4-Phosphoryl Pyrazolones for Highly Selective Lithium Separation from Alkali Metal Ions

Effective receptors for the separation of Li⁺ from a mixture with other alkali metal ions under mild conditions remains an important challenge that could benefit from new approaches. In this study, it is demonstrated that the 4-phosphoryl pyrazolones, H L ²-H L ⁴, in the presence of the typical industrial organophosphorus co-ligands tributylphosphine oxide (TBPO), tributylphosphate (TBP) and trioctylphosphine oxide (TOPO), are able to selectively recognise and extract lithium ions from aqueous solution. Structural investigations in solution as well as in the solid state reveal the existence of a series of multinuclear Li⁺ complexes that include dimers (TBPO, TBP) as well as rarely observed trimers (TOPO) and represent the first clear evidence for the synergistic role of the co-ligands in the extraction process. Our findings are supported by detailed NMR, MS and extraction studies. Liquid-liquid extraction in the presence of TOPO revealed an unprecedented high Li⁺ extraction efficiency (78 %) for H L ⁴ compared to the use of the industrially employed acylpyrazolone H L ¹ (15 %) and benzoyl-1,1,1-trifluoroacetone (52 %) extractants. In addition, a high selectivity for Li⁺ over Na⁺, K⁺ and Cs⁺ under mild conditions (pH ∼8.2) confirms that H L ²-H L ⁴ represent a new class of ligands that are very effective extractants for use in lithium separation.     

d-Orbital Reconstructions Forced by Double Bow-Shaped Deformations and Second Coordination Sphere Effects of Cu(II) Heme Analogs in HER**

Both geometric architecture and electronic configurations of heme proteins contribute to its activity. In this work we designed and synthesized a series of four copper(II) porphyrin complexes ( 4 -, 3 -, 2 - and 1 -Cu) where the molecular conformations are modulated by a pair of stepwise shortened straps on the same porphyrin side (cis-ortho) to give double bow-shaped skeletons. Single crystal structures demonstrate that the straps gradually increase the saddle deformation and the deviation of the metal centers, which is in accordance with two, unusual d-orbital reconstructions of two different ground states, as revealed by 4 K EPR and DFT calculations. In the study of the electrocatalytic hydrogen evolution reaction (HER), 1 -Cu, with the shortest straps, showed the most apparent improvement of activity. Second coordination sphere (SCS) effects created by the double bow-shaped architecture and the strong saddle porphyrin core in 1 -Cu are found to play key roles in proton trapping during the catalytic process. The work contributes a novel strategy to improve the catalytic performance of heme analogs through ligand geometric modulation.     

小分子基温敏聚合物纳米粒子的制备及在近红外二区荧光成像与光热治疗中的应用

以有机小分子4,9-二(5-9H-芴-2-基-噻吩-2-基)-6',7-联苯[1,2,5]噻二唑并[3,4-g]喹喔啉(TQF)为前驱体, 通过化学方法将其修饰为可引发可逆加成-断裂链转移聚合(RAFT)反应的小分子链转移剂TQF-苯基硫代链 转移剂（CTA）. 以TQF-CTA为链转移剂, 以偶氮二异丁腈为引发剂, 引发N-异丙基丙烯酰胺(NIPAAm)和 甲基丙烯酸寡聚乙二醇酯(OEGMA)发生RAFT聚合反应, 合成了具有良好水溶性和较低临界溶解温度(LCST)的小分子基共聚物[TQF-P(NIPAAm-co-OEGMA), TPNO]. 将其直接溶于水中可制备成温敏的球形纳米粒子 TPNO NPs. 研究结果表明, TPNO NPs在温度大于LCST(35 ℃)时表现出一个明显的粒径变化和显著的荧光 增强行为(2.2倍), 并成功实现了对活体小鼠血管与肿瘤的明亮近红外二区(NIR-Ⅱ)荧光成像(FI). 同时, TPNO NPs有着良好的光热转换效率(PCE=29.8%), 通过体外细胞实验证明了其对细胞具有较好的光热治疗(PTT)效果.     

