Bottom-Up Construction of Rhombic Lamellar CoNi-MOFs for the Electrochemical Sensing of H2S.

Lamellar metal-organic frameworks (MOFs) have attracted significant attention in the field of electrochemical sensing due to their abundant open active sites and specific electron conductivity. Herein, by employing a bottom-up synthesis strategy, rhombic lamellar heterometallic CoNi-MOFs with varying thicknesses are constructed. This is achieved by using 4-methylpyridine as a capping agent based on the (4,6)-linked Co2(azpy)2(bptc) (azpy = 4,4'-azopyridine, bptc = 3,3',5,5'-biphenyltetracarboxylic acid) structure with a fsc topology and by introducing Ni species simultaneously. To mitigate sulfur deposition on electrodes, the triple pulse amperometry (TPA) method is employed. Among the synthesized lamellar CoNi-MOFs, lamellar CoNi-MOF-3 with the minimum thickness exhibits an optimal electrochemical sensing performance toward hydrogen sulfide, with a sensitivity of 119.3 µA·mM-1·cm-2 in the linear range of 2-2000 µM. This study pioneers a new approach to the controlled construction and electrochemical activity modification of lamellar MOF materials.

Minor alkaloids from an aqueous extract of the hook-bearing stem of Uncaria rhynchophylla.

Seven new monoterpene alkaloids (1 - 7), along with 16 known analogues, were isolated from an aqueous decoction of the hook-bearing stems of Uncaria rhynchophylla (Gou-teng). Their structures were determined by spectroscopic data analysis, single crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are stereoisomers belonging to a novel type of pseudoindoxyl monoterpene alkaloids, 3 is the first monoterpene furoindole alkaloid from nature, and 4 - 7 are derivatives of the known monoterpene alkaloids featuring different structures.

Benzo[g]quinoxaline-Based Complexes [Ir(pbt)2(dppn)]Cl and [Ir(pt)2(dppn)]Cl: Modulation of Photo-Oxidation Activity and Light-Controlled Luminescence.

Based on benzo[i]dipyrido[3,2-a:2',3'-c]phenazine (dppn) with photo-oxidation activity, complexes [Ir(pbt)2(dppn)]Cl (1) and [Ir(pt)2(dppn)]Cl (2) have been synthesized (pbtH = 2-phenylbenzothiazole, and ptH = 2-phenylthiazole), with two aims, including studying the influence of the cyclometalating ligands (pbt- in 1, pt- in 2) on the photo-oxidation activity of these complexes and exploring their photo-oxidation-induced luminescence. Both 1H nuclear magnetic resonance (NMR) and electrospray (ES) mass spectrometry indicate that the benzo[g]quinoxaline moiety in complex 1 can be oxidized at room temperature upon irradiation with 415 nm light. Thus, this complex in CH2Cl2 shows photo-oxidation-induced turn-on yellow luminescence. In contrast, complex 2 reveals significant structural decomposition during the process of photo-oxidation due to incorporating a cyclometalating ligand pt- instead of pbt- in complex 1. In this paper, we report the photo-oxidation behaviors and the related luminescence modulation in 1 and 2 and discuss the relationship between structure and photo-oxidation activity in these complexes.

Diverse neolignans and lignans from an aqueous extract of the Angelica sinensis root head.

Neolignans and lignans with diverse new chemical structures, including eleven pairs of separated chiral enantiomers [(+)-/(-)-1-(+)-/(-)-5, (+)-/(-)-8, (+)-/(-)-10, and (+)-/(-)-12-(+)-/(-)-15], two achiral compounds (6 and 9), and an unseparated racemate [(±)-11], together with a new natural product (7) and 21 known derivatives, were isolated from an aqueous extract of the Angelica sinensis root head (guitou). Among the chiral isolates, (+)-/(-)-13 and (+)-/(-)-15 were scalemic pairs with enantiomeric ratios of around 3:1 and 1.5:1, respectively, while others were enantiomeric equivalent pairs. This indicates that the diverse neolignans in A. sinensis are biosynthesized via different pathways with varying degrees of stereo-controlled manners.

