表面等离子共振(SPR)——一种新型化学检测方法的原理

近年来,表面等离子共振(SPR)现象、由于在金属纳米材料研究以及在作为灵敏检测不同化学和生化物种信号的报告器方面有着特殊的应用价值,因而受到广泛的关注.本文较详细的介绍了表面等离子共振现象的形成机制,特别对如何利用本方法作为一种新型的物种检测报告器的有关问题做了较系统的讨论.     

基于纳米金粒子可视化分析检测的研究进展

基于纳米金粒子表面等离子共振性质发展起来的可视化分析,由于具有灵敏度高、可设计性强、分析过程快速等优点已被广泛地应用于各类目标分析物的检测,成为一种极具潜力的分析手段。本文综述了基于纳米金粒子表面等离子共振可视化分析检测的研究进展,并对其发展趋势进行了展望。     

帽状锑纳米粒子的制备及表面等离子共振特性的研究

采用热蒸发法在SiO₂自组装单层膜上制备了帽状锑纳米粒子,通过扫描电镜(SEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)和紫外-可见-近红外(UV-Vis-NIR)分光光度计对帽状复合纳米粒子的表面形貌、结构以及表面等离子共振特性进行了研究和表征。结果表明,制备的复合纳米粒子呈帽状,表面等离子共振峰具有明显的可调谐性,当二氧化硅粒径增大或锑帽层厚度增加时,等离子共振吸收峰位置红移。     

分子印迹表面等离子共振传感器在食品安全检测中的最新研究进展

分子印迹聚合物具有空间结构选择性高、稳定性好和制备过程简单等特点,结合表面等离子共振传感器,可用于分子间相互作用和结合特性的研究。随着石墨烯、量子点等纳米材料的出现和广泛应用,基于分子印迹技术的表面等离子共振传感器的灵敏度获得了改善,促进了该技术在食品安全检测领域的快速发展。该文基于分子印迹技术简要介绍了表面等离子共振传感器芯片的制备技术、分析体系及其优点,重点分析了国内外将分子印迹-表面等离子共振传感器用于食品安全检测的最新研究成果,阐释了分子印迹-表面等离子共振技术的优势,并展望了该技术在食品安全分析领域的发展趋势。     

表面等离子体共振技术在电化学反应过程研究中的应用

简述了表面等离子体共振(SPR)的基本原理,并综述了表面等离子体共振技术在电化学反应过程中的应用。SPR技术可以无需任何标记原位实时地检测分子间的相互作用,也可用于连续监测吸附/脱附和缔合/解离过程。表面等离子共振光谱(SPRS)与电化学技术结合可用来同时表征和处理电极/溶液的界面,在电化学掺杂/去掺杂过程、吸附/脱附反应的研究、痕量物质的检测、薄膜厚度、介电常数的测定等方面的应用已取得了很大的进展。     

帽状锡纳米粒子的制备及其表面等离子的共振特性

采用真空热蒸发法在SiO2自组装单层膜上沉积金属锡, 制备了帽状锡纳米结构, 通过扫描电镜(SEM)、原子力显微镜(AFM)、X射线衍射(XRD)仪和Cary 5000紫外-可见-近红外(UV-Vis-NIR)分光光度计对其表面形貌、结构以及光谱特性进行了研究和表征. 结果表明, 制备的复合纳米粒子呈帽状, 表面等离子共振峰位具有明显的可调谐性, 随二氧化硅粒径的增大或锡帽层厚度的增加, 表面等离子共振吸收峰向长波方向移动.     

基于β环糊精功能化金纳米棒光学探针检测多酚化合物

以β环糊精(β-CD)功能化金纳米棒为光学探针,基于β-CD对芒果苷、白杨素及瑞香素多酚化合物的包合作用,建立了一种检测疏水性多酚化合物的新方法。多酚化合物在体积分数10%的甲醇水溶液(pH 6.0)介质中,与β-CD功能化金纳米棒作用10 min,β-CD的包合作用使其富集到金纳米棒表面,从而引起金纳米棒表面等离子共振吸收光谱发生变化;以质谱等技术证明了β-CD对多酚化合物具有包合作用。随着多酚化合物浓度的增加,金纳米棒探针在约为700 nm处的等离子共振吸收峰随之线性下降,对芒果苷、白杨素和瑞香素的检出限分别为9.0×10-9,5.0×10-8,4.0×10-8mol/L,建立了一种可在水溶液中富集与检测疏水性多酚化合物的新方法。     

