabricated in order to improve its electrochemical performance in marine sediment microbial fuel cell (MSMFC). The number of microbes on the DAQ/MWCNTs modified anode is 18.02 times of blank anode, and it has the best electrochemical performance compared with other anodes. Its exchange current density and biofilm capacitance are 1472.15 times and 18.66 times higher than that of blank anode, respectively. The maximum power density of composite modified MSMFC (890.12 mW·m−2) is 3.01‐fold of blank cell (296.11 mW·m−2). The mechanism analysis of DAQ/MWCNTs shows that DAQ, as an electron‐transfer mediator, can accelerate electron transfer to benefit the electrochemical performance of anode. This provides a new anode modification method for the development of high power MSMFC as long‐term power source to drive monitoring instruments. [ABSTRACT FROM AUTHOR]

Herein, we report the design and synthesis of a series of novel cationic nitrogen-doped nanographenes (CNDNs) with nonplanar geometry and axial chirality. Single-crystal X-ray analysis reveals helical and cove-edged structures. Compared to their all-carbon analogues, the frontier orbitals of the CNDNs are energetically lower lying, with a reduced optical energy gap and greater electron-accepting behavior. Cyclic voltammetry shows all the derivatives to undergo quasireversible reductions. In situ spectroelectrochemical studies prove that, depending on the number of nitrogen dopants, either neutral radicals (one nitrogen dopant) or radical cations (two nitrogen dopants) are formed upon reduction. The concept of cationic nitrogen doping and introducing helicity into nanographenes paves the way for the design and synthesis of expanded nanographenes or even graphene nanoribbons with cationic nitrogen dopants. [ABSTRACT FROM AUTHOR]

Wir berichten über Design und Synthese einer Serie von neuen kationischen stickstoffdotierten Nanographenen (CNDN) mit einer nichtplanaren Geometrie und axialer Chiralität. Einkristall‐Röntgendiffraktometrie beweist deren helikale und teils “Cove”‐terminierte Struktur. Verglichen mit den reinen Kohlenstoffanalogen liegen die Grenzorbitale der CNDN energetisch tiefer, was zu einer verringerten optischen Energielücke und einer erhöhten Elektronenaffinität führt. Alle Derivate zeigen in cyclovoltammetrischen Untersuchungen quasireversibles Reduktionsverhalten. Abhängig von der Zahl an Stickstoffdotanden ist es möglich, neutrale Radikale (bei einem Stickstoffdotanden) oder Radikalkationen (bei zwei Stickstoffdotanden) während des Reduktionsprozesses über In‐situ‐Spektroelektrochemie zu analysieren. Kationische Stickstoffdotierung kombiniert mit Helizität erschließt neue Wege für das Design und die Synthese von ausgedehnten Nanographenen und Nanographenstreifen. Stickstoff Plus: Ein „Bottom‐up”‐Ansatz ermöglicht einen einfachen Zugang zu kationischen stickstoffdotierten helikalen Nanographenen. Die neuen Nanographene haben vielversprechende Eigenschaften für optische und elektronische Anwendungen. [ABSTRACT FROM AUTHOR]

A new dual-boron-cored luminogen ligated with a nitrogen-containing multidentate ligand and four bulky phenyl rings was readily synthesized. The unique molecular structure endows this BN-containing luminogen with rich photophysical properties in either solution or in the solid state, including a large Stokes shift, aggregation induced emission activity and reversible piezochromism. Furthermore, this BN-containing luminogen exhibits good capabilities for imaging living cells and sensing of fluoride anions. [ABSTRACT FROM AUTHOR]

Improving anode performance is of great significance to scale up benthic microbial fuel cells (BMFCs) for its marine application to drive oceanography instruments. In this study, manganese oxide (MnO 2 )/multiwall carbon nanotubes (MWCNTs) composites are prepared to be as novel anodes in the BMFCs via a direct redox reaction between permanganate ions (MnO 4 − ) and MWCNTs. The results indicate that the MnO 2 /MWCNTs anode has a better wettability, greater kinetic activity and higher power density than that of the plain graphite (PG) anode. It is noted that the MnO 2 (50% weight percent)/MWCNTs anode shows the highest electrochemical performance among them and will be a promising material for improving bioelectricity production of the BMFCs. Finally, a synergistic mechanism of electron transfer shuttle of Mn ions and their redox reactions in the interface between modified anode and bacteria biofilm are proposed to explain its excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel Fe/ferric oxide modified anode has been fabricated and utilized to construct marine sediment microbial fuel cell and it has achieved higher voltage (1.0∼1.1V) and power output than that of its plain cell. [•] A novel composite mechanism of both chemical and microbial enhancement is also presented. [Copyright &y& Elsevier]