Highly Robust Microporous Metal-Organic Frameworks for Efficient Ethylene Purification under Dry and Humid Conditions.

Two C2 H6 -selective metal-organic framework (MOF) adsorbents with ultrahigh stability, high surface areas, and suitable pore size have been designed and synthesized for one-step separation of ethane/ethylene (C2 H6 /C2 H4 ) under humid conditions to produce polymer-grade pure C2 H4 . Experimental results reveal that these two MOFs not only adsorb a high amount of C2 H6 but also display good C2 H6 /C2 H4 selectivity verified by fixed bed column breakthrough experiments. Most importantly, the good water stability and hydrophobic pore environments make these two MOFs capable of efficiently separating C2 H6 /C2 H4 under humid conditions, exhibiting the benchmark performance among all reported adsorbents for separation of C2 H6 /C2 H4 under humid conditions. Moreover, the affinity sites and their static adsorption energies were successfully revealed by single crystal data and computation studies. Adsorbents described in this work can be used to address major chemical industrial challenges.

Sulfonated alkaloids from an aqueous extract of Isatis indigotica roots.

Eleven new sulfonated alkaloids (1 - 11) having diverse structures were isolated from an aqueous extract of the Isatis indigotica root (ban lan gen). Their structures were determined by spectroscopic data analysis, chemical method, and theoretical calculation, of which (-)-4 was proved by single crystal X-ray diffraction.

Minor monoterpene derivatives from an aqueous extract of the hook-bearing stem of Uncaria rhynchophylla.

Seven new minor monoterpene derivatives (1-7), together with six known analogues, were isolated from an aqueous decoction of the hook-bearing stems of Uncaria rhynchophylla (Gou-teng). Their structures were determined by spectroscopic data analysis and electronic circular dichroism (ECD) calculations, of which 1 was confirmed by single crystal X-ray diffraction.

Lignans and a neolignan from an aqueous extract of Isatis indigotica roots.

Four new lignans (1-4) and one new neolignan (5), along with two known lignan derivatives (6 and 7), were isolated from an aqueous extract of the Isatis indigotica root (ban lan gen). Their structures were determined by spectroscopic data analysis, chemical method, and theoretical calculation, for which 1 was proved by single-crystal X-ray diffraction. Compound 2 exhibited antiviral activity against influenza virus A/Hanfang/359/95 (H3N2) with an IC50 value of 11.1 µM and a selective index (SI) > 9, while 1 and 5 are the first examples of sulfonated lignan and neolignan from nature.

[Spectral characteristics of sesquiterpene pyridine alkaloids from Tripterygium plants].

Sesquiterpene pyridine alkaloids are important components in Tripterygium plants, possessing a wide range of pharmacological activities, such as anti-inflammation immunosuppression, anti-tumor, anti-virus, and deinsectization, and are of great research value. They are composed of highly oxidized dihydro-ß-furansquiterpene and pyridine dicarboxylic acid through ester bonds. According to the structural characteristics of pyridine dicarboxylic acid fragments, they can be divided into various structural subtypes. Up to now, more than 110 sesquiterpene pyridine alkaloids have been isolated and identified from Tripterygium plants. This study reviewed the structural features and spectral(i.e., UV, IR, MS, and NMR) characteristics of sesquiterpene pyridine alkaloids and summarized the structural elucidation process in detail to provide references for their further research and development.

Surface Modification of Nano-Cu2 O for Controlling CO2 Electrochemical Reduction to Ethylene and Syngas.

In the surroundings of carbon neutrality, nano-Cu2 O is considered a promising catalyst for the electrochemical CO2 reduction reaction (ECO2 RR), whose improvements in product selectivity still require considerable efforts. Here, we present an efficient strategy for controlling the ECO2 RR product by modifying the surface of nano-Cu2 O, i.e., by controlling the exposed facets via a reductant-controlled method to achieve the highest C2 H4 selectivity (Faradic efficiency=74.1 %) for Cu2 O-based catalysts in neutral electrolytes, and introducing a well-suited metal-organic framework (MOF) coating on the surface of nano-Cu2 O to obtain syngas completely with an appropriate H2 :CO ratio. Detailed mechanism and key intermediate have been illustrated by DFT calculations. Our systematic strategy is expected to control the ECO2 RR product, improve the selectivity, and provide a reliable method for CO2 management and the green production of important carbon resources.