金纳米微粒作探针共振瑞利散射光谱法测定卡那霉素

在一种含柠檬酸盐的溶液中, 柠檬酸根阴离子自组装于带正电荷的金纳米微粒表面, 使金纳米微粒成为一种被柠檬酸根包裹的带负电荷的超分子化合物. 在pH 4.4～6.8的弱酸性介质中, 它可与质子化的卡那霉素(KANA)阳离子借静电引力、疏水作用力结合, 形成粒径更大的聚集体(平均粒径从12增至20 nm), 这种聚集体的形成在引起金纳米的等离子体吸收带明显红移(Δλ＝102 nm)的同时, 共振瑞利散射(RRS)显著增强并且倍频散射(FDS)和二级散射(SOS)等共振非线性散射也有较大的增强, 最大散射峰分别位于280 nm (RRS), 310 nm (FDS)和480 nm (SOS)处. 在适当条件下, 散射强度(ΔI)与卡那霉素的浓度成正比, 其中RRS法灵敏度最高, 因此金纳米微粒可作为测定卡那霉素的高灵敏RRS探针, 它对卡那霉素的检出限为10.52 ng•mL^－1, 方法有较好的选择性, 可用于血液中卡那霉素的测定, 文中还讨论了有关反应机理和RRS增强的原因.     

固定光路可变焦宽调角表面等离子共振成像装置

设计了一种折反式棱镜耦合单元, 用于简化表面等离子共振系统的角度调节操作, 并基于此单元构建了固定光路可变焦宽调角表面等离子共振成像装置. 该装置通过旋转折反式棱镜耦合单元即可实现角度调节, 调节范围可达40°~80°, 结合1~2倍的变焦成像系统, 可对1~4 cm²传感芯片成像, 且可分辨至少3600 Point/cm². 以蔗糖溶液为研究对象, 考察了该装置的灵敏度, 结果表明其灵敏度可达7×10^-6 RIU(Refractive index unit), 共振角与折射率的线性相关系数为0.99953. 将该装置用于研究抗牛血清白蛋白抗体与其它蛋白的实时相互作用, 所得结果与理论相符. 该表面等离子共振成像装置将在实时并行分析方面具有广阔的应用前景.     

Gels from a semifluorinated n-alkane in fluorinated solvents as a probe for intermolecular interactions

Diblock semifluorinated n-alkanes can form aggregates and gels in fluorinated solvents. We have investigated the thermal behavior of binary mixtures comprising F(CF₂)₈(CH₂)₁₆H and fluorinated solvents. The solvents were perfluorohexane, perfluoroheptane, perfluorooctane, perfluorooctyl bromide, perfluorodecalin, and perfluorotributylamine. The phase diagrams were used to calculate the activity coefficients of the two components and the main excess thermodynamic functions. The solubility and self-assembly behavior of F₈H₁₆ in the fluorinated solvents are related to the different solute–solvent dispersion interactions that depend on the polarizabilities and ionization potentials of the interacting species, and on the structural properties of the solvent.     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性;均苯四甲酸二酐;联苯四羧酸二酐;二羟基联苯胺;聚酰亚胺;聚苯并噁唑;耐热性     

HCOO在Cu(110)、Ag(110)和Au(110)表面的吸附

采用密度泛函理论(DFT)以及广义梯度近似方法(GGA)计算了甲酸根(HCOO)在Cu(110)、Ag(110)和Au(110)表面的吸附. 计算结果表明, 短桥位是最稳定的吸附位置, 计算的几何参数与以前的实验和计算结果吻合. 吸附热顺序为Cu(110)(-116 kJ·mol-1)>Ag(110)(-57 kJ·mol-1)>Au(110)(-27 kJ·mol-1), 与实验上甲酸根的分解温度相一致. 电子态密度分析表明, 吸附热顺序可以用吸附分子与金属d-带之间的Pauli 排斥来关联, 即排斥作用越大, 吸附越弱. 另外还从计算的吸附热数据以及实验上HCOO的分解温度估算了反应CO2+1/2H2→HCOO的活化能, 其大小顺序为Au(110)>Ag(110)>Cu(110).     

Transition metal complexes of the tripodal ligand 4-(2′-pyridylmethyl)-4-azaheptane-1,7-diamine. Crystal structures of [CuLCl]ClO4 and [NiL(MeCN)2](ClO4)2

The tripodal ligand 4-(2′-pyridylmthyl)-4-azaheptane-1,7-diamine has been prepared by reaction of 2-aminemethyl pyridine with acrylonitrile, followed by the reduction of the nitrile groups. Copper(II), nickel(II), zinc(II), cobalt(III) and chromium(III) complexes of the ligand have been prepared and characterized and the crystal structures of the complexes [CuLCl]ClO₄ and [NiL(MeCN)₂](ClO₄)₂ determined. The copper complex is five coordinate with approximate square pyramidal stereochemistry with the apical position occupied by a primary amine donor. The nickel complex is octahedral with the pyridine nitrogen donor lying trans to an acetonitrile ligand.     

SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES WITH AMPICILLIN

Abstract

The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]₂ × nH₂O (n = 1.5?3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.     