Abstract: Tubular halloysite can be used as a template to fabricate a novel metallized ceramic microstructure through electroless plating. Reduction of Pd ions by methanol is conducted to initiate Ni plating. There is a simultaneous deposition of Ni nanoparticles on the outer surface and discontinuous wires in the lumen site of the halloysite template obtained. The different deposition could be caused by the different composition distribution of ferric oxide impurity in the wall due to the isomorphic substitution during the formation of halloysite template. Its magnetic property is mainly attributed to the Ni nanoparticles, not the wires. The metallized ceramic microstructure has the potential to be utilized as a novel magnetic material. [Copyright &y& Elsevier]

[Display omitted] • The ladder covalent organic frameworks showed high electrocatalytic performance. • The ladder π-conjugation contributed to electronic conductivity. • The natural phenolic molecule improved CO 2 uptakes and reductive capacity. • The theoretical calculation revealed the phenolic molecule enhance the activity. Covalent organic frameworks (COFs) constructed with metallocyclophane units and organic linkers have found application as electrocatalytic systems. Nevertheless, the majority of linkers within COFs necessitate intricate design and synthesis. Conversely, the potential utilization of natural building blocks in COF construction remains largely unexplored. In this study, we constructed a natural COF (CoPc-EA-COF) by employing a natural phenolic molecule (ellagic acid (EA)) as the linker and Co-hexadecafluorophthalocyanine (CoPc) as blocks. This framework serves as an electrocatalyst for both the oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO 2 RR). The incorporation of EA units imparts the CoPc-EA-COF with elevated electronic conductivity, enhanced CO 2 binding affinity, and superior reductive capacity compared to the controlled COF lacking EA units. The CoPc-EA-COF demonstrated enhanced performance in the ORR, as evidenced by a half-wave potential of 0.80 V. Moreover, it showcased elevated activity and selectivity in the CO 2 RR, achieving a maximum CO faradic efficiency of 97.32 % at − 0.8 V, along with turnover frequency (TOF) values reaching 2092 h−1. Theoretical calculations revealed that the presence of EA units facilitated the generation of OOH* and COOH* species, which are pivotal in the rate-determining stages of both ORR and CO 2 RR processes. The contribution of EA units significantly bolstered the overall catalytic activity. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a novel one‐pot synthetic method towards a series of boron‐doped polycyclic aromatic hydrocarbons (B‐PAHs, 1 a–1 o), including hitherto unknown B‐doped zethrene derivatives, from ortho‐aryl substituted diarylalkynes with high atom efficiency and broad substrate scopes. A reaction mechanism is proposed based on the experimental investigation together with the theoretical calculations, which involves a unique 1,4‐boron migration process. The resultant benchtop‐stable B‐PAHs are thoroughly investigated by X‐ray crystallography, cyclic voltammetry, UV/Vis absorption, and fluorescence spectroscopies. The blue and green organic light‐emitting diode (OLED) devices based on 1 f and 1 k are further fabricated, demonstrating the promising application potential of B‐PAHs in organic optoelectronics. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a novel one‐pot synthetic method towards a series of boron‐doped polycyclic aromatic hydrocarbons (B‐PAHs, 1 a–1 o), including hitherto unknown B‐doped zethrene derivatives, from ortho‐aryl substituted diarylalkynes with high atom efficiency and broad substrate scopes. A reaction mechanism is proposed based on the experimental investigation together with the theoretical calculations, which involves a unique 1,4‐boron migration process. The resultant benchtop‐stable B‐PAHs are thoroughly investigated by X‐ray crystallography, cyclic voltammetry, UV/Vis absorption, and fluorescence spectroscopies. The blue and green organic light‐emitting diode (OLED) devices based on 1 f and 1 k are further fabricated, demonstrating the promising application potential of B‐PAHs in organic optoelectronics. [ABSTRACT FROM AUTHOR]

