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Monolayer Bi2MoO6 nanosheets have been successfully prepared for the first time via a bottom-top approach with surfactant assistance, and show 8 times higher activity than bulk Bi2MoO6 for the selective oxidation of benzyl alcohol. Ultrafast charge separation and more acid–base active sites on the monolayer nanosheets are considered to be responsible for the robust photoactivity. [ABSTRACT FROM AUTHOR]

Here, we show for the first time that the photocatalytic activity of covalent triazine-based frameworks (CTFs) can be efficiently improved using a facile sulfur-doping approach. The sulfur-doped CTFs show superior photocatalytic activity and stability in hydrogen evolution from water under visible light irradiation over pristine CTFs and g-C3N4. The significantly improved catalytic efficiency was attributed to sulfur-doping in the frameworks, which results in enhanced adsorption of visible light, reduced recombination of free charge carriers, and rapid separation and transportation of photogenerated electron–holes. [ABSTRACT FROM AUTHOR]

Three ionic nitrogen-containing chelating ligands ( L1- L3) are synthesized readily through alkylation and quaternization of 2,2′-dipyridylamine. The charge distributions and natural bond orbital analyses of their cations are implemented by using density functional theory calculations. The catalytic performances of their water-soluble palladium complexes are evaluated preliminarily by using the Suzuki-Miyaura cross-coupling reaction, and high catalytic activities of aryl bromides and chlorides are achieved in neat water. The mercury drop test, poison experiments, and TEM analysis are used to demonstrate the formation of palladium nanoparticles (NPs) after the catalytic reaction. The effects of pendant ionic groups in L1- L3 on the catalytic activities and structures of the palladium NPs are disclosed. These NPs are stable in water for several weeks; they are stabilized by synergetic interactions between the chelating coordination of the 2,2′-dipyridylamino group to the surface of the palladium NPs and the electrostatic repulsion of the ionic groups in L1- L3. [ABSTRACT FROM AUTHOR]

The reaction of bis- or tris-chelating nitrogen-containing ligands (L1-L5) with CuI gave rise to five coordination complexes consisting of Cu2I2 dimeric units. L1 in complex 1 adopts a cis conformation and links Cu2I2 into a dinuclear structure. L2 and L3 in complexes 2 and 3 exhibit a trans conformation, and the alternative linkage of L2 or L3 and Cu2I2 results in the formation of a 1D chain. In complex 4, two pyrazolyl-pyridine units of L4 at the same side of the central phenyl ring are connected to Cu2I2 forming a tetranuclear macrocycle, and the third pyrazolyl-pyridine unit at the other side of the central phenyl ring further links the macrocycle into a 1D chain. L5 bridges Cu2I2 in a cis conformation forming a tetranuclear complex, which is very different from 1 owing to the difference of the electronic property between pyrazolyl and triazolyl rings. The coordination nitrogen atoms in two pairs of ortho-positioned nitrogen-containing chelating rings in L1 and L5 are directed toward opposite and the same directions, respectively. Complexes 1- 4 containing pyrazolyl-pyridine units showed luminescence whereas no clear emission was observed in complex 5 containing triazolyl-pyridine units, despite the fact that they were investigated under the same conditions. The application of complexes 1- 5 in the copper(I)-catalyzed Ullmann cross-coupling reaction and azide-alkyne cycloaddition reaction was preliminarily evaluated. [ABSTRACT FROM AUTHOR]

An ammonium-functionalized water-soluble bidentate nitrogen-containing ligand (3) and its palladium chelating complex (4) have been easily prepared from the commercial available starting materials in high overall yields. The charge distributions and molecular orbital analyses of 3, 4and non-ionic hydrophobic analogue (2a) based on the optimized structures were implemented. The crystal structure of 4has been established by single-crystal X-ray diffraction. The water-soluble palladium complex was a much more effective catalyst than 2ain palladium-catalyzed Suzuki–Miyaura cross-coupling reaction in air and pure water. High catalytic activity of aryl chlorides and aryl bromides was observed. The mercury drop test, poison experiments and TEM analysis of the catalytic solution showed Pd(0) were involved in catalysis. The palladium nanoparticles of 3.0 ± 0.6 nm were formed after the catalytic reaction, they were stabilized by synergetic effect of coordination and electrostatic interactions from the ammonium-functionalized chelating ligand. No precipitate was observed when the aqueous nanoparticles were stored in air for months. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor about SARS infection among health care workers in Beijing, China.

