Micro-solid phase equilibrium extraction with highly ordered TiO2 nanotube arrays: a new approach for the enrichment and measurement of organochlorine pesticides at trace level in environmental water samples

Ordered TiO₂ nanotube arrays have been widely used in many fields such as photocatalysis, self-cleaning, solar cells, gas sensing, and catalysis. This present study exploited a new functional application of the ordered TiO₂ nanotube arrays. A micro-solid phase equilibrium extraction using ordered TiO₂ nanotube arrays was developed for the enrichment and measurement of organochlorine pesticides prior to gas chromatography-electron capture detection. Ordered TiO₂ nanotube arrays exhibited excellent merits on the pre-concentration of organochlorine pesticides and lower detection limits of 0.10, 0.10, 0.10, 0.098, 0.0076, 0.0097, 0.016, and 0.023 μg L⁻¹ for α-HCH, β-HCH, γ-HCH, δ-HCH, p,p’-DDE, p,p’-DDD, o,p’-DDT, and p,p’-DDT, respectively, were achieved. Four real water samples were used for validation, and the spiked recoveries were in the range of 78–102.8%. These results demonstrated that the developed micro-solid phase equilibrium extraction using ordered TiO₂ nanotube arrays would be very constructive and have a great beginning with a brand new prospect in the analysis of environmental pollutants.     

现代教育技术在大学化学教学中的应用

探讨如何在传统教学手段的基础上,更好地整合现代教育技术与大学化学教学,使大学化学教学与时俱进,实现教学手段的现代化和最优化。     

小分子铱配合物及其电致发光

由于磷光金属配合物可以同时利用单线态和三线态激子发光,使有机电致发光器件的理论内量子效率达到100%,突破了25%的极限。因而以磷光金属配合物为发光材料制成的器件备受关注。在这些金属配合物中,铱配合物由于具有较强的发光特性、发光波长可调性、较好的热稳定性和电化学稳定性以及能够形成便于蒸镀的中性分子,而成为最有应用潜力的电致磷光材料。本文综述了近几年铱配合物磷光材料在分子设计与合成方法、发光机理及器件构筑等方面的研究进展。特别介绍与讨论了磷光铱配合物的两种发光机理,即基于同配体铱配合物或异配体铱配合物的主配体到中心金属离子的电荷转移三线态(³MLCT)发射和基于异配体铱配合物的辅助配体三线态(³LC)发射。根据反应条件的差异,归纳总结了合成铱配合物常用的4种方法以及合成fac式和mer式的铱配合物的方法。还根据材料的发光颜色及其电致发光的不同,对磷光铱配合物材料进行了分类与讨论。此外,简要介绍了用于器件制作的主体材料。最后,展望了金属有机配合物电致磷光材料的发展前景,并提出了今后磷光材料的发展方向。     

碳纳米管在药物载体领域的进展

基于其独特的结构、电子及机械性能,碳纳米管自被发现以来就是极具吸引力的材料,被广泛研究。在药物化学领域,碳纳米管成为载运治疗药物实现靶向治疗、控制释放等的热点,研究日益深入。本文概述了近年来碳纳米管在药物载体领域的研究进展情况,评述了其未来发展趋势,认为深入考察修饰碳纳米管的毒性,探索其载药释药机制,并逐步应用于临床,...     

含磺酸根侧链的聚苯乙炔-吡啶类共轭聚合物的荧光传感性能

利用Sonogashira偶合反应合成了两种新的含磺酸根侧链的聚苯乙炔-吡啶类共轭聚合物P1, P2. 通过紫外-可见吸收光谱和荧光光谱对其光学性质及Cu^2＋传感检测进行了研究. 结果表明, 按一定比例嵌段引入吡啶环的聚合物P1能有效地改善共轭主链的刚性, 提高检测的灵敏度, 使共轭聚合物具有更优异的荧光化学传感性能. 在甲醇溶剂中, P1 的荧光能被Cu^2＋有效地猝灭, 相对单体模型分子PESO₃, 其响应信号扩大222倍.     