Heteroatom‐doped peri‐acenes (PAs) have recently attracted considerable attention considering their fascinating physical properties and chemical stability. However, the precise sole addition of boron atoms along the zigzag edges of PAs remains challenging, primarily due to the limited synthetic approach. Herein, we present a novel one‐pot modular synthetic strategy toward unprecedented boron‐doped PAs (B‐PAs), including B‐[4,2]PA (1 a‐2), B‐[4,3]PA (1 b‐2) and B‐[7,2]PA (1 c‐3) derivatives, through efficient intramolecular electrophilic borylation. Their chemical structures are unequivocally confirmed with a combination of mass spectrometry, NMR, and single‐crystal X‐ray diffraction analysis. Notably, 1 b‐2 exhibits an almost planar geometry, whereas 1 a‐2 displays a distinctive bowl‐like distortion. Furthermore, the optoelectronic properties of this series of B‐PAs are thoroughly investigated by UV/Vis absorption and fluorescence spectroscopy combined with DFT calculation. Compared with their parent all‐carbon analogs, the obtained B‐PAs exhibit high stability, wide energy gaps, and high photoluminescence quantum yields of up to 84 %. This study reveals the exceptional ability of boron doping to finely tune the physicochemical properties of PAs, showcasing their potential applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Heteroatom‐doped peri‐acenes (PAs) have recently attracted considerable attention considering their fascinating physical properties and chemical stability. However, the precise sole addition of boron atoms along the zigzag edges of PAs remains challenging, primarily due to the limited synthetic approach. Herein, we present a novel one‐pot modular synthetic strategy toward unprecedented boron‐doped PAs (B‐PAs), including B‐[4,2]PA (1 a‐2), B‐[4,3]PA (1 b‐2) and B‐[7,2]PA (1 c‐3) derivatives, through efficient intramolecular electrophilic borylation. Their chemical structures are unequivocally confirmed with a combination of mass spectrometry, NMR, and single‐crystal X‐ray diffraction analysis. Notably, 1 b‐2 exhibits an almost planar geometry, whereas 1 a‐2 displays a distinctive bowl‐like distortion. Furthermore, the optoelectronic properties of this series of B‐PAs are thoroughly investigated by UV/Vis absorption and fluorescence spectroscopy combined with DFT calculation. Compared with their parent all‐carbon analogs, the obtained B‐PAs exhibit high stability, wide energy gaps, and high photoluminescence quantum yields of up to 84 %. This study reveals the exceptional ability of boron doping to finely tune the physicochemical properties of PAs, showcasing their potential applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Die elektrochemische Protonenspeicherung spielt eine wesentliche Rolle bei der Entwicklung von hochleistungsfähigen Energiespeichern der nächsten Generation, z. B. von wasserbasierten Batterien. Zweidimensionale konjugierte kovalente organische Gerüstverbindungen (2D c‐COFs) sind vielversprechende Elektrodenmaterialien, aber ihre Protonen‐ und Metallionen‐Insertionsmechanismen sind nach wie vor schwer zu beschreiben, die Protonenspeicherung in COFs ist kaum erforscht. Hier stellen wir ein auf Perinon‐basiertes Poly(benzimidazobenzophenanthrolin) (BBL)‐Leiter‐2D c‐COF zur schnellen Protonenspeicherung sowohl in einem milden wässrigen Zn‐Ionen‐Elektrolyt als auch in einer starken Säure vor. Wir zeigen, dass die entladenen C−O− Gruppen aufgrund der beträchtlichen π‐Delokalisierung in Perinon eine weitgehend reduzierte Basizität aufweisen, was dem 2D c‐COF eine besondere Affinität zu Protonen verleiht sowie in schneller Kinetik resultiert. Dadurch weist unsere 2D c‐COF‐Elektrode eine herausragende Ratenfähigkeit bis 200 A g−1 (über 2500 C) auf und übertrifft damit bisherige konjugierten Polymere, COFs und metallorganischen Gerüstverbindungen. Unsere Arbeit ist das erste Beispiel für reine Protonenspeicherung in COFs und unterstreicht das große Potenzial von konjugierten 2D‐BBL‐Leiterer‐Polymeren für zukünftige energetische Anwendungen. [ABSTRACT FROM AUTHOR]

