Narrow-Pore Engineering of Vinylene-Linked Covalent Organic Frameworks with Weak Interaction-Triggered Multiple Responses.

Vinylene-linked covalent organic frameworks (COFs) are emerging as promising crystalline materials, but their narrow pore engineering is severely impeded by the weak reversibility of the carbon-carbon double bond formation reaction, which has led to less exploration of their ultramicroporous structures and properties. Herein, we developed a single aromatic ring-based tetratopic monomer, tetramethylpyrazine, which undergoes a smooth Knoevenegal condensation at its four arylmethly carbon atoms with linear aromatic dialdehyde monomers upon the self-catalyzed activation of pyridine nitrogen-containing monomers in the presence of an organic anhydride. This has resulted in the formation of two vinylene-linked COFs, which both crystallized in orthorhombic lattices, and layered in AA stacking fashions along the vertical directions. They exhibit high surface areas and well-tailored ultramicropore sizes up to 0.5 nm. The unique cross-linking mode at two pairs of para-positions of each pyrazine unit through carbon-carbon double bonds afford them with π-extended conjugation over the in-plane backbones and substantial semiconducting characters. The resultant COFs can be well-dispersed in water to form stable sub-microparticles with negative charges (zeta potentials: ca. -30 mV), and exhibiting tunable aggregation behaviors through protonation/deprotonation. As a consequence, they exhibit pore-size-dependent colorimetric responses to various anions with different pKa values in high selectivity.

A model incorporating serum C3 complement levels may be useful for diagnosing biliary atresia in infants.

INTRODUCTION: Correctly identifying patients with biliary atresia (BA), while avoiding invasive diagnostic methods is challenging. The purpose of this study was to determine the value of serum immune indicators for distinguishing BA from other causes of cholestasis in infants. PATIENTS AND METHODS: The data of infants with a surgical/histological diagnosis of BA and those with other causes of cholestatic jaundice were retrospectively analyzed. Patients were divided into a BA group and a cholestasis control (CC) group. Biochemical parameters, major lymphocyte subsets, immunoglobin and C3 and C4 complement levels were compared between the groups. RESULTS: A total of 129 infants with BA and 63 with other causes of cholestasis (CC control group) with a median age of 2.2 months were included in the analysis. The levels of CD3+ T cells, CD3+CD4+ T cells, and premature T cells and the levels of C3 and C4 were all significantly higher in the BA group compared to the CC group (all P<0.05). Pair-wise correlation analyses indicated that C3 and C4 had a significant positive correlation with γ-GT in the BA group, but not in the CC group. Five indices were found to be significantly associated with BA: stool color, globulin, γ-GT, C3 and C4. A model incorporating stool color, gamma-glutamyl transpeptidase level, and C3 level exhibited an area under the ROC curve (AUC) of 0.93, and a sensitivity of 93% and specificity of 83% for the diagnosis of BA. CONCLUSIONS: Models incorporating serum C3 levels may be useful for accurately diagnosing BA in infants.

Vinylene-Linked Covalent Organic Frameworks (COFs) with Symmetry-Tuned Polarity and Photocatalytic Activity.

The polarity of a semiconducting molecule affects its intrinsic photophysical properties, which can be tuned by varying the molecular geometry. Herein, we developed a D3h -symmetric tricyanomesitylene as a new monomer which could be reticulated into a vinylene-linked covalent organic framework (g-C54 N6 -COF) via Knoevenagel condensation with another D3h -symmetric monomer 2,4,6-tris(4'-formyl-biphenyl-4-yl)-1,3,5-triazine. Replacing tricyanomesitylene with a C2v -symmetric 3,5-dicyano-2,4,6-trimethylpyridine gave a less-symmetric vinylene-linked COF (g-C52 N6 -COF). The octupolar conjugated characters of g-C54 N6 -COF were reflected in its scarce solvatochromic effects either in ground or excited states, and endowed it with more promising semiconducting behavior as compared with g-C52 N6 -COF, such as enhanced light-harvesting and excellent photo-induced charge generation and separation. Along with the matched energy level, g-C54 N6 -COF enabled the two-half reactions of photocatalytic water splitting with an average O2 evolution rate of 51.0 µmol h-1 g-1 and H2 evolution rate of 2518.9 µmol h-1 g-1 . Such values are among the highest of state-of-the-art COF photocatalysts.

Evaluation of the learning curve of laparoscopic choledochal cyst excision and Roux-en-Y hepaticojejunostomy in children: CUSUM analysis of a single surgeon's experience.