Supramolecular frameworks composed of copper(II), zinc(II), and ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different molar ratios of metal and ligand

Abstract  

Three copper(II), one zinc(II), and one ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different metal/ligand molar ratios, formulated as [Cu(3-bromo-phen)(ClO₄)(C₃H₇NO)₂(H₂O)](ClO₄) (1), [Cu(3,8-dibromo-phen)(ClO₄)(C₃H₇NO)₂(H₂O)](ClO₄) (2), [Cu(3,8-dibromo-phen)(ClO₄)(H₂O)₃](ClO₄)(H₂O)₃ (3), [Zn(3,8-dibromo-phen)₂(H₂O)₂](ClO₄)₂(H₂O)₂ (4), and [Fe(3,8-dibromo-phen)₃](ClO₄)₂(H₂O)(CH₄O)(C₃H₆O)₂ (5) (phen = 1,10-phenanthroline), have been synthesized and characterized in this paper. X-ray single-crystal diffraction studies reveal the different crystallographic symmetry and packing fashions between neighboring phen rings in 1:1 Cu(II) complexes 1–3 due to the alteration of bromo substituent 1,10-phenanthroline ligands and coordinated or free solvent molecules. Additionally, in 1:2 Zn(II) and 1:3 Fe(II) complexes 4 and 5, continuous π–π stacking and alternating π–π and dimeric p–π stacking are found.     

Theoretical studies on N-loss predissociation mechanisms of N2O+ (A?2Σ+) in Cs symmetry

The N-loss predissociation mechanisms of the A ²Σ⁺ (2 ² A′) state of N₂O⁺ to the first and second dissociation limits were studied in the C _s symmetry. The potential energy curves (PECs) and minimum energy crossing points (MECPs) for the C _s states of N₂O⁺ were calculated at the CAS levels. On the basis of our CAS calculation results (CASPT2 energetic results and CASSCF spin orbit couplings), we suggest two processes for N-loss predissociation mechanisms of A ²Σ⁺ (2 ² A′) to the first and second limits. The first two steps in the two processes are the same: A ²Σ⁺ passes through the 2 ² A′/1 ⁴ A″ MECP and then reaches the 1 ⁴ A″ (1 ⁴Σ⁻) PEC. The 2 ² A′/1 ⁴ A″ MECP has a bent geometry and is slightly higher in energy than the transition state along the 1 ⁴ A″ PEC. Our mechanisms are different from the previously suggested mechanisms (via 1 ⁴Π).     

MnO_x-CeO_2上表面氧性质及其催化碳烟燃烧性能

运用TPO,XRD,BET,O2-TPD,H2-TPR,XPS等技术,研究了在CeO2中引入不同Mn含量对催化剂表面氧性质的影响,并重点探讨了吸附于氧空位上的原子吸附氧O-与催化碳烟燃烧活性的关联。结果表明:将Mn中引入CeO2后,MnOx-CeO2晶格中可形成较CeO2更多的氧空位,并有利于氧的活化和迁移,生成了较多原子吸附氧O-;MnOx(0.4)-CeO2在碳烟起燃温度区间有最多的原子吸附氧O-,其碳烟起燃活性最高,对应的起燃温度是346℃,比无催化剂时降低了111℃,比CeO2降低了35℃。     

Photochemical preparation of CdS hollow microspheres at room temperature and their use in visible-light photocatalysis

CdS hollow microspheres have been successfully prepared by a photochemical preparation technology at room temperature, using polystyrene latex particles as templates, CdSO₄ as cadmium source and Na₂S₂O₃ as both sulphur source and photo-initiator. The process involved the deposition of CdS nanoparticles on the surface of polystyrene latex particles under the irradiation of an 8 W UV lamp and the subsequent removal of the latex particles by dispersing in dichloromethane. Photochemical reactions at the sphere/solution interface should be responsible for the formation of hollow spheres. The as-prepared products were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Such hollow spheres could be used in photocatalysis and showed high photocatalytic activities in photodegradation of methyl blue (MB) in the presence of H₂O₂. The method is green, simple, universal and can be extended to prepare other sulphide and oxide hollow spheres.