Soluble Nanographene C222: Synthesis and Applications for Synergistic Photodynamic/Photothermal Therapy.

Nanographene C222, which consists of a planar graphenic plane containing 222 carbon atoms, holds the record as the largest planar nanographene synthesized to date. However, its complete insolubility makes the processing of C222 difficult. Here we addressed this issue by introducing peripheral substituents perpendicular to the graphene plane, effectively disrupting the interlayer stacking and endowing C222 with good solubility. We also found that the electron-withdrawing substituents played a crucial role in the cyclodehydrogenation process, converting the dendritic polyphenylene precursor to C222. After disrupting the interlayer stacking, the introduction of only a few peripheral carboxylic groups allowed C222 to dissolve in phosphate buffer saline, reaching a concentration of up to 0.5 mg/mL. Taking advantage of the good photosensitizing and photothermal properties of the inner C222 core, the resulting water-soluble C222 emerged as a single-component agent for both photothermal and photodynamic tumor therapy, exhibiting an impressive tumor inhibition rate of 96%.

Pathogenic Mutation ΔK280 Promotes Hydrophobic Interactions Involving Microtubule-Binding Domain and Enhances Liquid-Liquid Phase Separation of Tau.

Liquid-liquid phase separation (LLPS) of tau protein can initiate its aggregation which is associated with Alzheimer's disease. The pathogenic mutation ΔK280 can enhance the aggregation of K18, a truncated tau variant comprising the microtubule-binding domain. However, the impact of ΔK280 on K18 LLPS and underlying mechanisms are largely unexplored. Herein, the conformational ensemble and LLPS of ΔK280 K18 through multiscale molecular simulations and microscopy experiments are investigated. All-atom molecular dynamic simulations reveal that ΔK280 significantly enhances the collapse degree and ß-sheet content of the K18 monomer, indicating that ΔK280 mutation may promote K18 LLPS, validated by coarse-grained phase-coexistence simulations and microscopy experiments. Importantly, ΔK280 mutation promotes ß-sheet formation of six motifs (especially PHF6), increases the hydrophobic solvent exposure of PHF6* and PHF6, and enhances hydrophobic, hydrogen bonding, and cation-π interactions involving most of the motifs, thus facilitating the phase separation of K18. Notably, ΔK280 alters the interaction network among the six motifs, inducing the formation of K18 conformations with high ß-sheet contents and collapse degree. Coarse-grained simulations on full-length tau reveal that ΔK280 promotes tau LLPS by enhancing the hydrophobic interactions involving the microtubule-binding domain. These findings offer detailed mechanistic insights into ΔK280-induced tau pathogenesis, providing potential targets for therapeutic intervention.

Optimized Intermediates Adsorption Configuration on Co-Doped Fe2P@NiP2 Heterojunction Interface for Enhanced Electrocatalytic Nitrate-To-Ammonia Conversion.

The extraction of ammonia (NH3) through electrocatalytic nitrate reduction reaction (NO3 -RR) represents a sustainable avenue in NH3 generation and utilization. However, the catalytic efficiency of the NO3 -RR is hindered by the sluggish kinetics. This study first theoretically found that phosphide-based heterostructure can alter the adsorption structure of intermediates in the nitrate-to-ammonia process, thereby achieving precise regulation of the energy barrier in the rate-determining step. Based on theoretical design, a novel Co-doped Fe2P@NiP2 heterojunction catalyst is successfully synthesized, which deliver a notable NH3 yield rate of 0.395 mmol h-1 cm-2 at -0.7 V versus RHE, as well as a remarkable ammonia Faraday efficiency of 97.2% at -0.6 V versus RHE. Experimental and theoretical results further confirm that redistributing electrons and shifting the center of the d-band upwards through interfacial doping modulate intermediates adsorption strength and inhibition of hydrogen evolution, leading to excellent performance in NO3 --to-NH3. Further integrating the Co-Fe2P@NiP2 catalyst into a Zn-nitrate battery exhibits a substantial voltage output of 1.49 V and a commendable power density of 13.2 mW cm-2. The heteroatom-doped heterojunction strategy provides a versatile route for developing advanced catalysts, thereby broadening the horizons of electrocatalytic methodologies for nitrate reduction and ammonia synthesis.

Immunoneoadjuvant therapy with immune checkpoint inhibitors of gastric cancer: an emerging exemplification : Immunoneoadjuvant therapy of gastric cancer.

