Planar AIEgens with Enhanced Solid-State Luminescence and ROS Generation for Multidrug-Resistant Bacteria Treatment

Planar luminogens have encountered difficulties in overcoming intrinsic aggregation-caused emission quenching by intermolecular π-π stacking interactions. Although excited-state double-bond reorganization (ESDBR) can guide us on designing planar aggregation-induced emission (AIE) luminogens (AIEgens), its mechanism has yet been elucidated. Major challenges in the field include methods to efficiently restrict ESDBR and enhance AIE performance without using bulky substituents (e.g., tetraphenylethylene and triphenylamine). In this study, we rationally developed fluoro-substituent AIEgens with stronger intermolecular H-bonding interaction for restricted molecular motions and increased crystal density, leading to decreased nonradiative decay rate by one order of magnitude. The adjusted ESDBR properties also show a corresponding response to variation in viscosity. Furthermore, their aggregation-induced reactive oxygen species (ROS) generations have been discovered. The application of such planar AIEgen in treating multidrug-resistant bacteria has been demonstrated in a mouse model. The relationship between ROS generation and distinct E/Z-configurational stacking behaviors have been further understood, providing a design principle for synthesizing planar AIEgen-based photosensitizers.     

Synthesis and characterization of a Ruddlesden-Popper compound: Sr3FeMoO7

A powder sample of Sr₃FeMoO₇ was synthesized by solid-state reaction in reduced atmosphere (5% H₂/Ar). At room temperature, Sr₃FeMoO₇ crystallizes in a typical Ruddlesden-Popper (n=2) structure in the space group I4/mmm, and . The structure refinement indicates that the Fe and Mo ions are randomly distributed in a single B-site with small fraction of B-site and oxygen vacancies. At low temperature, long-range magnetic interaction was observed. The antiferromagnetic magnetic interaction can be described with a large unit cell, and c_m=c_n, in the magnetic space group An′.     

Covalent immobilization of Candida antarctica lipase B on nanopolystyrene and its application to microwave-assisted esterification

Nanopolystyrene was used as a solid support for the covalent immobilization of Candida antarctica lipase B (CalB) using the photoreactive reagent 1-fluoro-2-nitro-4-azido benzene (FNAB) as a coupling reagent. The obtained derivative was then used as a biocatalyst in a microwave assisted esterification experiment. Factors such as contact time, pH, and enzyme concentration were investigated during immobilization. The hydrolytic activity, thermal, and operational stability of immobilized-CalB were determined. The maximum immobilized yield (218 μg/mg support) obtained at pH 6.8 exhibited optimum hydrolytic activity (4.42 × 10³ mU p-nitrophenol/min). The thermal stability of CalB improved significantly when it was immobilized at pH 10, however, the immobilized yield was very low (93.6 μg/mg support). The immobilized-CalB prepared at pH 6.8 and pH 10 retained 50% of its initial activity after incubation periods of 14 and 16 h, respectively, at 60 ℃. The operational stability was investigated for the microwave assisted esterification of oleic acid with methanol. Immobilized-CalB retained 50% of its initial activity after 15 batch cycles in the microwave-assisted esterification. The esterification time was notably reduced under microwave irradiation. The combined use of a biocatalyst and microwave heating is thus an alternative total green synthesis process.     

A chemoenzymatic total synthesis of the phytotoxic undecenolide (-)-cladospolide A

An eleven-step synthesis of the title compound (1) from biocatalytically-derived and enantiomerically pure 'building blocks' alcohol (R)-(-)-9 and ester 13 is described. Attempts to construct the twelve-membered lactone ring of cladospolide A in a direct manner by using a ring-closing metathesis (RCM) reaction failed. However, a ten-membered lactone 19, could be constructed by such means and this was then subject to a two-carbon homologation sequence involving, inter alia, Wadsworth-Horner-Emmons and Yamaguchi lactonisation reactions in the closing stages of the synthesis. The impact of substituent stereochemistries and protecting groups on the RCM reaction leading to various ten-membered lactones is also described.     

Field-induced magnetic form factor of lutetium

The conduction electron field-induced magnetic form factor of Lu, a rare earth metal with a closed 4f shell, has been measured using the polarized neutron technique. The measurements demonstrate that the conduction electron density is more spatially extended than in the free atom. The experimental results are in good agreement with band calculations of the $\text{spin}$ magnetic form factor.     

南极假丝酵母在纳米聚苯乙烯上的共价固载及其在微波辅助酯化反应中的应用（英文）

Nanopolystyrene was used as a solid support for the covalent immobilization of Candida antarctica lipase B(Cal B) using the photoreactive reagent 1‐fluoro‐2‐nitro‐4‐azido benzene(FNAB) as a cou‐pling reagent. The obtained derivative was then used as a biocatalyst in a microwave assisted ester‐ification experiment. Factors such as contact time, pH, and enzyme concentration were investigated during immobilization. The hydrolytic activity, thermal, and operational stability of immobi‐lized‐Cal B were determined. The maximum immobilized yield(218 μg/mg support) obtained at pH 6.8 exhibited optimum hydrolytic activity(4.42 × 103 mU p‐nitrophenol/min). The thermal stability of Cal B improved significantly when it was immobilized at pH 10, however, the immobilized yield was very low(93.6 μg/mg support). The immobilized‐Cal B prepared at pH 6.8 and pH 10 retained 50% of its initial activity after incubation periods of 14 and 16 h, respectively, at 60 °C. The opera‐tional stability was investigated for the microwave assisted esterification of oleic acid with metha‐nol. Immobilized‐Cal B retained 50% of its initial activity after 15 batch cycles in the micro‐wave‐assisted esterification. The esterification time was notably reduced under microwave irradia‐tion. The combined use of a biocatalyst and microwave heating is thus an alternative total green synthesis process.