INTRODUCTION: Laparoscopic cyst excision and Roux-en-Y hepaticojejunostomy is gaining popularity as a treatment for choledochal cyst (CDC) in children. However, the learning curve for this challenging laparoscopic procedure has not been addressed. The aim of this study is to determine the characteristics of the learning curve of this procedure. This may guide the training in institutions currently not using this technique. METHODS: A prospectively collected database comprising all medical records of the first 104 consecutive patients undergoing laparoscopic CDC excision and Roux-en-Y hepaticojejunostomy performed by one surgeon was studied. Multifactorial linear/logistic regression analysis was performed to identify patient-, surgeon-, and procedure-related factors associated with operating times, rates of adverse event, and length of postoperative stay. RESULTS: Cumulative sum analysis demonstrated a learning curve for laparoscopic choledochal cyst excision of 37 cases. Comparing the early with the late experiences (37 vs. 67 cases), the surgeon-specific outcomes significantly improved in terms of operating times (352 vs. 240 min; P < 0.001), postoperative complication rate (13.5 vs. 1.5 %; P = 0.02), and the length of hospital stay (9.4 vs. 7.8 days; P = 0.01). After multivariate analyses, independent predictors of operating times included the completion of the learning curve (CLC) (OR 0.68, 95 % CI 0.63-0.73) and adhesion score (ORmiddle 1.25, 95 % CI 1.08-1.45; ORhigh 1.40, 95 % CI 1.20-1.62; compared with the low score); significant predictors of perioperative adverse outcomes were CLC (OR 0.07, 95 % CI 0.02-0.34) and comorbidities prior to the surgery (OR 30.65, 95 % CI 1.71-549.63). The independent predictors of length of postoperative stay included CLC, preoperative comorbidities, and perioperative adverse events. CONCLUSIONS: CLC for laparoscopic choledochal cyst excision is 37 cases. After CLC, not only the operative time is reduced, the complications, adverse results, and the length of hospital stay all decreased significantly. The learning curve can be used as the basis for performance guiding the training.

Amorphous Phosphorus/Nitrogen-Doped Graphene Paper for Ultrastable Sodium-Ion Batteries.

As the most promising anode material for sodium-ion batteries (SIBs), elemental phosphorus (P) has recently gained a lot of interest due to its extraordinary theoretical capacity of 2596 mAh/g. The main drawback of a P anode is its low conductivity and rapid structural degradation caused by the enormous volume expansion (>490%) during cycling. Here, we redesigned the anode structure by using an innovative methodology to fabricate flexible paper made of nitrogen-doped graphene and amorphous phosphorus that effectively tackles this problem. The restructured anode exhibits an ultrastable cyclic performance and excellent rate capability (809 mAh/g at 1500 mA/g). The excellent structural integrity of the novel anode was further visualized during cycling by using in situ experiments inside a high-resolution transmission electron microscope (HRTEM), and the associated sodiation/desodiation mechanism was also thoroughly investigated. Finally, density functional theory (DFT) calculations confirmed that the N-doped graphene not only contributes to an increase in capacity for sodium storage but also is beneficial in regards to improved rate performance of the anode.

Predicted Quantum Topological Hall Effect and Noncoplanar Antiferromagnetism in K_{0.5}RhO_{2}.

The quantum anomalous Hall (QAH) phase is a two-dimensional bulk ferromagnetic insulator with a nonzero Chern number in the presence of spin-orbit coupling (SOC) but in the absence of applied magnetic fields. Associated metallic chiral edge states host dissipationless current transport in electronic devices. This intriguing QAH phase has recently been observed in magnetic impurity-doped topological insulators, albeit, at extremely low temperatures. Based on first-principles density functional calculations, here we predict that layered rhodium oxide K_{0.5}RhO_{2} in the noncoplanar chiral antiferromagnetic state is an unconventional three-dimensional QAH insulator with a large band gap and a Néel temperature of a few tens of Kelvins. Furthermore, this unconventional QAH phase is revealed to be the exotic quantum topological Hall effect caused by nonzero scalar spin chirality due to the topological spin structure in the system and without the need of net magnetization and SOC.

New scheme for braiding Majorana fermions.