单细胞核酸编码扩增成像分析

单细胞成像可在单细胞水平观测目标物位置、 确定目标物含量, 在生命科学与临床医学研究领域应用广泛. 核酸编码扩增技术利用特定分子反应将待测目标识别转化为核酸条码的扩增, 具有探针种类多、 易编程、 反应条件温和及信号放大效率高等特点, 在单细胞低丰度、 高灵敏、 多目标物成像中优势显著, 为理解细胞状态、 探索生命过程提供了新思路. 本文综合评述了核酸编码扩增在单细胞荧光成像领域的研究进展, 以目标物的编码方式为分类依据, 系统阐述了固定细胞原位成像和活细胞成像中不同目标物编码与扩增成像方式的区别, 并对活细胞成像中多重检测面临的问题以及未来发展前景进行了展望.     

中学化学教学中的科学思维与逻辑辨析

化学是一门具有创造性的基础科学,是环境、生命、医药、材料等科学的基础,在思维逻辑上彰显和蕴含了丰富的科学思维方法。系统总结化学科学思维方法,可以有效破解中学化学学习中的“繁,难,乱”。在多年的教学实践中,提出了化学科学多向思维方法体系,强调多层次思维过程中对多因素的立体逻辑思维辨析。重点介绍了与中学化学教学相关的零阶、初阶、中阶和高阶逻辑思维辨析的内涵,期望化学教学中重视化学思维逻辑过程,实现化学教与学在思维模式上的深层次发展与提升。     

Preparation and Properties of Poly（ether ether ketone）/Carbon Nanotube Modified Polypropylene Janus Composite Separator北大核心CSCD

Lithium-ion batteries （LIBs）have attracted wide attention because of their broad prospects in electric vehicles. However,the safety problems and low multiplier performance of the commercial polyolefin separator limit their further development,due to the poor dimensional thermal stability and low electrolyte absorption rate. Poly（ether ether ketone）（PEEK）and carbon nanotube（CNT）are compounded to coat on polypropylene （PP） to prepare Janus composite separator （PP@C） through the phase inversion method. PP@C composite separator does not deform at 180 ℃ for 0. 5 h（only slight deformation）,illustrating excellent thermal stability. The electrolyte absorption rate of PP@C2 is 193. 8%. The electrolyte uptake rate of the PP@C2 composite membrane was 193. 8%,which was 64. 5% higher than the PP membrane,showing a superduper electrolyte permeability. As a result,the specific discharge capacity of LIBs assembled with PP@C2 composite separator is 157. 6 mA·h/g at 0. 2 C and 129. 8 mA·h/g at 2 C,showing good rate performance with the capacity recovery rate of more than 99%. This might be attributed to the ultra-high thermal stability of PEEK,the good affinity of the electrolyte,the high conductivity of CNT,as well as the uniform dispersion of Li+ ,so that the separator can have excellent electrochemical performance while improving safety. © 2022, Science Press (China). All rights reserved.     

基于铜金属有机配合物的热活化延迟荧光材料

具有热活化延迟荧光(thermally activated delayed fluorescence, TADF)特性的配合物可以同时利用单重态和三重态激子,因此发光量子效率较高,近年来受到广大科研工作者的关注。特别是铜金属有机配合物,最低单重态和最低三重态的能量差较小,又可以通过不同配体或取代基进行调节,所以具有较好TADF性能。本文根据配位原子的类型,汇总和分析了近5年具有TADF性质的铜配合物的结构特点和发光性能,并简要讨论了其在有机发光二极管(organic light-emitting diodes,OLEDs)中的潜在应用。     

基于极少量采样的彩绘文物颜料成分分析

随着文物保护理念的提升,越来越提倡文物样品的无损或微损分析;同时由于文物样品的复杂性,对分析技术提出了更加严苛的要求.彩绘类文物的颜料分析研究,对其文物信息的提取,以及古代人类历史、社会、文化的研究和阐述具有重要作用.结合本研究组前期的研究成果,本研究提出了一种在极少量采样的情况下,分析研究文物颜料的方法,并用于榆林卧...     

改良QuEChERS-气相色谱-串联质谱法同时测定土壤中17种邻苯二甲酸酯

建立了改良的QuEChERS法,结合气相色谱-串联质谱(GC-MS/MS)检测土壤中17种邻苯二甲酸酯的分析方法.样品用乙腈水溶液提取,NaCl盐析分层,上清液采用磁性氧化石墨烯(Fe3O4-GO)、N-丙基乙二胺(PSA)和无水MgSO4吸附剂分散固相萃取净化,质谱以多反应监测(MRM)模式测定,外标法定量.结果 表...