The 1,3-Dipolar Cycloadditions of Nitrile Oxides and Nitrile Imines to Alkyl Dicyanoacetates

The readily available alkyl dicyanoacetates 1 reacted with the 1,3-dipolar reagents arenecarbonitrile oxides 2 ′ and arenecarbonitrile imines 5 ′ to afford 1,2,4-oxadiazol and 1,2,4-triazol derivatives. The arenecarbonitrile oxides 2 ′ with electron-donating groups on the arene ring gave products 3a – d resulting from addition on both CN groups of 1 , and those with electron-withdrawing groups provided mono-adducts 4a – e (Scheme 1). Arylnitrile imines 5 ′ reacted with 1 to offer both bis- and mono-addition products (Scheme 2); the bis-adducts 8a , b possess an ester structure, whereas the mono-adducts 6a – d present a ketene-hemiacetal structure.     

Uniform hierarchical silica film with perpendicular macroporous channels and accessible ordered mesopores for biomolecule separation

Herein, we demonstrate that silica films with perpendicular macroporous channels and accessible ordered mesopores can be conveniently prepared. The hierarchical macroporous–mesoporous silica films are synthesized by using zinc oxide nanorod array as macroporous template and CTAB surfactant as mesoporous template. In basic surfactant-containing solution, ordered mesoporous silica shells homogeneously grow on the zinc oxide nanorod array. The growth of the mesostructures do not require any chemical modification for the zinc oxide nanorod, which opens a new way for preparing hierarchical silica films with perpendicular mesochannels. The prepared hierarchical macroporous–mesoporous silica films possess a uniform thickness of 2 mm, large perpendicular macropores with a length of 1.8 mm and a width of 80 nm, and accessible ordered mesopores. Separation experiment demonstrates that this macroporous–mesoporous film can effectively separate biomolecules with different sizes.     

Structural and process controls of AIEgens for NIR-II theranostics

Aggregation-induced emission (AIE) is a cutting-edge fluorescence technology, giving highly-efficient solid-state photoluminescence. Particularly, AIE luminogens (AIEgens) with emission in the range of second near-infrared window (NIR-II, 1000–1700 nm) have displayed salient advantages for biomedical imaging and therapy. However, the molecular design strategy and underlying mechanism for regulating the balance between fluorescence (radiative pathway) and photothermal effect (non-radiative pathway) in these narrow bandgap materials remain obscure. In this review, we outline the latest achievements in the molecular guidelines and photophysical process control for developing highly efficient NIR-II emitters or photothermal agents with aggregation-induced emission (AIE) attributes. We provide insights to optimize fluorescence efficiency by regulating multi-hierarchical structures from single molecules (flexibilization) to molecular aggregates (rigidification). We also discuss the crucial role of intramolecular motions in molecular aggregates for balancing the functions of fluorescence imaging and photothermal therapy. The superiority of the NIR-II region is demonstrated by fluorescence/photoacoustic imaging of blood vessels and the brain as well as photothermal ablation of the tumor. Finally, a summary of the challenges and perspectives of NIR-II AIEgens for in vivo theranostics is given.

Structural and process controls of NIR-II AIEgens realize manipulating of radiative (R) and nonradiative (NR) decay for precise theranostics.     

多支链烷基苯磺酸钠水溶液的表面性质

用自制的四种高纯度多支链烷基苯磺酸钠,研究了支链结构对其表面性质的影响.结果表明,随支链烷基碳数增加,临界胶束浓度降低,标准吸附自由能DGadӨ更负;但是,饱和吸附量Γmax却随支链烷基碳数增加而减小,且临界胶束浓度时的表面张力γcmc随吸附量减小而降低,表现出与一般表面活性剂不同的变化趋势.从多支链烷基苯磺酸钠的分子结构特点,解释了随支链烷基碳数增加Γmax和γcmc的变化规律,探讨了分子的独占面积(as)对Γmax及γcmc的影响.     