Non-Abelian statistics can be achieved by exchanging two vortices in topological superconductors with each grabbing a Majorana fermion (MF) as zero-energy quasi-particle at the cores. However, in experiments it is difficult to manipulate vortices. In the present work, we propose a way to braid MFs without moving vortices. The only operation required in the present scheme is to turn on and off local gate voltages, which liberates a MF from its original host vortex and transports it along the prepared track. We solve the time-dependent Bogoliubov-de Gennes equation numerically, and confirm that the MFs are protected provided the switching of gate voltages for exchanging MFs are adiabatic, which takes only several nano seconds given reasonable material parameters. By monitoring the time evolution of MF wave-functions, we show that non-Abelian statistics is achieved.

Hydraulic retention time optimization achieved unexpectedly high nitrogen removal rate in pilot-scale anaerobic/aerobic/anoxic system for low-strength municipal wastewater treatment.

Applications of post-denitrification processes are subjected to low reaction rates caused by a lack of carbon resources. To offer a solution for reaction rate promotion, this research found a pilot-scale anaerobic/aerobic/anoxic bioreactor treating 55-120 m3/d low-strength municipal wastewater for 273 days. A short hydraulic retention time (HRT, 5-6 h) and a high nitrogen removal rate (63.2 ± 9.3 g-N/m3·d) were achieved using HRT optimization. The effluent total nitrogen concentration was maintained at 5.8 ± 1.4 mg/L while operating at a high nitrogen loading rate of 86.2 ± 12.8 g-N/m3·d. The short aeration (1.25-1.5 h) minimized the Glycogen loss. The endogenous denitrification rate increased to above 1.0 mg/(g-VSS·h). The functional genus Ca. Competibacter enriched to 2.3 %, guaranteeing the efficient post-denitrification process. Dechloromonas rose to 1.1 %, aiding in the synchronous phosphorus removal. These findings offered fresh insights into AOA processes to achieve energy/cost-saving wastewater treatment.

High-pressure synthesis, crystal structure, and properties of In2NiMnO6 with antiferromagnetic order and field-induced phase transition.

In2NiMnO6, a new compound extending the family of double rare-earth perovskites R2NiMnO6 (R = rare earth, Y) to smaller R ions, was prepared using a high-pressure and high-temperature technique (6 GPa and 1600 K). Its crystal structure was investigated by synchrotron X-ray powder diffraction at room temperature: space group P2(1)/n (No. 14, cell choice 2), Z = 2, a = 5.13520(1) Å, b = 5.33728(1) Å, c = 7.54559(4) Å, and ß = 90.1343(1)°. A significant degree of ordering of Mn(4+) and Ni(2+) ions was observed. The dc and ac magnetization and specific heat measurements showed that In2NiMnO6 is an antiferromagnet with a Néel temperature TN of 26 K. Its antiferromagnetism puts it apart from other members of the R2NiMnO6 family where a ferromagnetic ground state was observed, which is attributed to the superexchange interaction between Mn(4+) and Ni(2+) ions according to the Kanamori-Goodenough rules. A field-induced phase transition to a ferromagnetic state was observed from 18 kOe at 5 K, indicating that In2NiMnO6 is close to the antiferromagnetic-ferromagnetic transition boundary. First-principles calculations allowed us to explain its antiferromagnetism and the field-induced phase transition and predict the E* type antiferromagnetic ground state.

Is re-Rex shunt a better choice for patients with failed Rex shunt?

Purpose: To review our single-center surgical outcomes of redo operations after failed Rex shunt procedures. Methods: From September 2017 to October 2021, a total of 20 patients (11 males, 9 females; median age: 8.6 years) with Rex shunt occlusions were admitted to our hospital. Two of these patients were previously operated on in our hospital, and the remaining 18 were from other centers. All patients underwent repeat operations after detailed preoperative evaluations. Results: Preoperative wedged hepatic vein portography (WHVP) was conducted for 18 patients. Thirteen patients exhibited well-developed Rex recessus and intrahepatic portal vein during WHPV examination, consistent with the intraoperative exploration results. Fifteen patients (75%, 15/20) underwent redo-Rex shunt, four underwent Warren shunt and one underwent devascularization surgery. During the redo-Rex shunt operations, the left internal jugular veins (IJV) were used as bypass grafts in 11 patients; the intra-abdominal veins were used in 4 patients. The patients were followed up for 12-59 months (mean, 24.8 months). After redo Rex shunts, the grafts were patent in 14 patients (93.3%, 14/15), but 1 graft had thrombosis (6.7%, 1/15). Three patients suffered from postoperative anastomotic stenosis, and all of the stenosis was relieved with balloon dilatations. After re-Rex shunts, esophageal varices and spleen size were substantially reduced, and the platelet count significantly increased. Postoperative graft thrombosis was found in 1 patient after Warren shunt (1/4, 25%), and there was no graft stenosis. Compared with Warren surgery, patients who underwent re-Rex shunt had a significantly higher rate of platelet increase. Conclusions: Redo-rex shunts can be finished in most patients with failed Rex shunts. Re-Rex shunt is a preferred surgical choice after a failed Rex shunt when a good bypass graft is available, and the surgical success rate can reach more than 90%. A suitable bypass graft is essential for a successful redo Rex shunt. Preoperative WHVP is recommended for the design of a redo surgical plan preoperatively.

