选择性响应Cu~(2+)、Ag~+及阴离子的菲咯啉-水杨醛荧光探针

在乙酸酐中用2,9-二甲基-1,10-菲咯啉与水杨醛缩合反应得到2,2′-(1E,1′E)-2,2′-(1,10-菲咯啉-2,9-二基)双(乙烯-2,1-二基)双(2,1-亚苯基)二乙酸酯(探针1);再将其进一步水解得到2,2′-(1E,1′E)-2,2′-(1,10-菲咯啉-2,9-二基)双(乙烯-2,1-二基)二苯酚(探针2)。经1H NMR、13C NMR、IR、MS表征,探针化合物为大共轭结构,发光性能良好。两种探针分别表现出对Cu2+、Ag+不同的荧光猝灭作用,探针2还能识别阴离子F-和AcO-,具有双功能离子检测性能。光谱滴定、等温滴定量热及质谱等测定了配合物组成、作用常数及热力学参数,探针与金属离子的配合为放热反应,作用比为2∶1。     

N-烷基丙烯酰胺温敏聚合物合成研究进展

聚N-烷基丙烯酰胺因表现出温度敏感的特殊性能而成为高分子领域的研究热点,具有非常好的应用潜力。本文评述了线性和聚凝胶化N-烷基丙烯酰胺温敏聚合物的合成研究进展,分别介绍了水溶液自由基聚合合成线性N-烷基丙烯酰胺温敏聚合物的研究进展和化学交联、物理交联、辐射交联聚合凝胶化N-烷基丙烯酰胺温敏聚合物的合成研究进展,并对线性温敏聚合物和凝胶化文敏聚合物合成方法优缺点、单体选择、应用范围进行了讨论。     

1,4-二酮吡咯并吡咯在聚合物太阳能电池的应用

1,4-二酮吡咯并吡咯(DPP)由于具有优异的共平面性和强烈的拉电子能力,从而被引入D-A型窄带隙共轭聚合物中调控聚合物材料的能隙和能级结构,拓宽在可见光区域的响应范围。近年来,DPP类聚合物太阳能电池材料的研究受到广泛关注,目前基于DPP的聚合物太阳能电池效率高已达9.64%。本文探讨了以DPP作为受体单元而噻吩衍生物、芴、咔唑和苯并二噻吩等作为给体单元制成的D-A型窄带隙共轭聚合物太阳能电池的研究进展,并探讨了聚合物材料结构与太阳能电池性能之间的内在构效关系。     

多壁碳纳米管修饰玻碳电极测定铜离子

以多壁碳纳米管(MWCNTs)修饰玻碳电极为工作电极,采用阳极溶出线性扫描法研究了铜离子的电化学测定方法。探讨了MWCNTs修饰层数、富集电位、富集时间、溶液pH、支持电解质对峰电流的影响。实验表明,铜离子浓度在1.0×10-8~1.0×10-5mol·L-1范围内与峰电流呈良好的线性关系,检测限为2.0×10-9mol·L-1,且该电极具有良好的稳定性和抗干扰能力。     

固相萃取富集/气相色谱法测定烟草中的9种有机酸

建立了用硫酸甲醇甲酯化衍生-固相萃取富集/气相色谱测定烟草中9种有机酸的方法,首次实现了强酸介质中有机酸酯的固相萃取。烟草样品用硫酸-甲醇进行甲酯化衍生,衍生生成的有机酸酯用MCIGEL反相树脂分离富集,萃取液用甲醇洗脱后进行气相色谱分析,采用DB-5毛细管色谱柱,进样量1.0μL,不分流进样;检测器温度250℃。方法可同时准确测定烟草样品中乳酸、草酸、丙二酸、乙酰丙酸、苹果酸、柠檬酸、棕榈酸、硬脂酸、亚油酸的含量,各有机酸的加标回收率为92.2%~102.6%,相对标准偏差为2.4%~3.2%,定量下限为0.20~0.36 mg/L。该方法准确、灵敏度高,能够满足实际样品的测定要求。     

A New Near-Infrared Neutral pH Fluorescent Probe for Monitoring Minor pH Changes and its Application in Imaging of HepG2 Cells