Au⋠⋠⋠H-C Interactions Support a Robust Thermally Activated Delayed Fluorescence (TADF) Gold(I) Complex for OLEDs with Little Efficiency Roll-Off and Good Stability.

The practical use of luminescent mononuclear gold(I) complexes as optoelectronic materials has been limited by their inferior stability. Herein we demonstrate a strategy to improve the stability of gold(I) complexes which display thermally activated delayed fluorescence (TADF). A highly rigid and groove-like σ-donating aryl ligand has been used to form dual Au⋅⋅⋅H-C hydrogen bonds. The secondary metal-ligand interactions have been authenticated by single-crystal structure, NMR spectroscopy and theoretical simulations. The TADF AuI complex exhibits appealing emission properties (photoluminescence quantum yield=76 %; delayed fluorescence lifetime=1.2 µs) and much improved thermal and photo-stability. Vacuum-deposited organic light-emitting diodes (OLEDs) show promising electroluminescence with a maximum external quantum efficiency (EQE) over 23 % and negligible efficiency roll-off even at 10 000 cd m-2 . An estimated LT50 longer than 77 000 h with initial luminance of 100 cd m-2 reveals good operational stability. This work suggests a way for design of stable luminescent gold(I) complexes.

Fabrication of Moisture-Responsive Crystalline Smart Materials for Water Harvesting and Electricity Transduction.

It is of profound significance with regard to the global energy crisis to develop new techniques and materials that can convert the chemical potential of water into other forms of energy, especially electricity. To address this challenge, we built a new type of energy transduction pathway (humidity gradients → mechanical work → electrical power) using moisture-responsive crystalline materials as the media for energy transduction. Single-crystal data revealed that a flexible zeolitic pyrimidine framework material, ZPF-2-Co, could undergo a reversible structural transformation (ß to α phase) with a large unit cell change upon moisture stimulus. Dynamic water vapor sorption analysis showed a gate-opening effect with a steep uptake at as low as 10% relative humidity (RH). The scalable green synthesis approach and the fast water vapor adsorption-desorption kinetics made ZPF-2-Co an excellent sorbent to harvest water from arid air, as verified by real water-harvesting experiments. Furthermore, we created a gradient distribution strategy to fabricate polymer-hybridized mechanical actuators based on ZPF-2-Co that could perform reversible bending deformation upon a variation of the humidity gradient. This mechanical actuator showed remarkable durability and reusability. Finally, coupling the moisture-responsive actuator with a piezoelectric transducer further converted the mechanical work into electrical power. This work offers a new type of moisture-responsive smart material for energy transduction and provides an in-depth understanding of the responsive mechanism at the molecular level.

Divanillyl sulfone suppresses NLRP3 inflammasome activation via inducing mitophagy to ameliorate chronic neuropathic pain in mice.

BACKGROUND: Chronic neuropathic pain is a frequent sequel to peripheral nerve injury and maladaptive nervous system function. Divanillyl sulfone (DS), a novel structural derivative of 4,4'-dihydroxydibenzyl sulfoxide from a traditional Chinese medicine Gastrodia elata with anti-nociceptive effects, significantly alleviated neuropathic pain following intrathecal injection. Here, we aimed to investigate the underlying mechanisms of DS against neuropathic pain. METHODS: A chronic constrictive injury (CCI) mouse model of neuropathic pain induced by sciatic nerve ligation was performed to evaluate the effect of DS by measuring the limb withdrawal using Von Frey filament test. Immunofluorescence staining was used to assess the cell localizations and expressions of Iba-1, ASC, NLRP3, and ROS, the formation of autolysosome. The levels of NLRP3-related proteins (caspase-1, NLRP3, and IL-1ß), mitophagy-related proteins (LC3, Beclin-1, and p62), and apoptosis-related proteins (Bcl-XL and Bax) were detected by Western blotting. The apoptosis of BV-2 cell and caspase activity were evaluated by flow cytometry. RESULTS: DS significantly alleviated the neuropathic pain by increasing the mechanical withdrawal threshold and inhibiting the activation of NLRP3 in CCI-induced model mice. Our findings indicated that DS promoted the mitophagy by increasing the LC3II and Beclin 1 and decreasing the levels of p62 protein in BV-2 cell. This is accompanied by the inhibition of NLRP3 activation, which was shown as inhibited the expression of NLRP3 in lysates as well as the secretion of mature caspase-1 p10 and IL-1ß p17 in supernatants in cultured BV-2 microglia. In addition, DS could promote mitophagy-induced improvement of dysfunctional mitochondria by clearing intracellular ROS and restoring mitochondrial membrane potential. CONCLUSION: Together, our findings demonstrated that DS ameliorate chronic neuropathic pain in mice by suppressing NLRP3 inflammasome activation induced by mitophagy in microglia. DS may be a promising therapeutic agent for chronic neuropathic pain.