Laparoscopic Surgery for Focal-Form Congenital Hyperinsulinism Located in Pancreatic Head.

Background and Aims: Congenital hyperinsulinism of infancy (CHI) is a rare condition that may cause irreversible severe neurological damage in infants. For children in whom medical management fails, partial or near-total pancreatectomy is then required according to the type of lesion. Currently, open surgery of near-total pancreatic head resection is a mature technique for the treatment of focal-form CHI located in the head of the pancreas, but a minimally invasive laparoscopic procedure has not been reported yet. The aim of this study was to verify the feasibility, safety, and efficacy of laparoscopic pancreatic head resection and Roux-en-Y pancreaticojejunostomy for focal-form CHI. Methods: Two infants with persistent hypoglycemia and increased insulin levels were diagnosed with CHI and underwent laparoscopic near-total pancreatic head resection due to a suboptimal response to medical therapy and the likelihood of focal disease amenable to surgery. Clinical records, operative findings, and postoperative follow-up were collected and analyzed. Results: The operative duration was 300-330 min, and the intraoperative blood loss was minimal. The duration of postoperative abdominal drainage was 4-5 days. Neither intra- nor postoperative abdominal complications occurred. Oral feeding was resumed 3-4 days after the operation, and the blood glucose level was gradually stabilized to within the normal range. Normal blood glucose was observed in both patients over a follow-up period of 3-6 months. Conclusions: Laparoscopic pancreatic head resection and Roux-en-Y pancreaticojejunostomy can be considered a safe and effective procedure with minimal morbidity and excellent outcomes for the treatment of focal CHI in the head of the pancreas.

Shubnikov-de Haas oscillations and nontrivial topological states in Weyl semimetal candidate SmAlSi.

The RAlX (R = Light rare earth; X = Ge, Si) compounds, as a family of magnetic Weyl semimetal, have recently attracted growing attention due to the tunability of Weyl nodes and its interactions with diverse magnetism by rare-earth atoms. Here, we report the magnetotransport evidence and electronic structure calculations on nontrivial band topology of SmAlSi, a new member of this family. At low temperatures, SmAlSi exhibits large non-saturated magnetoresistance (MR) (as large as ∼5500% at 2 K and 48 T) and distinct Shubnikov-de Haas (SdH) oscillations. The field dependent MRs at 2 K deviate from the semiclassical (µ0H)2variation but follow the power-law relation MR∝(µ0H)mwith a crossover fromm∼ 1.52 at low fields (µ0H< 15 T) tom∼ 1 under high fields (µ0H> 18 T), which is attributed to the existence of Weyl points and electron-hole compensated characteristics with high mobility. From the analysis of SdH oscillations, two fundamental frequencies originating from the Fermi surface pockets with non-trivialπBerry phases and small cyclotron mass can be identified, this feature is supported by the calculated electronic band structures with two Weyl pockets near the Fermi level. Our study establishes SmAlSi as a paradigm for researching the novel topological states of RAlX family.

Zitterbewegung in the honeycomb photonic lattice.

The propagation of a wave packet in a honeycomb photonic lattice has been studied using the time-dependent wave packet dynamics. It is found that the wave packet, superposed from the positive and negative energy modes at the vicinity of the two inequivalent Dirac points, can transform into a double-ring structure, which is caused by the interference between the two positive and negative energy modes around the Dirac points and is closely related to the Zitterbewegung (ZB). Also, a possible way to detect the ZB effect is proposed in the honeycomb photonic lattice.

Enhanced photocatalytic hydrogen production of MoS2 sheet/carbon nanofiber using rapid electron transport of Mo6+ and carbon nanofiber.