Advances in immune checkpoint inhibitors (ICIs) have enabled more effective treatment for individuals with various types of solid tumors. Given the improved survival benefit and acceptable safety profile of ICIs in advanced gastric cancer, there is plenty of interest in the use of ICIs in the neoadjuvant setting with curative intent. Theoretically, immunoneoadjuvant with ICIs could boost the levels of endogenous tumor antigen present in the tumor to enhance T-cell priming and further enhance systemic immunity. This systemic immune response may improve the detection and elimination of the disseminated micrometastatic tumors beyond the resected tumor, which are sources of postsurgical relapse. Numerous clinical studies have begun to explore the application of ICIs in neoadjuvant treatment of gastric cancer. This article reviews the progress in the use of ICI monotherapy and in combination with alternative therapies for the treatment of gastric cancer to aid in the development of gastric cancer immunoneoadjuvant therapy and improve the overall therapeutic benefit.

Unraveling the potential biomarkers of immune checkpoint inhibitors in advanced ovarian cancer: a comprehensive review.

The ongoing research on the role of immunotherapy in advanced ovarian cancer (OC) and current clinical trials indicate that patients shown limited response to immune checkpoint inhibitor (ICI) monotherapy. When combined with other treatments or drugs, the efficacy of immunotherapy will be significantly improved. Biomarkers can be used to identify patients with better responses, thereby improving the precision and efficacy of immunotherapy. Key biomarkers for advanced OC include homologous repair deficiency, programmed death-ligand (PD-L) 1 expression, chemokines, and tumor infiltrating lymphocytes. These biomarkers could be applied in the future to select the most suitable patient populations. This review comprehensively examines the research and development of biomarkers in OC immunotherapy from three omics perspectives: genomics, transcriptomics, and proteomics, which may provide guidance for the effectiveness of OC immunotherapy strategies.

Melatonin improves influenza virus infection-induced acute exacerbation of COPD by suppressing macrophage M1 polarization and apoptosis.

BACKGROUND: Influenza A viruses (IAV) are extremely common respiratory viruses for the acute exacerbation of chronic obstructive pulmonary disease (AECOPD), in which IAV infection may further evoke abnormal macrophage polarization, amplify cytokine storms. Melatonin exerts potential effects of anti-inflammation and anti-IAV infection, while its effects on IAV infection-induced AECOPD are poorly understood. METHODS: COPD mice models were established through cigarette smoke exposure for consecutive 24 weeks, evaluated by the detection of lung function. AECOPD mice models were established through the intratracheal atomization of influenza A/H3N2 stocks in COPD mice, and were injected intraperitoneally with melatonin (Mel). Then, The polarization of alveolar macrophages (AMs) was assayed by flow cytometry of bronchoalveolar lavage (BAL) cells. In vitro, the effects of melatonin on macrophage polarization were analyzed in IAV-infected Cigarette smoking extract (CSE)-stimulated Raw264.7 macrophages. Moreover, the roles of the melatonin receptors (MTs) in regulating macrophage polarization and apoptosis were determined using MTs antagonist luzindole. RESULTS: The present results demonstrated that IAV/H3N2 infection deteriorated lung function (reduced FEV20,50/FVC), exacerbated lung damages in COPD mice with higher dual polarization of AMs. Melatonin therapy improved airflow limitation and lung damages of AECOPD mice by decreasing IAV nucleoprotein (IAV-NP) protein levels and the M1 polarization of pulmonary macrophages. Furthermore, in CSE-stimulated Raw264.7 cells, IAV infection further promoted the dual polarization of macrophages accompanied with decreased MT1 expression. Melatonin decreased STAT1 phosphorylation, the levels of M1 markers and IAV-NP via MTs reflected by the addition of luzindole. Recombinant IL-1ß attenuated the inhibitory effects of melatonin on IAV infection and STAT1-driven M1 polarization, while its converting enzyme inhibitor VX765 potentiated the inhibitory effects of melatonin on them. Moreover, melatonin inhibited IAV infection-induced apoptosis by suppressing IL-1ß/STAT1 signaling via MTs. CONCLUSIONS: These findings suggested that melatonin inhibited IAV infection, improved lung function and lung damages of AECOPD via suppressing IL-1ß/STAT1-driven macrophage M1 polarization and apoptosis in a MTs-dependent manner. Melatonin may be considered as a potential therapeutic agent for influenza virus infection-induced AECOPD.

Topologically Localized Vibronic Excitations in Second-Layer Graphene Nanoribbons.