Supramolecular systems consisting of covalent organic frameworks (COFs) and Ni complex are designed for robust photocatalytic reduction of CO2. Multiple heteroatom‐hydrogen bonding between the COF and Ni complex is identified to play a decisive role in the photoexcited electron transfer across the liquid‐solid interface. The diminution of steric groups on COF or metal complex can optimize catalytic performance, which is more attributable to the enhanced hydrogen‐bond interaction rather than their intrinsic activity. The photosystem with relatively strong strength of hydrogen bonds exhibits remarkable photocatalytic CO2‐to‐CO conversion, far superior to photosystems with supported atomic Ni or metal complex alone in the absence of hydrogen‐bond effect. Such heteroatom‐hydrogen bonds bridging electron transport pathway confers supramolecular system with high photocatalytic performance, providing an avenue to rationally design efficient and steadily available photosystems. [ABSTRACT FROM AUTHOR]

Supramolecular systems consisting of covalent organic frameworks (COFs) and Ni complex are designed for robust photocatalytic reduction of CO2. Multiple heteroatom‐hydrogen bonding between the COF and Ni complex is identified to play a decisive role in the photoexcited electron transfer across the liquid‐solid interface. The diminution of steric groups on COF or metal complex can optimize catalytic performance, which is more attributable to the enhanced hydrogen‐bond interaction rather than their intrinsic activity. The photosystem with relatively strong strength of hydrogen bonds exhibits remarkable photocatalytic CO2‐to‐CO conversion, far superior to photosystems with supported atomic Ni or metal complex alone in the absence of hydrogen‐bond effect. Such heteroatom‐hydrogen bonds bridging electron transport pathway confers supramolecular system with high photocatalytic performance, providing an avenue to rationally design efficient and steadily available photosystems. [ABSTRACT FROM AUTHOR]

The design of photocatalytic supramolecular systems composing of semiconductors and molecular metal complexes for CO 2 reduction has attracted increasing attention. The supramolecular system combines the structural merits of semiconductors and metal complexes, where the semiconductor harvests light and undertakes the oxidative site, while the metal complex provides activity for CO 2 reduction. The intermolecular charge transfer plays crucial role in ensuring photocatalytic performance. Here, we review the progress of photocatalytic supramolecular systems in reduction of CO 2 and highlight the interfacial charge transfer pathways, as well as their state-of-the-art characterization methods. The remaining challenges and prospects for further design of supramolecular photocatalysts are also presented., (© 2024 Wiley-VCH GmbH.)

Facile fabrication of nanocatalysts consisting of metal nanoparticles (NPs) anchored on a functional support is highly desirable, yet remains challenging. Covalent organic frameworks (COFs) provide an emerging materials platform for structural control and functional design. Here, a facile one-pot in situ reduction approach is demonstrated for the encapsulation of small Pd NPs into the shell of COF-derived hollow polyamine spheres (Pd@H-PPA). In the one-pot synthetic process, the nucleation and growth of Pd NPs in the cavities of the porous shell take place simultaneously with the reduction of imine linkages to secondary amine groups. Pd@H-PPA shows a significantly enhanced catalytic activity and recyclability in the tandem dehydrogenation of ammonia borane and selective hydrogenation of nitroarenes through an adsorption-activation-reaction mechanism. The strong interactions of the secondary amine linkage with borane and nitroarene molecules afford a positive synergy to promote the catalytic reaction. Moreover, the hierarchical structure of Pd@H-PPA allows the accessibility of active Pd NPs to reactants., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photocatalytic reduction of CO 2 into energy-rich carbon compounds has attracted increasing attention. However, it is still a challenge to selectively and effectively convert CO 2 to a desirable reaction product. Herein, we report a design of a synergistic photocatalyst for selective reduction of CO 2 to CO by using a covalent organic framework bearing single Ni sites (Ni-TpBpy), in which electrons transfer from photosensitizer to Ni sites for CO production by the activated CO 2 reduction under visible-light irradiation. Ni-TpBpy exhibits an excellent activity, giving a 4057 μmol g -1 of CO in a 5 h reaction with a 96% selectivity over H 2 evolution. More importantly, when the CO 2 partial pressure was reduced to 0.1 atm, 76% selectivity for CO production is still obtained. Theoretical calculations and experimental results suggest that the promising catalytic activity and selectivity are ascribed to synergistic effects of single Ni catalytic sites and TpBpy, in which the TpBpy not only serves as a host for CO 2 molecules and Ni catalytic sites but also facilitates the activation of CO 2 and inhibits the competitive H 2 evolution.

