Radical Cation Salt‐initiated Aerobic C−H Phosphorylation of N‐Benzylanilines: Synthesis of α‐Aminophosphonates

A radical cation salt‐initiated phosphorylation of N‐benzylanilines was realized through an aerobic oxidation of the sp³ C?H bond, providing a series of α‐aminophosphonates in high yields. An investigation of the reaction scope revealed that this mild catalyst system is superior in good functional group tolerance and high reaction efficiency. The mechanistic study implied that the cleavage of the sp³ C?H bond was involved in the rate‐determining step.     

The influence of fractal size distribution of covers on radon exhalation from uranium mill tailings

Tailings produced during mining and milling of uranium ores represent potentially large volumes of low level radioactive materials. A typical environmental problem associated with mill tailings is radon emanation. Covering tailings is widely applied to reduce radon exhalation rate. In this paper, the fractal theories and field covering tests are used to study the fractal characters of size distribution of six types of covering materials, including waste rock, sand, laterite, kaolin, mixture of sand and laterite, and mixture of waste rock and laterite, and their influences on radon exhalation. The size distributions of uranium tailings and the six aforementioned covering materials all exhibit a good fractal structure. The contents of fine grain increase with the increasing value of fractal dimension. The results of field radon measurement show that the radon emanation rate of tailings without covers is 14.7–18.6 Bq/m² s. Covering tests were carried out of the six abovementioned covering materials with thickness of 0.4 m, 0.8 m, 1.2 m, 1.6 m and 2.0 m. The results indicate that the application of these materials for cover layers can decrease the radon exhalation rate markedly. The effectiveness of a cover layer in reducing radon exhalation is related to its fractal texture of size distribution. Under the same thickness conditions, the attenuation coefficient of radon exhalation rate increases with the increasing fractal dimension of size distribution of covers. The empirical expressions of the attenuation coefficients in relation to fractal dimension D of size distribution and thickness x of covers is obtained for evaluating the effectiveness of final covers for uranium tailings impoundments.     

AIE荧光聚合物RAFT可控合成与表征及光物理性质研究

聚集诱导发光(AIE)分子是与传统的聚集态荧光淬灭染料分子具有截然相反的光物理性质的新型有机发光材料,可广泛应用于化学/生物传感、生物探针与成像、诊疗一体化和光电子器件等诸多领域中。本论文通过可逆加成-断裂链转移(RAFT)聚合方法,可控合成了侧链型四苯乙烯TPE聚丙烯酸酯AIE聚合物。通过实验条件的优化与探索,尤其采用半衰期较短、活性更高的偶氮二异庚腈(ABVN)取代常规的偶氮二异丁腈(AIBN)引发剂,将原来超过12 h的过夜反应前沿科研实验,改造为较短的3–5 h聚合反应时间内即可达到中等收率和较好的聚合物产品质量,使其成为一个适合本科教学环境的新创实验。本实验融合了无水无氧操作技术、柱层析分离纯化、RAFT可控聚合和GPC分子表征技术、FTIR、NMR、UV-Vis、荧光光谱等多种现代实验技术和表征方法,考查了所合成四苯乙烯TPE侧基的AIE聚合物的光物理性质,测定其溶液中的相对荧光量子产率达17%。     

官能化反蛋白石结构光子晶体的构筑及对肝素的检测

制备了一种具有反蛋白石结构的光子晶体(IOPCs), 通过聚乙烯亚胺(PEI)实现了对该IOPCs的官能化; PEI官能化的IOPCs与肝素之间具有强静电作用, 从而可利用其对肝素进行特异性检测. 研究结果表明, 随着肝素浓度的增加(0~10 ^-4 mol/L), 官能化IOPCs的布拉格衍射峰最大位移约为40 nm; 肝素浓度的对数与IOPCs的最大衍射波长位移具有良好的线性关系(R ²=0.99905), 检测限为10 ^-10 mol/L. 该IOPCs具有较好的物理和化学稳定性, 且能重复用于肝素的检测, 具有良好的应用前景.     

Blood compatible heteratom-doped carbon dots for bio-imaging of human umbilical vein endothelial cells

Carbon dots have unique advantages in biological applications owing to their excellent optical prope rties.However,the biosafety evaluation of carbon dots has limitations owing to cytotoxicity in vitro,and the re is little pre-safety evaluation before in vivo and clinical applications.Whether the carbon dots are or not suitable for applications in vivo,evaluation analysis can be made based on hemolysis and changes in erythrocyte morphology.In this work,a green fluorescent N,S-doped carbon dots(N,S-CDs)were obtained by hydrothermal method,tobias acid,and m-phenylenediamine as precursors.N,S-CDs not only possessed excellent dispersibility,uniform particle size,high quantum yield(37.2%)and stable photoluminescence property but also retain their photostability and stro ng fluorescence intensity in the acid/alkaline solutions,different ionic strengths(NaCl)and under 365 nm UV illumination.Moreove r,the N,S-CDs displayed low cytotoxicity and high cellular uptake efficiency in human umbilical vein endothelial cells(HUVEC)and excellent blood compatibility to the erythrocyte.It is foreseeable that N,S-CDs could be further studied as a promising biological imaging agent in vivo.     

Controlled Radical Copolymerization toward Well-Defined Fluoropolymers

In the past 80 years, fluoropolymers have found broad applications in both industrial and academic settings, owing to their unique physicochemical properties. Copolymerizations of fluoroalkene feedstocks present an important avenue to obtain high-performance materials by merging intrinsic attributes of fluorocarbons and great versatility of comonomers. Recently, while massive investigations have disclosed the great potentials of precisely synthesized polymers, researchers have made considerable efforts to approach well-defined fluorinated copolymers. This minireview discusses challenges in controlled radical copolymerizations (CRCPs) of fluoroalkenes and provides a concise perspective on recent progress in CRCPs of fluoroalkenes (e.g., tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropene, perfluoroalkyl vinyl ethers) with non-fluorinated vinyl comonomers, which have enabled on-demand preparations of various main-chain fluoropolymers with predefined molar masses, low dispersities, as well as regulable chemical compositions and sequences. The synthetic advantages of CRCPs will promote controlled and facile access to customized fluoropolymers for high-tech applications such as batteries, coatings and so on.