It is of fundamental importance to characterize the intrinsic properties, like the topological end states, in the on-surface synthesized graphene nanoribbons (GNRs), but the strong electronic interaction with the metal substrate usually smears out their characteristic features. Here, we report our approach to investigate the vibronic excitations of the topological end states in self-decoupled second-layer GNRs, which are grown using an on-surface squeezing-induced spillover strategy. The vibronic progressions show highly spatially localized distributions at the second-layer GNR ends, which can be ascribed to the decoupling-extended lifetime of charging through resonant electron tunneling at the topological end states. In combination with theoretical calculations, we assign the vibronic progressions to specific vibrational modes that mediate the vibronic excitations. The spatial distribution of each resolved excitation shows evident characteristics beyond the conventional Franck-Condon picture. Our work by direct growth of second-layer GNRs provides an effective way to explore the interplay between the intrinsic electronic, vibrational, and topological properties.

The mutational landscape of a US Midwestern breast cancer cohort reveals subtype-specific cancer drivers and prognostic markers.

BACKGROUND: Female breast cancer remains the second leading cause of cancer-related death in the USA. The heterogeneity in the tumor morphology across the cohort and within patients can lead to unpredictable therapy resistance, metastasis, and clinical outcome. Hence, supplementing classic pathological markers with intrinsic tumor molecular markers can help identify novel molecular subtypes and the discovery of actionable biomarkers. METHODS: We conducted a large multi-institutional genomic analysis of paired normal and tumor samples from breast cancer patients to profile the complex genomic architecture of breast tumors. Long-term patient follow-up, therapeutic regimens, and treatment response for this cohort are documented using the Breast Cancer Collaborative Registry. The majority of the patients in this study were at tumor stage 1 (51.4%) and stage 2 (36.3%) at the time of diagnosis. Whole-exome sequencing data from 554 patients were used for mutational profiling and identifying cancer drivers. RESULTS: We identified 54 tumors having at least 1000 mutations and 185 tumors with less than 100 mutations. Tumor mutational burden varied across the classified subtypes, and the top ten mutated genes include MUC4, MUC16, PIK3CA, TTN, TP53, NBPF10, NBPF1, CDC27, AHNAK2, and MUC2. Patients were classified based on seven biological and tumor-specific parameters, including grade, stage, hormone receptor status, histological subtype, Ki67 expression, lymph node status, race, and mutational profiles compared across different subtypes. Mutual exclusion of mutations in PIK3CA and TP53 was pronounced across different tumor grades. Cancer drivers specific to each subtype include TP53, PIK3CA, CDC27, CDH1, STK39, CBFB, MAP3K1, and GATA3, and mutations associated with patient survival were identified in our cohort. CONCLUSIONS: This extensive study has revealed tumor burden, driver genes, co-occurrence, mutual exclusivity, and survival effects of mutations on a US Midwestern breast cancer cohort, paving the way for developing personalized therapeutic strategies.

Probing σ-Aromaticity-Driven Ring Contraction of Metallabenzocyclobutadiene to Metallabenzocyclopropene.

Ring contraction of metallacyclobutadiene to metallacyclopropene is rare because of the increasing strain from a four-membered ring to a three-membered one. Here we demonstrate a new series of reactions of metallabenzocyclobutadiene to metallabenzocyclopropene via density functional theory calculations. The results suggest that these reactions are thermodynamically favorable ranging from -17.4 to -29.4 kcal mol-1, and a low reaction barrier (10.3 kcal mol-1) is achieved when the metal center is Ru and the ligands are one cyanide and one chloride. Further analysis suggests that a strengthened binding energy helps stabilize the transition state in the protonation process. The aromaticity during the reaction was investigated using the electron density of delocalized bonds (EDDB), isomerization stabilization energy, and isodesmic reactions. The EDDB shows that the π-conjugation is disrupted in the intermediate, and then σ-aromaticity is generated and dominant in the products. Our findings could be helpful for experimentalists in developing novel ring contraction reactions driven by aromaticity.