The synthesis of five-membered cyclic carbonates via catalytic cycloaddition reaction of CO 2 with epoxides is considered to be an effective technology for alleviation of the energy crisis and global warming. Various commercial organic bases and ionic salts were used as catalysts, while the relationship of catalytic activity and compound structure has been seldom explored. Herein, a facilely obtained binary catalytic system based on triethylamine/NBu 4 Br was developed for CO 2 activation and chemical fixation. The highly efficient catalytic system showed outstanding conversion and above 99% selectivity under metal-free mild reaction conditions (100 °C, 1 atm) in one hour. The detailed process of CO 2 activation and chemical fixation was investigated at the molecular level by a series of experiments and theoretical calculation, which provided a mode for the design and synthesis of a highly efficient catalytic system for conversion of CO 2 under mild conditions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Objective: To carry out genetic testing for a family affected with distal hereditary motor neuronopathy V (dHMN V)., Methods: Potential mutations of the GARS and BSCL2 genes were analyzed with PCR and Sanger sequencing. Suspected mutation was verified among unaffected members of the family and 100 healthy controls. Prenatal diagnosis was provided based on the above results., Results: Sequencing analysis has identified a heterozygous c.269C>T (p.S90L) mutation in the BSCL2 gene, which resulted in replacement of Serine (TCG) to Leucine (TTG). The same mutation was found in all other 3 patients from the pedigree but not among unaffected members or the 100 healthy controls. By prenatal diagnosis, the fetus did not carry the above mutation., Conclusion: Pathogenic mutation of BSCL2 gene probably underlies the dHMN V in this pedigree, which enabled prenatal diagnosis for the proband.

MoS 2 quantum dots (QDs)-modified covalent triazine-based framework (MoS 2 /CTF) composites are synthesized through an in situ photodeposition method. MoS 2 QDs are well distributed and stabilized on the layers of CTFs by coordination of the frameworks to MoS 2 . The QDs-sheet interactions between MoS 2 and CTFs facilitate interfacial charge transfer and separation. As a consequence, the composites exhibit outstanding photocatalytic activity and stability for hydrogen evolution under visible light irradiation (λ≥420 nm), that exceed those over pristine CTFs and MoS 2 -modified g-C 3 N 4 (MoS 2 /g-C 3 N 4 ) composite, making them promising materials for solar energy conversion., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Monolayer Bi 2 MoO 6 nanosheets have been successfully prepared for the first time via a bottom-top approach with surfactant assistance, and show 8 times higher activity than bulk Bi 2 MoO 6 for the selective oxidation of benzyl alcohol. Ultrafast charge separation and more acid-base active sites on the monolayer nanosheets are considered to be responsible for the robust photoactivity.

Two urea-based porous organic frameworks, UOF-1 and UOF-2, were synthesized through a urea-forming condensation of 1,3,5-benzenetriisocyanate with 1,4-diaminobenzene and benzidine, respectively. UOF-1 and UOF-2 possess good hydrophilic properties and high scavenging ability for palladium. Their palladium polymers, PdII/UOF-1 and PdII/UOF-2, exhibit high catalytic activity and selectivity for Suzuki–Miyaura cross-coupling reactions and selective reduction of nitroarenes in water. The catalytic reactions can be efficiently performed at room temperature. Palladium nanoparticles with narrow size distribution were formed after the catalytic reaction and were well dispersed in UOF-1 and UOF-2. XPS analysis confirmed the coordination of the urea oxygen atom with palladium. SEM and TEM images showed that the original network morphology of UOF-1 and UOF-2 was maintained after palladium loading and catalytic reactions.