A new near-neutral pH near-infrared (NIR) fluorescent probe utilizing a fluorophore–receptor molecular framework that can modulate the fluorescence emission intensity through a fast photoinduced electron transfer process was developed. Our strategy was to choose tricarbocyanine (Cy), a NIR fluorescent dye with high extinction coefficients, as a fluorophore, and N-methylpiperazine (MP) as a receptor. The pH titration indicated that MP-Cy can monitor the minor physiological pH fluctuations with a pKa of ～7.10 near physiological pH, which is valuable for intracellular pH researches. The probe responds linearly and rapidly to minor pH fluctuations within the range of 3.05–7.10 and exhibits strong dependence on pH changes. As expected, the real-time imaging of cellular pH and the detection of pH in situ was achieved successfully in living HepG2 cells by this probe. It is shown that the probe effectively avoids the influence of autofluorescence and native cellular species in biological systems and meanwhile exhibits high sensitivity, good photostability, and excellent cell membrane permeability.     

pH-responsive pseudorotaxane between comblike PEO-grafted triblock polymer and α-cyclodextrin

The pH-responsive inclusion complexation of comblike triblock polymer, P2VP-b-PPEOMA-b-P2VP, with α-cyclodextrin (α-CD) was studied. The triblock polymer was prepared by reversible addition–fragmentation chain transfer polymerization (RAFT) and formed inclusion complexes (ICs) after selective threading of the PEO segment of the triblock polymer through the cavities of α-CD units. For comparison, PPEOMA homopolymer was prepared, and the inclusion complexation with α-CD was also studied. The formed ICs were characterized by XRD and ¹H NMR. The results revealed that P2VP-b-PPEOMA-b-P2VP can form ICs with α-CD even when forming micelles, and the introduction of P2VP had a great influence on the solution property and the stoichiometry of EO to CD of the inclusion complexes depending on the concentration and the pH of the solution.     

Waste Biogas Residue from Cassava Dregs as Carbon Source to Produce Galactomyces sp. Cczu11-1 Cellulase and its Enzymatic Saccharification

In the conversion of cassava starch dregs to biogas by anaerobic fermentation, the biogas residue (BR) containing lignocellulosic materials still remained in the environment. In order to effectively utilize BR, the complexed 1-methyl-3-methylimidazolium dimethyl phosphate ([Mmim]DMP) media were used for pretreating cellulosic materials. After the optimization of pretreatment, the IL [Mmim]DMP-HCl-water (78.5:1.5:20, w/w/w) pretreament media were used for pretreating BR at 130 °C for 30 min. Furthermore, BR pretreated could be effectively saccharified by cellulase of Galactomyces sp. CCZU11-1. Moreover, BR could be used as a cheap carbon source for the production of Galactomyces sp. CCZU11-1 cellulase. After the culture optimization, the optimal culture conditions were obtained as follows: BR 5 g/L, (NH₄)₂SO₄ 5 g/L, K₂HPO₄ 2 g/L, MgSO₄ 0.2 g/L, NaCl 1 g/L, PEG6000 4 g/L, pH 5.5, and culture temperature 30 °C. After the fermentation for 6 days, the FPA and CMCase were 26.2 and 52.8 U/mL, respectively. In conclusion, waste BR could be chosen as a promising feedstock for biofuels.     

Sol–gel preparation and characterization of Bi4(Si1−xGex)3O12 solid solutions

Micro-crystals of Bi₄(Ge_xSi_1?x)₃O₁₂ (x = 0, 0.25, 0.5, 0.75, 1) solid solution series were synthesized by a sol–gel method, using stoichiometric Si(OC₂H₅)₄, GeO₂, Bi(NO₃)₃·5H₂O as the starting materials. The as-prepared series were studied by X-ray diffraction, Raman spectra, differential thermal analysis, and fluorescence spectra. Experiments showed that single phase of Bi₄(Si_1?xGe_x)₃O₁₂ was obtained by the sol–gel method. For all the composition, Bi₄Si₃O₁₂ and Bi₄Ge₃O₁₂ can completely dissolve into each other. The refined cell parameters were in proportion to the composition. Bi₄Ge₃O₁₂ showed the strongest fluorescence emission while Bi₄Si₃O₁₂ showed the weakest fluorescence emission.     

A Pressure-Induced Inverse Order–Disorder Transition in Double Perovskites

Given the consensus that pressure improves cation ordering in most of known materials, a discovery of pressure-induced disordering could require recognition of an order–disorder transition in solid-state physics/chemistry and geophysics. Double perovskites Y₂CoIrO₆ and Y₂CoRuO₆ polymorphs synthesized at 0, 6, and 15 GPa show B-site ordering, partial ordering, and disordering, respectively, accompanied by lattice compression and crystal structure alteration from monoclinic to orthorhombic symmetry. Correspondingly, the long-range ferrimagnetic ordering in the B-site ordered samples are gradually overwhelmed by B-site disorder. Theoretical calculations suggest that unusual unit-cell compressions under external pressures unexpectedly stabilize the disordered phases of Y₂CoIrO₆ and Y₂CoRuO₆.