YAP inhibition overcomes adaptive resistance in HER2-positive gastric cancer treated with trastuzumab via the AKT/mTOR and ERK/mTOR axis.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) is a heterogeneous GC subtype characterized by the overexpression of HER2. To date, few specific targeted therapies have demonstrated durable efficacy in HER2-positive GC patients, with resistance to trastuzumab typically emerging within 1 year. However, the mechanisms of resistance to trastuzumab remain incompletely understood, presenting a significant challenge to clinical practice. METHODS: In this study, we integrated genetic screening and bulk transcriptome and epigenomic profiling to define the mechanisms mediating adaptive resistance to HER2 inhibitors and identify potential effective therapeutic strategies for treating HER2-positive GCs. RESULTS: We revealed a potential association between adaptive resistance to trastuzumab in HER2-positive GC and the expression of YES-associated protein (YAP). Notably, our investigation revealed that long-term administration of trastuzumab triggers extensive chromatin remodeling and initiates YAP gene transcription in HER2-positive cells characterized by the initial inhibition and subsequent reactivation. Furthermore, treatment of HER2-positive GC cells and cell line-derived xenografts (CDX) models with YAP inhibitors in combination with trastuzumab was found to induce synergistic effects through the AKT/mTOR and ERK/mTOR pathways. CONCLUSION: These findings underscore the pivotal role of reactivated YAP and mTOR signaling pathways in the development of adaptive resistance to trastuzumab and may serve as a promising joint target to overcome resistance to trastuzumab.

Performance evaluation of a novel high-sensitivity cardiac troponin T assay: analytical and clinical perspectives.

OBJECTIVES: To evaluate the analytical characteristics of a novel high-sensitivity cardiac troponin T (hs-cTnT) test on the automatic light-initiated chemiluminescent assay (LiCA®) system, and validated its diagnostic performance for non-ST-segment elevation myocardial infarction (NSTEMI). METHODS: Studies included an extensive analytical evaluation and established the 99th percentile upper reference limit (URL) from apparently healthy individuals, followed by a diagnostic performance validation for NSTEMI. RESULTS: Sex-specific 99th percentile URLs were 16.0 ng/L (1.7 % CV: coefficient of variation) for men (21-92 years) and 13.4 ng/L (2.0 % CV) for women (23-87 years) in serum, and 30.6 ng/L (0.9 % CV) for men (18-87 years) and 20.2 ng/L (1.4 % CV) for women (18-88 years) in heparin plasma. Detection rates in healthy individuals ranged from 98.9 to 100 %. An excellent agreement was identified between LiCA® and Elecsys® assays with a correlation coefficient of 0.993 and mean bias of -0.7 % (-1.8-0.4 %) across the full measuring range, while the correlation coefficient and overall bias were 0.967 and -1.1 % (-2.5-0.3 %) for the lower levels of cTnT (10-100 ng/L), respectively. At the specific medical decision levels (14.0 and 52.0 ng/L), assay difference was estimated to be <5.0 %. No significant difference was found between these two assays in terms of area under curve (AUC), sensitivity and specificity, negative predictive value (NPV) and positive predictive value (PPV) for the diagnosis of NSTEMI. CONCLUSIONS: LiCA® hs-cTnT is a reliable 3rd-generation (level 4) high-sensitivity assay for detecting cardiac troponin T. The assay is acceptable for practical use in the diagnosis of NSTEMI.

The Expression and Clinical Significance of USF1 in Newly Diagnosed Acute Myeloid Leukemia.

BACKGROUND: This study aimed to assess the expression level of upstream stimulator 1 (USF1) in the bone marrow of newly diagnosed acute myeloid leukemia (AML) patients and investigate its clinical and prognostic significance. METHODS: Bone marrow samples from 60 newly diagnosed AML patients constituted the observation group, while 20 samples from healthy individuals formed the control group. Real-time quantitative PCR (qRT-PCR) was used to measure the USF1 expression in both groups and to analyze its correlation with clinicopathological features and prognosis in AML patients. Kaplan-Meier curves were utilized to assess the impact of USF1 on the overall survival (OS) in AML patients. The prognostic factors of AML were examined by using Cox regression analysis. RESULTS: A univariate analysis revealed a significantly higher USF1 expression in the AML patients compared to the control group (p < 0.001), with no difference in the clinicopathological features between the low-expression group and the control group. However, there was a significant difference between the high-expression group and the control group (p < 0.01). Moreover, the OS of the high USF1 expression group was notably shorter than of the low USF1 expression group (p < 0.0001). A multivariate analysis identified high USF1 expression and age ≥ 60 years as independent risk factors for a poor AML prognosis. CONCLUSIONS: High expression of USF1 is linked to a worse prognosis and shorter survival time in AML patients. USF1 may serve as an indicator of prognosis and survival in AML patients and could be a potential target for AML treatment.

Expression of CDK9 in Newly Diagnosed Patients with Acute Myeloid Leukemia and its Clinical Significance.