Normal MoS2 exhibits a low photocatalytic performance for H2 production owing to the deficiency of the active sites and the poor electrical conductance. In this work, MoS2 anchored on the surface of the carbon nanofibers was designed to enhance the activity of the exposed edge and the electrical conductivity at the same time. The oxidation of the surface Mo atoms increases the activity of the exposed edge of the MoS2. The introduction of carbon nanofibers facilitates the effective transportation of the electron-hole pairs by enhancing the electrical conductivity. As a result, the introduction of carbon nanofibers and Mo6+ can facilitate the electron-hole pair separation to enhance the photocatalytic hydrogen evolution reaction (HER) performance (to eight fold more than normal MoS2).

Complete biodegradation of di-n-butyl phthalate (DBP) by a novel Pseudomonas sp. YJB6.

Phthalate acid esters (PAEs) are environmentally ubiquitous and have aroused a worldwide concern due to their threats to environment and human health. Di-n-butyl phthalate (DBP) is one of the most frequently observed PAEs in the environment. In this study, a novel bacterium identified as Pseudomonas sp. YJB6 that isolated from PAEs-contaminated soil was determined to have strong DBP-degrading activity. A complete degradation of DBP in 200 mg/L was achieved within 3 days when YJB6 was cultivated at 31.4 °C with an initial inoculation size of 0.6 (OD600) in basic mineral salts liquid medium (MSM), pH 7.6. The degradation curves of DBP (50-2000 mg/L) fitted well the first-order kinetics model, with a half-life (t1/2) ranging from 0.86 to 1.88 d. The main degradation intermediates were identified as butyl-ethyl phthalate (BEP), mono-butyl phthalate (MBP), phthalic acid (PA) and benzoic acid (BA), indicating a new complex and complete biodegradation pathway presented by YJB6. DBP might be metabolized through de-esterification, ß-oxidation, and hydrolysis, followed by entering the Krebs cycle of YJB6 as a final step. Strain YJB6 was successfully immobilized with sodium alginate (SA), polyvinyl alcohol (PVA), and SA-PVA. The immobilization significantly improved the stability and adaptability of the cells thus resulting in high volumetric DBP-degrading rates compared to that of the freely suspended cells. In addition, these immobilized cells can be reused for many cycles with well conserved in DBP-degrading activity. The ideal DBP degrading ability of the free and immobilized YJB6 cells suggests that strain YJB6, especially the SA-PVA+ YJB6 promises great potential to remove hazardous PAEs.

2D atomic crystal molecular superlattices by soft plasma intercalation.

Two-dimensional (2D) atomic crystal superlattices integrate diverse 2D layered materials enabling adjustable electronic and optical properties. However, tunability of the interlayer gap and interactions remain challenging. Here we report a solution based on soft oxygen plasma intercalation. 2D atomic crystal molecular superlattices (ACMSs) are produced by intercalating O2+ ions into the interlayer space using the plasma electric field. Stable molecular oxygen layer is formed by van der Waals interactions with adjacent transition metal dichalcogenide (TMD) monolayers. The resulting interlayer gap expansion can effectively isolate TMD monolayers and impart exotic properties to homo-(MoS2[O2]x) and hetero-(MoS2[O2]x/WS2[O2]x) stacked ACMSs beyond typical capacities of monolayer TMDs, such as 100 times stronger photoluminescence and 100 times higher photocurrent. Our potentially universal approach to tune interlayer stacking and interactions in 2D ACMSs may lead to exotic superlattice properties intrinsic to monolayer materials such as direct bandgap pursued for future optoelectronics.

π-Extended C2-Symmetric Double NBN-Heterohelicenes with Exceptional Luminescent Properties.

Two novel B,N-embedded double heterohelicenes, Ph-NBNDH and Naph-NBNDH, with intensively twisted quasi-C2 symmetrical structures are synthesized for the first time via a highly regioselective intramolecular Scholl reaction. The π-extended skeletons render them with exceptional physical properties, such as the highest fluorescence quantum yields up to 0.83 among multiple helicenes. Moreover, the isolated (M,M)- and (P,P)-enantiomers of Naph-NBNDH deliver intense circularly polarized luminescence. As the emitting layer, Ph-NBNDH exhibits strong electroluminescence at high working voltage.

Improving yield and quality of vegetable grown in PAEs-contaminated soils by using novel bioorganic fertilizer.