Electrochemical proton storage plays an essential role in designing next‐generation high‐rate energy storage devices, e.g., aqueous batteries. Two‐dimensional conjugated covalent organic frameworks (2D c‐COFs) are promising electrode materials, but their competitive proton and metal‐ion insertion mechanisms remain elusive, and proton storage in COFs is rarely explored. Here, we report a perinone‐based poly(benzimidazobenzophenanthroline) (BBL)‐ladder‐type 2D c‐COF for fast proton storage in both a mild aqueous Zn‐ion electrolyte and strong acid. We unveil that the discharged C−O− groups exhibit largely reduced basicity due to the considerable π‐delocalization in perinone, thus affording the 2D c‐COF a unique affinity for protons with fast kinetics. As a consequence, the 2D c‐COF electrode presents an outstanding rate capability of up to 200 A g−1 (over 2500 C), surpassing the state‐of‐the‐art conjugated polymers, COFs, and metal–organic frameworks. Our work reports the first example of pure proton storage among COFs and highlights the great potential of BBL‐ladder‐type 2D conjugated polymers in future energy devices. [ABSTRACT FROM AUTHOR]

As there are many uncertain factors in the geological hazard risk, great challenges are brought to the comprehensive evaluation of it. In order to improve the comprehensiveness and accuracy of geological hazard risk assessment, a cloud fuzzy clustering algorithm is constructed in this paper, which can effectively estimate and evaluate uncertain variables. The weight value of the risk cloud droplets is calculated as the input. By setting up clustering conditions and function output conditions, the cluster weights of the inputs which meet requirements can be obtained by multiple clustering iterations. Through the introduction of time parameters, the influence of time factors on data importance and the risk severity of geological disaster emergencies are fully considered. The experimental results show that the calculated risk degree cluster weights are less than 1, which verifies the feasibility and practicability of the algorithm. The research in this paper shows that the clustering dynamic assessment of geological hazards can help to improve the accuracy of risk assessment and provide reference and help for the prevention and control of regional geological hazards. [ABSTRACT FROM AUTHOR]

Die atomgenaue Synthese von helikalen mehrschichtigen Nanographenen (NG) neuer Topologie ist aufgrund ihrer exotischen physikochemischen Eigenschaften von substanziellem Interesse. Allerdings ist die Synthese dieser Nanographene, speziell mit nicht benzoiden Ringen, äußerst herausfordernd. Wir präsentieren in diesem Artikel die effiziente Synthese des ersten helikalen zweischichtigen nichtbenzoiden Nanographens (HBNG1) ausgehend von einem maßgeschneiderten Azulen‐Vorläufer, welcher bereits das neuartige Strukturelement zweier in [10]Helicen eingebetteter heptagonaler Ringe enthält. Die Einkristalldiffraktometrie gibt Einblick in die sterisch stark gespannte Doppelschichtstruktur mit einem Rekordwert für den kleinsten Interschichtabstand von nur 3.2 Å, in der Substanzklasse der doppelschichtigen Nanographene. Bemerkenswerterweise kommt es im Raum zwischen den Schichten zu π–π Wechselwirkungen. Wir untersuchten diesen Effekt durch in situ Spektroelektrochemie und Simulationen mittels Dichtefunktionaltheorie (DFT). Des Weiteren wurden die chiroptischen Eigenschaften der P/M‐Enantiomere von HBNG1 durch Zirkulardichroismus und zirkular polarisierter Fluoreszenz charakterisiert. [ABSTRACT FROM AUTHOR]

The precision synthesis of helical bilayer nanographenes (NGs) with new topology is of substantial interest because of their exotic physicochemical properties. However, helical bilayer NGs bearing non‐hexagonal rings remain synthetically challenging. Here we present the efficient synthesis of the first helical bilayer nonbenzenoid nanographene (HBNG1) from a tailor‐made azulene‐embedded precursor, which contains a novel [10]helicene backbone with two embedded heptagons. Single‐crystal X‐ray analysis reveals its highly twisted bilayer geometry with a record small interlayer distance of 3.2 Å among the reported helical bilayer NGs. Notably, the close interlayer distance between the two layers offers intramolecular through‐space conjugation as revealed by in situ spectroelectrochemistry studies together with DFT simulations. Furthermore, the chiroptical properties of the P/M enantiomers of HBNG1 are also evaluated by circular dichroism and circularly polarized luminescence. [ABSTRACT FROM AUTHOR]