BACKGROUND: This study investigated the role of cyclin-dependent kinase 9 (CDK9) expression levels and prognosis in acute myeloid leukemia (AML) by examining its expression at the time of initial diagnosis. METHODS: Bone marrow samples from 60 AML patients were collected for the observation group, with 20 normal human bone marrow samples serving as controls. Clinical and pathological data were gathered from the AML pa-tients. Real-time quantitative PCR (RT-qPCR) was employed to measure CDK9 expression levels in both groups, and the association between CDK9 expression, clinical characteristics, and prognosis in AML patients was analyzed. Kaplan-Meier curves were used to assess the impact of CDK9 on overall survival (OS) in AML, while Cox regression analysis was performed to identify prognostic factors in AML patients. RESULTS: The expression of CDK9 was significantly elevated in AML patients, compared to the control group (p < 0.05). High CDK9 expression was associated with increased white blood cell (WBC) count, poor treatment response, and worse prognosis compared to low expression (p < 0.05). Additionally, patients with high CDK9 expression exhibited significantly shortened OS compared to those with low expression (p < 0.05). High CDK9 expression emerged as an independent risk factor influencing prognosis in AML. CONCLUSIONS: CDK9 is markedly upregulated in AML patients, suggesting its potential utility as both a prognostic indicator and a therapeutic target, particularly for patients with unfavorable clinical and pathological characteristics and poor prognosis.

Au-Based Bimetallic Catalysts for Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid under Base-Free Reaction Conditions.

The aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) plays a pivotal role in the synthesis of renewable, biodegradable plastics and sustainable chemicals. Although supported gold nanoclusters (NCs) exhibit significant potential in this process, they often suffer from low selectivity. To address this challenge, a series of gold-M (M means Ni, Fe, Cu, and Pd) bimetallic NCs catalysts were designed and synthesized to facilitate the selective oxidation of HMF to FDCA. Our findings indicate that the introduction of doped metals, particularly Ni and Pd, not only improves the reaction rates for HMF tandem oxidation but also promotes high yields of FDCA. Various characterizations techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy of CO adsorption (CO-DRIFTS), and temperature-programmed desorption of oxygen (O2-TPD), were employed to scrutinize the structural and electronic properties of the prepared catalysts. Notably, an electronic effect was observed across the Au-based bimetallic catalysts, facilitating the activation of reactant molecules and enhancing the catalytic performance. This study provides valuable insights into the alloy effects, aiding in the development of highly efficient Au-based bimetallic catalysts for biomass conversions.

Involvement of mitochondrial TRPV3 in cardiac hypertrophy induced by pressure overload in rats.

Mitochondria play an important role in pressure overload-induced cardiac hypertrophy. The present study aimed to investigate the role of mitochondrial transient receptor potential vanilloid 3 (TRPV3) in myocardial hypertrophy. A 0.7 mm diameter U-shaped silver clip was used to clamp the abdominal aorta of Sprague Dawley (SD) rats and establish an animal model of abdominal aortic constriction (AAC). Rat H9C2 myocardial cells were treated with angiotensin II (Ang II) to establish a hypertrophic myocardial cell model, and TRPV3 expression was knocked down using TRPV3 small interfering RNA (siRNA). JC-1 probe was used to detect mitochondrial membrane potential (MMP). DHE probe was used to detect ROS generation. Enzyme activities of mitochondrial respiratory chain complex I and III and ATP production were detected by assay kits. Immunofluorescence staining was used to detect TRPV3 expression in H9C2 cells. Western blot was used to detect the protein expression levels of ß-myosin heavy chain (ß-MHC), mitochondrial TRPV3 and mitochondrial NOX4. The results showed that, in the rat AAC model heart tissue and H9C2 cells treated with Ang II, the protein expression levels of ß-MHC, mitochondrial TRPV3 and mitochondrial NOX4 were up-regulated, MMP was decreased, ROS generation was increased, mitochondrial respiratory chain complex I and III enzyme activities were decreased, and ATP production was reduced. After knocking down mitochondrial TRPV3 in H9C2 cells, the protein expression levels of ß-MHC and mitochondrial NOX4 were down-regulated, MMP was increased, ROS generation was decreased, mitochondrial respiratory chain complex I and III enzyme activities were increased, and ATP production was increased. These results suggest that mitochondrial TRPV3 in cardiomyocytes exacerbates mitochondrial dysfunction by up-regulating NOX4, thereby participating in the process of pressure overload-induced myocardial hypertrophy.