Highly Efficient Thermally Activated Delayed Fluorescence from Pyrazine-Fused Carbene Au(I) Emitters.

Metal-based thermally activated delayed fluorescence (TADF) is conceived to inherit the advantages of both phosphorescent metal complexes and purely organic TADF compounds for high-performance electroluminescence. Herein a panel of new TADF Au(I) emitters has been designed and synthesized by using carbazole and pyrazine-fused nitrogen-heterocyclic carbene (NHC) as the donor and acceptor ligands, respectively. Single-crystal X-ray structures show linear molecular shape and coplanar arrangement of the donor and acceptor with small dihedral angles of <6.5°. The coplanar orientation and appropriate separation of the HOMO and LUMO in this type of molecules favour the formation of charge-transfer excited state with appreciable oscillator strength. Together with a minor but essential heavy atom effect of Au ion, the complexes in doped films exhibit highly efficient (Φ∼0.9) and short-lived (<1 µs) green emissions via TADF. Computational studies on this class of emitters have been performed to decipher the key reverse intersystem crossing (RISC) pathway. In addition to a small energy splitting between the lowest singlet and triplet excited states (ΔEST ), the spin-orbit coupling (SOC) effect is found to be larger at a specific torsion angle between the donor and acceptor planes which favours the RISC process the most. This work provides an alternative molecular design to TADF Au(I) carbene emitters for OLED application.

Controlled Thermal Conversion Strategy to Provide Metal-Organic Framework-Supported Composite Catalysts.

Metal-organic framework (MOF)-supported metal/metal compound nanoparticles (NPs) have emerged as a new class of composite catalysts. However, huge challenges prevail in placing such NPs in the MOF pores because of the poor solubility of metal/metal oxides, limited availability of suitable precursors, metastable attribute of given metal ions, and lower thermal stability of MOFs compared to conventional porous materials. Based on the difference between the thermal stability of the precursor and MOFs, we successfully developed a controlled thermal conversion (CTC) method to load cobalt(II) oxide (CoO) NPs into the framework of MOF (MIL-101) to conveniently obtain a composite catalyst, CoO@MIL-101, which is a very rare example of pure CoO NP-loaded composite catalyst that shows excellent catalytic activity in the selective oxidation of benzyl alcohol. This CTC strategy opens up a pathway for impregnating MOF supports with specific NPs, which is further confirmed by preparing the first CuBr@MOF-type composite catalyst.

Construction of CuII Defects on CuCl Nanoparticles in Metal-Organic Frameworks toward Composite Catalysts with Superior Activity.

Metal-organic frameworks (MOFs) represent an ideal platform for the construction of highly active composite catalysts. However, loading metastable and/or multicomponent metal compounds into MOFs remains a synthetic bottleneck due to the great challenge of keeping the guest and matrix intact during the preparation of a composite. In this work, we develop a new impregnation reduction surface modification (IRSM) strategy to give a new composite catalyst CuCl@MIL-101(Cr), which is successfully postmodified by in situ construction of CuII defects on the surface of loaded CuCl inside MOF pores, leading to the new composite material CuII/CuI@MIL-101(Cr). The new dual-component composite catalyst exhibits a hierarchical structure and superior catalytic activity in C-C homocoupling of arylboronic acids under green conditions. This study presents a facile strategy for improving the catalytic activity by constructing defects on the surface of MOF-based catalysts as well as for forming multiple-component composite materials.