Reverberation is a key limitation factor for improving sonar detection performance. In this paper, a novel method taking advantage of the symmetrical signal which is named Flip Array Conventional Beamforming method is proposed to suppress reverberation. First, in centrosymmetric arrays, the array-time-flipped snapshot matrix is constructed by rotating the temporal snapshot matrix of the centrosymmetric array 180°. Compared with the temporal snapshot matrix, the echo delay of the corresponding row in the array-time-flipped snapshot matrix is unchanged, but the waveform is flipped. The matching covariance matrix is the cross-correlation of the temporal snapshot matrix and the array-time-flipped snapshot matrix. Second, any waveform can be decomposed into a temporal symmetrical sub-waveform and temporal odd symmetrical sub-waveform. Through active sonar waveform design, the signal has only symmetrical sub-waveform, random reverberation has two sub-waveforms. The cross-correlation power of the signal and its time-flipped signal is equal to its power, while that of reverberation is the difference of the two sub-waveforms' power which is less than the reverberation's power. So reverberation can be suppressed by using the matching covariance matrix for beamforming. An experiment was conducted in an artificial lake, and the proposed approach was applied to the experimental data, compared with the conventional method, the average value of the reverberation spatial spectrum of the proposed method is reduced by about 5 dB. • The cross-correlation between time domain symmetric signal and its time flipped is its power. • The cross-correlation between reverberation and its time flipped is less than its power. • Rotation of data matrix received by a Centrosymmetric array by 180° will only flip the waveform. • We use the above three points to achieve reverberation suppression when DOA. [ABSTRACT FROM AUTHOR]

Open‐shell non‐alternant polycyclic hydrocarbons (PHs) are attracting increasing attention due to their promising applications in organic spintronics and quantum computing. Herein we report the synthesis of three cyclohepta[def]fluorene‐based diradicaloids (1–3), by fusion of benzo rings on its periphery for the thermodynamic stabilization, as evidenced by multiple characterization techniques. Remarkably, all of them display a very narrow optical energy gap (Egopt=0.52–0.69 eV) and persistent stability under ambient conditions (t1/2=11.7–33.3 h). More importantly, this new type of diradicaloids possess a low‐lying triplet state with an extremely small singlet–triplet energy gap, as low as 0.002 kcal mol−1, with a clear dependence on the molecular size. This family of compounds thus offers a new route to create non‐alternant open‐shell PHs with high‐spin ground states, and opens up novel possibilities and insights into understanding the structure–property relationships. [ABSTRACT FROM AUTHOR]

Open‐shell non‐alternant polycyclic hydrocarbons (PHs) are attracting increasing attention due to their promising applications in organic spintronics and quantum computing. Herein we report the synthesis of three cyclohepta[def]fluorene‐based diradicaloids (1–3), by fusion of benzo rings on its periphery for the thermodynamic stabilization, as evidenced by multiple characterization techniques. Remarkably, all of them display a very narrow optical energy gap (Egopt=0.52–0.69 eV) and persistent stability under ambient conditions (t1/2=11.7–33.3 h). More importantly, this new type of diradicaloids possess a low‐lying triplet state with an extremely small singlet–triplet energy gap, as low as 0.002 kcal mol−1, with a clear dependence on the molecular size. This family of compounds thus offers a new route to create non‐alternant open‐shell PHs with high‐spin ground states, and opens up novel possibilities and insights into understanding the structure–property relationships. [ABSTRACT FROM AUTHOR]

