A 3D Luminescent Metal‐organic Framework Constructed from Cu4I4 Cubane Clusters and Triangular Imidazole Ligand

Abstract . The solvothermal reaction between cuprous iodide and the rigid triangular imidazole ligand in mixed N,N′‐dimethylacetamide (DMA)‐acetonitrile solvent leads to the isolation of the 3D metal‐organic framework [(Cu₄I₄)₃(TIPA)₄] · 7DMA ( 1 ) [TIPA = tri(4‐imidazolylphenyl) amine], which was characterized by elemental analysis, IR spectroscopy, powder X‐ray diffraction, and single‐crystal X‐ray diffraction. Topologically, the structure of 1 is an unprecedented 3,3,4,4‐connected net with a point symbol of {4.8.10}₂{4.8²}₂{4².8².10²}₂{8⁴.12²}. Compound 1 exhibits orange‐red photoluminescence with an emission maximum at 622 nm at room temperature.     

Ultrathin two-dimensional MnO2 nanosheet as a stable coreactant of 3,3′,5,5′-tetramethylbenzidine chromogenic substrate for visual and colorimetric detection of iron(II) ion

Microchimica Acta - The authors report on a chromogenic system based MnO2 nanosheet and the chomgenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB). The MnO2 nanosheet can oxidize TMB...     

Determining the full transformation relations in the transformation method

The transformation method provides an efficient way to control wave propagation by materials. However, the degree to which this transformation concept can be applied to other physical phenomena remains an open question. Recently, Hu et al. presented a general framework for determining the transformation relations of the physical quantities in an arbitrary partial differential equation (PDE) in its application scope according to the idea of the transformation method. In this paper, we will review the main concepts of this general theory, particularly the difference between this idea and usual methods. The flexibility of this method is shown using an example.     

A finite element model using multi-layered shell element in laser forming

Due to its enormously high flexibility laser forming has been gaining importance in recent years. This rapidness and flexibility demand very precise controlling strategies especially when simulating the process of large plates and challenging the limited computation power of the current workstation. A simple, robust and accurate modeling method of laser forming has been demonstrated to solve this problem. The simplified model is meshed by multi-layered shell element, simulated with a more real scanning method and fewer parameters. The intelligent meshing strategies have reduced the number of elements dramatically. Thus the simulation efficiency has been improved significantly. By comparing the simulation results under the simplified model with the results under the traditional model for laser forming, the applicability of proposed method has been proven. The method of these simplified models is also suitable to simulate complex finite element models, which take much time to simulate. It would throw some light on the thermal mechanically coupled-field simulation of large sheet.     

Oxidation for unsymmetrical bromo-1,10-phenanthrolines and subsequent hydroxylation,decarbonylation and chlorination reactions

A systematic investigation on the oxidation of unsymmetric bromo-phens is presented herein, where the reaction temperature is found to be the key parameter to generate oxidation or oxidation-bromination products. The regioselective C3-brominated compounds are produced in moderate yields in the cases of 2-bromo-phen and 4-bromo-phen. Subsequent hydroxylation and decarbonylation for bromo-phds are also studied, where a series of bromo-diazafluorenones and phen-triones have been isolated. Furthermore, various chlorination products have been obtained by treating bromo-phds or bromo-phts with excess POCl₃.     

Study on the mechanism of catalytic synthesis of dimethyldichlorosilane by AlCl3/MIL‐53(Al)@γ‐Al2O3

Dimethyldichlorosilane, one of the most consumed organosilicon monomers in the industry, can be prepared in a highly efficient and environmentally friendly synthesis method of disproportionating methylchlorosilanes. However, the internal mechanism of the reaction remains unclear. In this paper, the mechanism catalyzed by AlCl₃/MIL‐53(Al) and AlCl₃/MIL‐53(Al)@γ‐Al₂O₃ catalysts was calculated at B3LYP/6‐311++G(3df, 2pd) level by using the density functional theory (DFT). The results showed that although the two catalysts had similar active structures, the catalytic effects were significantly different. The Lewis acid center on the surface of γ‐Al₂O₃ in the core‐shell catalyst is complementary to the classic Lewis acid AlCl₃ through the spatial superposition effect, which greatly improves the Lewis acid catalytic activity of AlCl₃/MIL‐53(Al)@γ‐Al₂O₃.     

A Bait-and-Switch Method for the Construction of Artificial Esterases for Substrate-Selective Hydrolysis

Outcomes of chemical reactions are generally dominated by the intrinsic reactivities of reaction partners, but enzymes frequently override such constraints to transform less reactive molecules in the presence of more reactive ones. Despite the attractiveness of such catalysis, it is difficult to build synthetic catalysts with these features. Micellar imprinting is a powerful method to create template-complementary binding sites inside protein-sized water-soluble nanoparticles. When a photocleavable functional monomer was used to bind two phosphonate/phosphate templates as transition-state analogues, active sites with predetermined size and shape were formed inside doubly cross-linked micelles through molecular imprinting. Postmodification replaced the binding group with a catalytic pyridyl group, forming highly selective artificial esterases. The catalysts displayed enzyme-like kinetics and turnover numbers that were in the hundreds. The selectivity of the catalysts, derived from the substrate-complementary imprinted active sites, enabled transformation of less reactive esters in the presence of more reactive ones.     

Vertically Grown Few-Layer MoS2 Nanosheets on Hierarchical Carbon Nanocages for Pseudocapacitive Lithium Storage with Ultrahigh-Rate Capability and Long-Term Recyclability

Molybdenum disulfide (MoS₂) is an intensively studied anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity, but it is still confronted by severe challenges of unsatisfactory rate capability and cycle life. Herein, few-layer MoS₂ nanosheets, vertically grown on hierarchical carbon nanocages (hCNC) by a facile hydrothermal method, introduce pseudocapacitive lithium storage owing to the highly exposed MoS₂ basal planes, enhanced conductivity, and facilitated electrolyte access arising from good hybridization with hCNC. Thus, the optimized MoS₂/hCNC exhibits reversible capacities of 1670 mAh g⁻¹ at 0.1 A g⁻¹ after 50 cycles, 621 mAh g⁻¹ at 5.0 A g⁻¹ after 500 cycles, and 196 mAh g⁻¹ at 50 A g⁻¹ after 2500 cycles, which are among the best for MoS₂-based anode materials. The specific power and specific energy, which can reach 16.1 kW and 252.8 Wh after 3000 cycles, respectively, indicate great potential in high-power and long-life LIBs. These findings suggest a promising strategy for exploring advanced anode materials with high reversible capacity, high-rate capability, and long-term recyclability.