The reaction of bis- or tris-chelating nitrogen-containing ligands (L1-L5) with CuI gave rise to five coordination complexes consisting of Cu 2 I 2 dimeric units. L1 in complex 1 adopts a cis conformation and links Cu 2 I 2 into a dinuclear structure. L2 and L3 in complexes 2 and 3 exhibit a trans conformation, and the alternative linkage of L2 or L3 and Cu 2 I 2 results in the formation of a 1D chain. In complex 4, two pyrazolyl-pyridine units of L4 at the same side of the central phenyl ring are connected to Cu 2 I 2 forming a tetranuclear macrocycle, and the third pyrazolyl-pyridine unit at the other side of the central phenyl ring further links the macrocycle into a 1D chain. L5 bridges Cu 2 I 2 in a cis conformation forming a tetranuclear complex, which is very different from 1 owing to the difference of the electronic property between pyrazolyl and triazolyl rings. The coordination nitrogen atoms in two pairs of ortho-positioned nitrogen-containing chelating rings in L1 and L5 are directed toward opposite and the same directions, respectively. Complexes 1-4 containing pyrazolyl-pyridine units showed luminescence whereas no clear emission was observed in complex 5 containing triazolyl-pyridine units, despite the fact that they were investigated under the same conditions. The application of complexes 1-5 in the copper(I)-catalyzed Ullmann cross-coupling reaction and azide-alkyne cycloaddition reaction was preliminarily evaluated., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of click ionic salts 4 a-4 n was prepared through click reaction of organic azides with alkyne-functionalized imidazolium or 2-methylimidazolium salts, followed by metathesis with lithium bis(trifluoromethanesulfonyl)amide or potassium hexafluorophosphate. All salts were characterized by IR, NMR, TGA, and DSC, and most of them can be classified as ionic liquids. Their steric and electronic properties can be easily tuned and modified through variation of the aromatic or aliphatic substituents at the imidazolium and/or triazolyl rings. The effect of anions and substituents at the two rings on the physicochemical properties was investigated. The charge and orbital distributions based on the optimized structures of cations in the salts were calculated. Reaction of 4 a with PdCl(2) produced mononuclear click complex 4 a-Pd, the structure of which was confirmed by single-crystal X-ray diffraction analysis. Suzuki-Miyaura cross-coupling shows good catalytic stability and high recyclability in the presence of PdCl(2) in 4 a. TEM and XPS analyses show formation of palladium nanoparticles after the reaction. The palladium NPs in 4 a are immobilized by the synergetic effect of coordination and electrostatic interactions with 1,2,3-triazolyl and imidazolium, respectively., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Severe Acute Respiratory Syndrome (SARS) is a newly emerged, highly contagious disease. Health care workers remain the majority of total infections. The second SARS Medical Team of Peking University First Hospital was founded on May 1, 2003, which consist of 95 health care workers. During the working days in SARS wards and following isolation period no SARS cases were diagnosed. This investigation is aimed to give a detailed report on infection control precaution taken by this medical team. It was concluded that reasonable and strict infection control precaution help to reduce infection rate among health care workers, and careful supervision helped to achieve the reduction.

Objectives: To investigate the prevalence of SARS infection in medical workers and the efficacy of isolation precautions in the hospital., Methods: A retrospective analysis was employed to study the prevalence of SARS infection in medical workers who contacted with SARS patients directly. The data were analyzed with EPI statistic soft ware., Results: From March 15th, 2003 to May 18th, 2003, 224 patients with clinical confirmed SARS and 72 patients with clinical suspected SARS were presented in our hospital. The principle and system of the isolation precautions were established and implemented in our hospital. Seven hundreds and twenty medical workers including doctors, nurses and nurse-assistants were involved in the medical care of patients with SARS. Eighteen out of the 720 (2.43%) medical workers were infected with SARS, most of them were from the department of emergency, and the majority of infected medical workers were nurse-assistants. After the isolation precautions in hospital were established, the spreading of SARS in medical stuffs declined dramatically. The medical workers infected with SARS were 7.20% of SARS patients presented or hospitalized in our hospital. The infection rate was significantly lower than that of the average rate in our country., Conclusion: The isolation precautions taken in our hospital was effective.