Vinylene‐linked two‐dimensional conjugated covalent organic frameworks (V‐2D‐COFs), belonging to the class of two‐dimensional conjugated polymers, have attracted increasing attention due to their extended π‐conjugation over the 2D backbones associated with high chemical stability. The Knoevenagel polycondensation has been demonstrated as a robust synthetic method to provide cyano (CN)‐substituted V‐2D‐COFs with unique optoelectronic, magnetic, and redox properties. Despite the successful synthesis, it remains elusive for the relevant polymerization mechanism, which leads to relatively low crystallinity and poor reproducibility. In this work, we demonstrate the novel synthesis of CN‐substituted V‐2D‐COFs via the combination of Knoevenagel polycondensation and water‐assisted dynamic Michael‐addition‐elimination, abbreviated as KMAE polymerization. The existence of C=C bond exchange between two diphenylacrylonitriles (M1 and M6) is firstly confirmed via in situ high‐temperature NMR spectroscopy study of model reactions. Notably, the intermediate M4 synthesized via Michael‐addition can proceed the Michael‐elimination quantitatively, leading to an efficient C=C bond exchange, unambiguously confirming the dynamic nature of Michael‐addition‐elimination. Furthermore, the addition of water can significantly promote the reaction rate of Michael‐addition‐elimination for highly efficient C=C bond exchange within 5 mins. As a result, the KMAE polymerization provides a highly efficient strategy for the synthesis of CN‐substituted V‐2D‐COFs with high crystallinity, as demonstrated by four examples of V‐2D‐COF‐TFPB‐PDAN, V‐2D‐COF‐TFPT‐PDAN, V‐2D‐COF‐TFPB‐BDAN, and V‐2D‐COF‐HATN‐BDAN, based on the simulated and experimental powder X‐ray diffraction (PXRD) patterns as well as N2‐adsorption–desorption measurements. Moreover, high‐resolution transmission electron microscopy (HR‐TEM) analysis shows crystalline domain sizes ranging from 20 to 100 nm for the newly synthesized V‐2D‐COFs. [ABSTRACT FROM AUTHOR]

Vinylene‐linked two‐dimensional conjugated covalent organic frameworks (V‐2D‐COFs), belonging to the class of two‐dimensional conjugated polymers, have attracted increasing attention due to their extended π‐conjugation over the 2D backbones associated with high chemical stability. The Knoevenagel polycondensation has been demonstrated as a robust synthetic method to provide cyano (CN)‐substituted V‐2D‐COFs with unique optoelectronic, magnetic, and redox properties. Despite the successful synthesis, it remains elusive for the relevant polymerization mechanism, which leads to relatively low crystallinity and poor reproducibility. In this work, we demonstrate the novel synthesis of CN‐substituted V‐2D‐COFs via the combination of Knoevenagel polycondensation and water‐assisted dynamic Michael‐addition‐elimination, abbreviated as KMAE polymerization. The existence of C=C bond exchange between two diphenylacrylonitriles (M1 and M6) is firstly confirmed via in situ high‐temperature NMR spectroscopy study of model reactions. Notably, the intermediate M4 synthesized via Michael‐addition can proceed the Michael‐elimination quantitatively, leading to an efficient C=C bond exchange, unambiguously confirming the dynamic nature of Michael‐addition‐elimination. Furthermore, the addition of water can significantly promote the reaction rate of Michael‐addition‐elimination for highly efficient C=C bond exchange within 5 mins. As a result, the KMAE polymerization provides a highly efficient strategy for the synthesis of CN‐substituted V‐2D‐COFs with high crystallinity, as demonstrated by four examples of V‐2D‐COF‐TFPB‐PDAN, V‐2D‐COF‐TFPT‐PDAN, V‐2D‐COF‐TFPB‐BDAN, and V‐2D‐COF‐HATN‐BDAN, based on the simulated and experimental powder X‐ray diffraction (PXRD) patterns as well as N2‐adsorption–desorption measurements. Moreover, high‐resolution transmission electron microscopy (HR‐TEM) analysis shows crystalline domain sizes ranging from 20 to 100 nm for the newly synthesized V‐2D‐COFs. [ABSTRACT FROM AUTHOR]

Using an efficient synthetic strategy,a novel class of 1,2-diazine-embeddedperylenes, namely 1,2,7,8-tetraazaperylene derivatives, have beensuccessfully synthesized. These molecules were fully characterizedby X-ray diffraction analysis, optical spectroscopy, and electrochemistry.The low-lying lowest unoccupied molecular orbital (LUMO) level ofthese molecules suggests their potential as good electronic acceptors. [ABSTRACT FROM AUTHOR]

Rechargeable aluminium (Al) batteries (RABs) have long‐been pursued due to the high sustainability and three‐electron‐transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al–amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3N.+ or R4N+) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al–amine battery exhibits a high reversible capacity of 135 mAh g−1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al–amine battery shows excellent stability against self‐discharge, far beyond conventional Al–graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance. [ABSTRACT FROM AUTHOR]