Improved Nitrate-to-Ammonia Electrocatalysis through Hydrogen Poisoning Effects.

Electrochemical conversion from nitrate to ammonia is a key step in sustainable ammonia production. However, it suffers from low productive efficiency or high energy consumption due to a lack of desired electrocatalysts. Here we report nickel cobalt phosphide (NiCoP) catalysts for nitrate-to-ammonia electrocatalysis that display a record-high catalytic current density of -702±7 mA cm-2, ammonia production rate of 5415±26 mmol gcat -1 h-1 and Faraday efficiency of 99.7±0.2 % at -0.3 V vs. RHE, affording the estimated energy consumption as low as 22.7 kWh kgammonia -1. Theoretical and experimental results reveal that these catalysts benefit from hydrogen poisoning effects, which leave behind catalytically inert adsorbed hydrogen species (HI*) at Co-hollow sites and thereupon enable ideally reactive HII* at secondary Co-P sites. The dimerization between HI* and HII* for H2 evolution is blocked due to the catalytic inertia of HI* thereby the HII* drives nitrate hydrogenation timely. With these catalysts, the continuous ammonia production is further shown in an electrolyser with a real energy consumption of 18.9 kWh kgammonia -1.

Nanographene with a Nitrogen-Doped Cavity.

Nitrogen-doped cavities are pervasive in graphenic materials, and represent key sites for catalytic and electrochemical activity. However, their structures are generally heterogeneous. In this study, we present the synthesis of a well-defined molecular cutout of graphene featuring N-doped cavity. The graphitization of a macrocyclic pyridinic precursor was achieved through photochemical cyclodehydrochlorination. In comparison to its counterpart with pyridinic nitrogen at the edges, the pyridinic nitrogen atoms in this nanographene cavity exhibit significantly reduced basicity and selective binding to Ag+ ion. Analysis of the protonation and coordination equilibria revealed that the tri-N-doped cavity binds three protons, but only one Ag+ ion. These distinct protonation and coordination behaviors clearly illustrate the space confinement effect imparted by the cavities.

Helical Nanographenes Bearing Pentagon-Heptagon Pairs by Stepwise Dehydrocyclization.

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

π-Extension of a Multiple Resonance Core: Double Helical and Heptagon-Embedded Nanographenes.

Multiple resonance (MR) boron-nitrogen doped polycyclic aromatic hydrocarbons (BN-PAHs) have shown compelling thermally activated delayed fluorescence (TADF), surpassing those of their hydrocarbon analogues. However, the structural variety of π-extended BN-PAHs remains narrow. In this study, we synthesized three double helical BN-doped nanographenes (BN-NGs), 2 a-2 c, and three heptagon-embedded BN-NGs, 1 a-1 c, by π-extension of the MR core. During the formation of 2 a, a nanographene with one heptagon (1 a) was obtained, whereas further dehydrocyclization of the [6]helicene units within 2 b and 2 c led to heptagon structures, yielding other two BN-NGs containing double heptagons (1 b and 1 c). These BN-NGs (2 a-2 c and 1 a-1 c) showed pronounced redshifts of 100-190 nm compared to the parent MR core, while preserving the TADF characteristics and prolonging the delayed fluorescence lifetime to the millisecond level. Furthermore, the integration of a heptagon ring into 1 a-1 c expanded the conjugation, reduced the oxidation potentials, and yielded a more flexible framework compared to those of 2 a-2 c. The enantiomers of 2 a-2 c, 1 a, and 1 c were resolved and their chiroptical properties were studied. Notably, 1 a and 1 c exhibited increased chiroptical dissymmetry factors.

Helical Trilayer Nanographenes with Tunable Interlayer Overlaps.

The synthesis of well-defined nanocarbon multilayers, beyond the bilayer structure, is still a challenging goal. Herein, two trilayer nanographenes were synthesized by covalently linking nanographene layers through helicene bridges. The structural characterization of the trilayer nanographenes revealed a compact trilayer-stacked architecture. The introduction of a furan ring into the helicene linker modulates the interlayer overlap and π-conjugation of the trilayer nanographenes, enabling the tuning of the interlayer coupling, as demonstrated by optical, electrochemical, and theoretical analyses. Both synthesized trilayer nanographenes are rigid chiral nanocarbons and show a chirality transfer from the helicene moiety to the stacked nanographene layers. These helical trilayer nanographenes reported here represent the covalently linked multilayer nanographenes rather than bilayer ones, showing the tunable multilayer stacking structure.