A Novel Potassium Complex Based on the Taurine-salicylaldehyde Schiff Base:Synthesis, Crystal Structure and Spectroscopy

A novel two-dimensional self-assembly network formulated as [K(TSSB)]n (TSSB= taurine-salicylaldehyde Schiff base) has been synthesized via the reaction of salicylaldehyde with taurine at the presence of potassium hydroxide in water-methanol solution,and was structurally characterized by elemental analysis,IR,UV-VIS spectra and X-ray diffraction.It crystallizes in the monoclinic system,space group P21/c with a=20.245(3),b=7.2905(9),c=7.5458(10),β= 94.1920(10)o,V=1110.8(2)3,Mr=267.34,Z=4,Dc=1.599 g/cm3,μ(MoKα)=0.663 mm-1 and F(000)=552.The units of K[TSSB] are linked into a one-dimensional double chain structure via the sulfonic groups from the taurine-salicylaldelyde Schiff base,and such chains are further extended through O-K-O bond interactions resulting in a two-dimensional supramolecular architecture.In the complex,the K(I) ion displays a slightly distorted dodecahedral geometry with an eight-coordination number.     

The use of plasma actuators for bluff body broadband noise control

Experiments were conducted using plasma actuators to control broadband noise generated by a bluff body flow. The motivation behind the study was to explore the potential of plasma actuators to reduce landing gear noise during approach phase of an aircraft. The control effectiveness of both dielectric barrier discharge and sliding discharge plasma actuators were tested in laboratory environment, using a representative bluff body consisting of a circular cylinder and an oblique strut. Noise measurements were taken in an anechoic chamber using a phased microphone array and far-field microphones. Results showed that the upstream directed plasma forcing, located at ±90 deg on the upstream cylinder with respect to the approaching flow, could effectively attenuate the broadband noise radiated from the wake flow interaction with the downstream strut. With the same AC electrical power consumption, the sliding discharge with additional DC voltage was found to be more effective due to its elongated plasma distribution and higher induced flow momentum. Measurements using particle image velocimetry suggested that the flow speed impinging on the downstream strut was reduced by the upstream plasma forcing, contributing to the reduced noise.     

无机化学实验课程的优化改革尝试

就大一无机化学实验过程中近年来出现的问题提出了有针对性的解决方法。主要从优化实验内容、教学模式、实验减污再用等方面进行了探索。     

气相色谱-质谱法同时快速测定血清中5种剧毒灭鼠剂

建立了同时快速测定血清样品中毒鼠强、氟乙酰胺、氟乙酸钠、甘氟Ⅰ与甘氟Ⅱ 5种灭鼠剂的气相色谱-质谱联用法。在pH 2.0条件下,以N,N-二乙基对苯二胺为衍生剂,N,N'-二环己基碳二亚胺为催化剂,氟乙酸钠在室温下振荡衍生5 min,衍生物与毒鼠强、氟乙酰胺、甘氟Ⅰ、甘氟Ⅱ一并被乙酸乙酯萃取,经50 ℃下氮吹浓缩后用气相色谱-质谱同时测定,采用选择离子监测(SIM)模式,基质标准外标法定量。方法选用SLB-IL59离子液体毛细管柱(30 m×0.25 mm×0.20 μm,最高温度:300 ℃),流速1.0 mL/min,经程序升温在15 min内成功地分离了5种灭鼠剂。结果显示,血清中氟乙酰胺的线性范围为0.02~2.0 mg/L,毒鼠强的线性范围为0.02~10 mg/L,其他目标物的线性范围为0.01~1.0 mg/L;检出限为0.001~0.002 mg/L (S/N=3),相关系数R²>0.995。在3个加标水平下,方法加标回收率介于84.0%和110.0%之间,相对标准偏差(n=6)介于2.9%和7.5%之间。方法操作简便、准确,灵敏度高,适于中毒病人的快速诊断检测。     

酶标分析仪波长标准物质的研制

以硫化锌为高折射材料和冰晶石为低反射材料,利用真空镀膜技术、光学极值法检测膜厚技术镀制了窄带全介质干涉滤光片,K9玻璃为薄膜保护层,采用切割、粗磨、精磨、抛光、镀膜等光学工艺制得酶标分析仪波长标准物质,经均匀性、稳定性考核合格后,由紫外可见近红外分光光度计标准装置对标准物质定值。研制的酶标分析仪波长标准物质定制结果扩展不确定度为0.7 nm(k=2),使用方便,量值准确、稳定,技术指标满足酶标分析仪波长示值误差及重复性检定/校准工作的需要。     

Are Triphenylamine‐Functionalized or Carbazole‐Functionalized Iridium Complexes the More Effective Phosphorescent Materials? A Theoretical Perspective

The ground and excited states, charge injection/transport, and phosphorescence properties of eleven carbazole‐ and triphenylamine‐functionalized Ir^III complexes were investigated by using the DFT method. By analyzing the spin–orbit coupling (SOC) matrix elements, radiative decay rate constants k_r, and the electronic structures and energies at the ${{\rm{S}}_{\rm{0}}^{{\rm{opt}}} }$ and ${{\rm{T}}_{\rm{1}}^{{\rm{opt}}} }$ states, it was possible to rationalize the order of the experimental phosphorescence quantum yields of a series of Ir^III complexes and to predict that [Ir(Nph‐2‐Cz‐tz)₃] has a higher phosphorescence quantum yield than [Ir(TPA‐tz)₃] (TPA=triphenylamine, tz=thiazolyl, Cz=carbazole, Nph=N‐phenyl). Carbazole‐functionalized Ir^III complexes were shown to be efficient phosphorescent materials that have not only fast but also balanced electron/hole‐transport performance as well as high phosphorescence quantum yields. The phosphorescence emission spectra can be modulated by modifying or replacing a pyridyl substituent.     