Rechargeable aluminium (Al) batteries (RABs) have long‐been pursued due to the high sustainability and three‐electron‐transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al–amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3N.+ or R4N+) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al–amine battery exhibits a high reversible capacity of 135 mAh g−1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al–amine battery shows excellent stability against self‐discharge, far beyond conventional Al–graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance. [ABSTRACT FROM AUTHOR]

A novel synthetic strategy was developed for the construction of difficult‐to‐access structurally constrained boron‐doped polycyclic aromatic hydrocarbons (sc‐B‐PAHs) via a cascade reaction from the readily available ortho‐aryl‐substituted diarylalkynes. This domino process involves borylative cyclization, 1,4‐boron migration and successive two‐fold electrophilic borylation. Two types of sc‐B‐PAHs bearing B‐doped [4]helicene (1 a‐1 i) or BN‐doped [4]helicene (1 n‐1 t) and double [4]helicene (1 u‐1 v) are constructed by this cascade reaction. Remarkably, this synthetic strategy is characterized by modest yields (20–50 %) and broad substrate scope (18 examples) with versatile functional group tolerance. The resultant sc‐B‐PAHs show good stability under ambient conditions and are thoroughly investigated by X‐ray crystallography, UV/Vis absorption and fluorescence spectroscopy, and cyclic voltammetry. Interestingly enough, BN‐doped [4]helicene 1 o forms a unique alternating π‐stacked dimer of enantiomers within a helical columnar superstructure, while BN‐doped double [4]helicene 1 u establishes an unprecedented π‐stacked trimeric sandwich structure with a rare 2D lamellar π‐stacking. The synthetic approach reported herein represents a powerful tool for the rapid generation of novel sc‐B‐PAHs, which are highly attractive for the elucidation of the structure‐property relationship and for potential optoelectronic applications. [ABSTRACT FROM AUTHOR]

A novel synthetic strategy was developed for the construction of difficult‐to‐access structurally constrained boron‐doped polycyclic aromatic hydrocarbons (sc‐B‐PAHs) via a cascade reaction from the readily available ortho‐aryl‐substituted diarylalkynes. This domino process involves borylative cyclization, 1,4‐boron migration and successive two‐fold electrophilic borylation. Two types of sc‐B‐PAHs bearing B‐doped [4]helicene (1 a‐1 i) or BN‐doped [4]helicene (1 n‐1 t) and double [4]helicene (1 u‐1 v) are constructed by this cascade reaction. Remarkably, this synthetic strategy is characterized by modest yields (20–50 %) and broad substrate scope (18 examples) with versatile functional group tolerance. The resultant sc‐B‐PAHs show good stability under ambient conditions and are thoroughly investigated by X‐ray crystallography, UV/Vis absorption and fluorescence spectroscopy, and cyclic voltammetry. Interestingly enough, BN‐doped [4]helicene 1 o forms a unique alternating π‐stacked dimer of enantiomers within a helical columnar superstructure, while BN‐doped double [4]helicene 1 u establishes an unprecedented π‐stacked trimeric sandwich structure with a rare 2D lamellar π‐stacking. The synthetic approach reported herein represents a powerful tool for the rapid generation of novel sc‐B‐PAHs, which are highly attractive for the elucidation of the structure‐property relationship and for potential optoelectronic applications. [ABSTRACT FROM AUTHOR]

Nanographenes (NGs) can be embedded with predesigned dopants or nonhexagonal rings to tailor the electronic properties and provide ideal platforms to study the unique physical and chemical properties. Here, we report the on-surface synthesis of NBN-doped NG embedded with five- and seven-membered rings (NBN-575-NG) on Au(111) from a oligophenylene precursor preinstalled with a NBN unit and a heptagonal ring. Scanning tunneling microscopy and non-contact atomic force microscopy images elucidate the intramolecular cyclodehydrogenation and the existence of the five- and seven-membered rings. Scanning tunneling spectroscopy spectra reveal that the NBN-575-NG is a semiconductor, which agrees with the density functional theory calculation results on a freestanding NBN-575-NG with the same structure. This work provides a feasible approach for the on-surface synthesis of novel NGs containing non-hexagonal rings. [ABSTRACT FROM AUTHOR]