Influence of demulsifiers of different structures on interfacial dilational properties of an oil-water interface containing surface-active fractions from crude oil

The influences of two commercial demulsifiers that have a straight chain and branch chain, respectively, on the dilational viscoelasticity of an oil-water interfacial film containing surface-active fractions from crude oil were investigated. The branch-chain demulsifier AE-121 could efficiently substitute surface-active fractions of different average molecular weights from the oil-water interface, while straight-chain SP-169 could only efficiently substitute those of large average molecular weight. It was apt to form a mix-adsorption layer with surface-active fractions of small average molecular weight. The results showed that the molecular size (or represented by average molecular weights) of the surface-active fractions was an important factor influencing the reciprocity of demulsifiers and surface-active fractions at the oil-water interface. This effect could be well explained by the difference between sizes of surface-active fraction molecules and vacancies between demulsifier molecules at the interface. The results of SDBS also proved this explanation.     

CuAl2O4 powder synthesis by sol-gel method and its photodegradation property under visible light irradiation

Nanocrystalline spinel CuAl₂O₄ powders were prepared by sol-gel method from nitrate Cu(NO₃)₂·3H₂O, Al(NO₃)₃·9H₂O and complex C₆H₈O₇·H₂O. Sintering was carried out at 400, 500, 600, 700, 800°C respectively for 2 h in air. The XRD patterns started to appear CuAl₂O₄ peaks after sintering of 500°C and consist of only CuAl₂O₄ peaks as spinel crystal after sintering of 700°C. The powders were analyzed by TEM and UV-vis diffuse reflectance spectrum to be round, about 10–30 nm in size and Eg=1.77 eV. Photodegradation property of nanocrystalline CuAl₂O₄ powders was investigated by using methyl orange as model pollutant and mercury lamp (λ>400 nm) as energy source. The results indicated that CuAl₂O₄ powders sintered at 700°C had the excellent visible photocatalytic property. Under the irradiation of visible light, methyl orange could be degraded 97% in 120 min.     

Tuning Ground States of Bis(triarylamine) Dications: From a Closed‐Shell Singlet to a Diradicaloid with an Excited Triplet State

Three bis(triarylamine) dications were isolated by using weakly coordinating anions. Their electronic structures in the ground state were investigated by various experiments in conjunction with theoretical calculations. The ground‐state electronic structures of these species were tunable by substituent effects, with two of them as closed‐shell singlets and one of them as an open‐shell singlet in the solid state. The excited state of the latter is thermally accessible, indicated by EPR and SQUID measurements. The work provides a new and stable diradicaloid structure motif with an excited triplet sate.     

Electrostatic Interactions Leading to Hierarchical Interpenetrating Electroconductive Networks in Silicon Anodes for Fast Lithium Storage

Recently, the frequency of combining MXene, which has unique properties such as metal-level conductivity and large specific surface area, with silicon to achieve excellent electrochemical performance has increased considerably. There is no doubt that the introduction of MXene can improve the conductivity of silicon and the cycling stability of electrodes after elaborate structure design. However, most exhaustive contacts can only improve the electrode conductivity on the plane. Herein, a MXene@Si/CNTs (HIEN-MSC) composite with hierarchical interpenetrating electroconductive networks has been synthesized by electrostatic self-assembly. In this process, the CNTs are first combined with silicon nanoparticles and then assembled with MXene nanosheets. Inserting CNTs into silicon nanoparticles can not only reduce the latter‘s agglomeration, but also immobilizes them on the three-dimensional conductive framework composed of CNTs and MXene nanosheets. Therefore, the HIEN-MSC electrode shows superior rate performance (high reversible capacity of 280 mA h⁻¹ even tested at 10 A g⁻¹), cycling stability (stable reversible capacity of 547 mA h g⁻¹ after 200 cycles at 1 A g⁻¹) and applicability (a high reversible capacity of 101 mA h g⁻¹ after 50 cycles when assembled with NCM622 into a full cell). These results may provide new insights for other electrodes with excellent rate performance and long-cycle stability.