Kinetic Assay of the Michael Addition‐Like Thiol–Ene Reaction and Insight into Protein Bioconjugation

The chemical modification of proteins is a valuable technique in understanding the functions, interactions, and dynamics of proteins. Reactivity and selectivity are key issues in current chemical modification of proteins. The Michael addition‐like thiol–ene reaction is a useful tool that can be used to tag proteins with high selectivity for the solvent‐exposed thiol groups of proteins. To obtain insight into the bioconjugation of proteins with this method, a kinetic analysis was performed. New vinyl‐substituted pyridine derivatives were designed and synthesized. The reactivity of these vinyl tags with L ‐cysteine was evaluated by UV absorption and high‐resolution NMR spectroscopy. The results show that protonation of pyridine plays a key role in the overall reaction rates. The kinetic parameters were assessed in protein modification. The different reactivities of these vinyl tags with solvent‐exposed cysteine is valuable information in the selective labeling of proteins with multiple functional groups.     

Well‐Defined Metal–Organic Framework Hollow Nanocages

Metal–organic frameworks (MOFs) have demonstrated great potentials in a variety of important applications. To enhance the inherent properties and endow materials with multifunctionality, the rational design and synthesis of MOFs with nanoscale porosity and hollow feature is highly desired and remains a great challenge. In this work, the formation of a series of well‐defined MOF (MOF‐5, Fe^II‐MOF‐5, Fe^III‐MOF‐5) hollow nanocages by a facile solvothermal method, without any additional supporting template is reported. A surface‐energy‐driven mechanism may be responsible for the formation of hollow nanocages. The addition of pre‐synthesized poly(vinylpyrrolidone)‐ (PVP) capped noble‐metal nanoparticles into the synthetic system of MOF hollow nanocages yields the yolk–shell noble metal@MOF nanostructures. The present strategy to fabricate hollow and yolk–shell nanostructures is expected to open up exciting opportunities for developing a novel class of inorganic–organic hybrid functional nanomaterials.     

Quick and selective extraction of Z‐ligustilide from Angelica sinensis using magnetic multiwalled carbon nanotubes

A facile and highly efficient magnetic solid‐phase extraction method has been developed for Z‐ligustilide, the major therapeutic agent in Angelica sinensis. The solid‐phase adsorbent material used was prepared by conjugating carbon nanotubes with magnetic Fe₃O₄ nanoparticles via a hydrothermal reaction. The magnetic material showed a high affinity toward Z‐ligustilide due to the π–π stacking interaction between the carbon nanotubes and Z‐ligustilide, allowing a quick and selective exaction of Z‐ligustilide from complex sample matrices. Factors influencing the magnetic solid‐phase extraction such as the amount of the added adsorbent, adsorption and desorption time, and desorption solvent, were investigated. Due to its high extraction efficiency, this method was proved highly useful for sample cleanup/enrichment in quantitative high‐performance liquid chromatography analysis. The proposed method had a linear calibration curve (R² = 0.9983) over the concentration between 4 ng/mL and 200 μg/mL Z‐ligustilide. The accuracy of the method was determined by the recovery, which was from 92.07 to 104.02%, with the relative standard deviations >4.51%.     

Template‐Free Synthesis of Core–Shell TiO2 Microspheres Covered with High‐Energy {116}‐Facet‐Exposed N‐Doped Nanosheets and Enhanced Photocatalytic Activity under Visible Light

Core–shell TiO₂ microspheres possess a unique structure and interesting properties, and therefore, they have received much attention. The high‐energy facets of TiO₂ also are being widely studied for the high photocatalytic activities they are associated with. However, the synthesis of the core–shell structure is difficult to achieve and requires multiple‐steps and/or is expensive. Hydrofluoric acid (HF), which is highly corrosive, is usually used in the controlling high‐energy facet production. Therefore, it is still a significant challenge to develop low‐temperature, template‐free, shape‐controlled, and relative green self‐assembly routes for the formation of core–shell‐structured TiO₂ microspheres with high‐energy facets. Here, we report a template‐ and hydrofluoric acid free solvothermal self‐assembly approach to synthesize core–shell TiO₂ microspheres covered with high‐energy {116}‐facet‐exposed nanosheets, an approach in which 1,4‐butanediamine plays a key role in the formation of nanosheets with exposed {116} facets and the doping of nitrogen in situ. In the structure, nanoparticle aggregates and nanosheets with {116} high‐energy facets exposed act as core and shell, respectively. The photocatalytic activity for degradation of 2,4,6‐tribromophenol and Rhodamine B under visible irradiation and UV/Vis irradiation has been examined, and improved photocatalytic activity under visible light owing to the hierarchical core–shell structure, {116}‐plane‐oriented nanosheets, in situ N doping, and large surface areas has been found.