Phthalate acid esters (PAEs) are ubiquitous pollutants in agricultural soils. Application of bioorganic fertilizer (BOF) containing beneficial microbes represents a promising approach to improve the yield and quality of crops grown in contaminated soils. In the present study, a novel multifunctional bioorganic fertilizer N-BOF was developed by using compost of sewage sludge and agricultural waste and inoculating with PAEs-degrading B. megaterium YJB3 and phosphate solubilizing B. megaterium YLYP1. Its feasibility of improving the yield and quality of vegetable grown in PAEs (including DBP and DEHP) contaminated soil was evaluated by pot experiments. The N-BOF could effectively promote plant growth, with biomass increasing by 4-66.9% and 19-110% compared to chemical (CF) and no fertilizer (CK), respectively. The concentrations of DBP and DEHP in shoots of chemically fertilised vegetable ranged 1.23-3.12 mg/kg (dry weight, DW) and 1.63-3.89 mg/kg (DW), respectively. Their concentrations were significantly decreased (p < 0.05) when N-BOF was applied (1%, 2%, 5% amendment), especially at higher application rate ranging 0.11-0.3 mg/kg (DW) and 0.16-0.32 mg/kg (DW), respectively. Meanwhile, vegetable quality attributes were also significantly improved when 2% N-BOF was applied, with increase in the contents of vitamin C, vitamin B1, total protein, and starch, and decrease in the contents of nitrite and nitrate. In this case, the human health risk from consumption of the vegetable grown in PAEs-contaminated soil could be significantly reduced. Thus, our study is expected to provide an efficient way of high-value utilization of organic substrates by producing low-cost but high quality N-BOF. Future studies on the effects of N-BOF in terms of fertilizer regimes on yield and quality of the vegetable are needed, and further field studies for assessing the long-term efficacy and reliability of this promising N-BOF are also warranted.

Laparoscopic Management of Choledochal Cysts Associated with Aberrant Hepatic Ducts.

Introduction and objectives: This study assessed the diagnostic protocol and the outcomes of laparoscopic aberrant hepatic duct (AHD) reconstruction in choledochal cyst (CC) surgery. Methods: From January 2010 to January 2018, 275 laparoscopic CC excisions were conducted in our hospital. Seven patients of CC with associated AHD were recorded. AHDs that drained into the cystic duct were anastomosed to the Roux-en-Y loop. Clinical data of these 7 patients were retrospectively analyzed. Results: AHD is classified into four types according to the literature. The type where AHD drains into the cystic duct is the most commonly encountered one. The incidence of this type was 2.5% (7/275) in our series. Preoperative examination included magnetic resonance cholangiopancreatography (MRCP) (5 patients) and computed tomography (CT) scan (2 patients). Suspected AHD was diagnosed preoperatively in 4 out of the 5 patients who underwent MRCP. For the 2 patients who underwent CT scan only, AHD was not detected preoperatively. AHD was verified intraoperatively for all the 4 patients who had suspected diagnosis. Among them, AHD was well preserved in 3 patients, but damaged at exploration in the remaining 1. For the remaining 3 patients without preoperative AHD diagnosis, bile leakage was detected intraoperatively. Ductoplasty of the AHD with common hepatic duct was performed in 3 patients, and AHD was incorporated into the Roux-en-Y jejunal loop separately in 4 patients. Laparoscopic surgical procedures were completed in 6 of the 7 patients in this study, while 1 patient was converted into an open procedure. Postoperative recovery was uneventful in all patients. The duration of follow-up ranged from 6 months to 4 years (median 2 years) with no complication encountered. Conclusions: Routine preoperative MRCP examination of CC is recommended to detect variations of biliary tree. The laparoscopic approach is a feasible option in the experienced hands.

Two-dimensional semiconducting covalent organic frameworks via condensation at arylmethyl carbon atoms.

Construction of organic semiconducting materials with in-plane π-conjugated structures and robustness through carbon-carbon bond linkages, alternatively as organic graphene analogs, is extremely desired for powerfully optoelectrical conversion. However, the poor reversibility for sp2 carbon bond forming reactions makes them unavailable for building high crystalline well-defined organic structures through a self-healing process, such as covalent organic frameworks (COFs). Here we report a scalable solution-processing approach to synthesize a family of two-dimensional (2D) COFs with trans-disubstituted C = C linkages via condensation reaction at arylmethyl carbon atoms on the basis of 3,5-dicyano-2,4,6-trimethylpyridine and linear/trigonal aldehyde (i.e., 4,4″-diformyl-p-terphenyl, 4,4'-diformyl-1,1'-biphenyl, or 1,3,5-tris(4-formylphenyl)benzene) monomers. Such sp2 carbon-jointed-pyridinyl frameworks, featuring crystalline honeycomb-like structures with high surface areas, enable driving two half-reactions of water splitting separately under visible light irradiation, comparable to graphitic carbon nitride (g-C3N4) derivatives.