An analysis of clinical characteristics and postoperative complications in children craniopharyngioma.

OBJECTIVE: Children treated for craniopharyngioma (CP) experience significant morbidity. We aimed to investigate the clinical characteristics and postoperative complications of pediatric CP and to determine risk factors for complications to provide a theoretical basis for postoperative treatment. METHODS: In this retrospective analysis, we screened clinical data concerning children with CP who had undergone surgery at our hospital from December 2011 to June 2015. We statistically analyzed the relationship between age, sex, disease course, tumor location, extent of tumor resection, and neuroendocrine axis dysfunction. RESULTS: Of 240 patients (males, n = 144; females, n = 96; mean age, 8.33 ± 4.64 years), the main clinical presentations were headache (n = 151, 62.92%), vomiting (n = 84, 35%), vision changes (n = 101, 42.08%), polydipsia and polyuria (n = 47, 19.58%), and growth retardation (n = 42, 17.5%). Hypothalamic-pituitary dysfunction was the most common postoperative complication. There were 216 (90.00%) and 181 (75.42%) patients with pituitary-thyroid and pituitary-adrenal axis injuries, respectively. Being a prepubescent girl was a risk factor for impaired pituitary-thyroid and pituitary-adrenal axis function (P < 0.05). No correlation was found between sex (male), age, disease course, tumor location, extent of tumor resection, and impaired pituitary-thyroid and pituitary-adrenal axis function (P > 0.05). Pituitary-gonad axis injury was observed in 91 (37.92%) patients. Saddle and suprasellar region tumors were risk factors for impaired pituitary-gonad axis function (P < 0.05). No statistically significant correlation was found between sex, disease course, extent of resection, and impaired pituitary-gonad axis function (P > 0.05). CONCLUSIONS: Routine screening for complications during treatment is indicated for children with CP, to optimize the timing of interventions and reduce long-term morbidity.

Minor alkaloids from an aqueous extract of the hook-bearing stem of Uncaria rhynchophylla.

Seven new monoterpene alkaloids (1-7), along with 18 known analogues, were isolated from an aqueous decoction of the hook-bearing stems of Uncaria rhynchophylla (Gou-teng). Their structures were determined by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Compound 1 is the first monoterpene 22-norindoloquinolizidine alkaloid with a ketene unit, while 2 and 3 are unusual indoloquinolizidine alkaloids having an oxazinane ring.[Formula: see text].

Minor triterpenes from an aqueous extract of the hook-bearing stem of Uncaria rhynchophylla.

Six new triterpenes, uncarinic acids KP (1-6), along with 24 known analogues, were isolated as minor constituents of an aqueous decoction of the hook-bearing stems of Uncaria rhynchophylla (Gou-teng). By comprehensive spectroscopic data analysis, their structures were elucidated as derivatives of olean-12-en-28-oic acid and urs-12-en-28-oic acid with different oxidized forms at C-3, C-6, and/or C-23, respectively. Cell-based preliminary bioassay showed that the (E)-/(Z)-coumaroyloxy and (E)-/(Z)-feruloyloxy units at C-27 of olean-12-en-28-oic acid and urs-12-en-28-oic acid played roles in their bioactivities.[Formula: see text].

Denudatine-type diterpenoid alkaloids from an aqueous extract of the lateral root of Aconitum carmichaelii.

Five new denudatine-type diterpenoid alkaloids (1-5), along with the known analogue aconicarmine (6), were isolated from an aqueous decoction of the lateral roots of Aconitum carmichaelii (fu-zi). Their structures were determined by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Compound 5 is the first denudatine-type diterpenoid alcohol iminium alkaloid, which could be partially transformed into the aza acetal form in pyridine-d5. Compound 5 inhibited mice writhing in an acetic acid-induced writhing assay.