Magnetism of metal-nitroxide compounds involving bis-chelating imidazole and benzimidazole substituted nitronyl nitroxide free radicals

Coordination compounds based on imidazole and benzimidazole substituted nitronyl nitroxide radicals with transition metal ions and trivalent lanthanide ions are described from the perspective of their magnetic properties.For the transition metal compounds the crystal structures show various metal-nitroxide dimensionalities including mononuclear (0D), one-dimensional (1D) and two-dimensional (2D) complexes. The mononuclear complexes were isolated with most metal ions of the first transition series. One copper(II) complex shows a copper(II)-radical ferromagnetic coupling (J = +75 cm⁻¹) while for the other mononuclear compounds, mainly with manganese(II), the metal-radical interactions are antiferromagnetic. The one-dimensional and two-dimensional complexes are manganese(II) compounds which show canting effects leading to weak ferromagnetism.For the trivalent lanthanide ions [La(III), Gd(III) and Eu(III)], three series of mononuclear complexes were obtained in which the metal center is bound to four, two or one nitroxide radicals depending on the counter ions and ancillary ligands. Unexpectedly, in most gadolinium(III) complexes, the Gd(III)-radical interactions were found to be antiferromagnetic in contradiction with other foundings and previous theoretical models. In support to the magnetic studies, the optical properties of the lantanide complexes have also been investigated and are briefly described.     

New Complexes of Ditopic Ligands with “d” and/or “s” Metal Ions

Abstract

The asymmetric compartmental macrocycles containing one N₂O₂ or N₃O₂ Schiff base and one O₂O₃ or O₂O₄ crown-ether like chamber, have been obtained by condensation reaction of the formyl precursors 3,3′-(3-oxapentane-1, 5-diyldioxy) bis (2-hydroxybenzaldehyde) or 3,3′-(3,6-dioxaoctane-1,8-diyldioxy)-bis(2-hydroxybenzaldehyde) with ethyl ethylenediamine (H₂L_A, H₂L_C), 1,5-diamino-3-azamethylpentane(H₂L_B, H₂L_D), also in the presence of metal ions as templating agents. These ditopic ligands, with dissimilar coordination sites, have been designed and used for the selective complexation of “d” and/or “s” metal ions, respectively into the Schiff base and the crown ether chamber. The selectivity of these processes strongly depends on the size and on the donor atom sets of the sites. The possibility to obtain mononuclear M(L)·nH₂O (M = Ni²⁺, Cu²⁺, Co²⁺), Mn(L)(CH₃COO)·nH₂O or Na(L) and hetero-dinuclear MNa(L)(CH₃COO) (M = Ni²⁺, Cu²⁺, Co²⁺) and MnNa(L)(CH₃COO)₂·nH₂O complexes has been successfully tested. The ligands and complexes have been characterized by ir, nmr, mass spectrometry and magnetic susceptibility measurements.

Two of the ligands used for the preparation of the solid samples, i.e., to H₂L_A and H₂L_B, have been employed to study complexation reactions of Co(II) and Na(I) in solution. In order to obtain information on the ligand preorganization effect toward the complex stabilities, a simpler open chain parent compound of H₂L_B (H₂L_E) has been also prepared and studied. FT-IR spectra show that H₂L_A is unable to complex Na⁺ in DMSO while the complexation reactions of Na⁺ by H₂L_B and of Co²⁺ by H₂L_A take place with slow kinetics. Therefore, thermodynamic data have been obtained only for the systems Co²⁺/H₂L_B and Co²⁺/H₂L_E. The thermodynamic parameters obtained for the complexation reactions show that the pre-organization of the donor atoms in H₂L_B does not add a significant contribution to the stabilities of the complexes. Both H₂L_B and H₂L_E form in DMSO 1:1, 1:2 and 1:3 = M:L complexes with very similar stabilities and almost equal enthalpies of formation. Physico-chemical studies suggest besides that the slow reaction of Na⁺ with H₂L_B is probably due to the formation of a 1:1 complex where the metal cation, initially occupying the O₃ cage of the ligand, slowly binds also the oxygens of the phenolic moieties. Spectral and calorimetric data on solutions containing H₂L_B and different Co²⁺: Na⁺ ratios evidence that in DMSO no stable heterodinuclear complexes form when the neutral ligand is considered.     

具有聚集诱导发光性质的近红外荧光染料

聚集诱导发光(AIE)现象的发现为解决传统有机荧光分子在高浓度和聚集形态下存在的荧光猝灭问题提供了最佳方案,并实现了在光电器件、化学传感、生物成像和靶向治疗等众多领域的广泛应用。随着对AIE发光机理研究的不断深入,AIE分子体系得到了极大的扩展。其中,一类具有给体-受体结构的AIE分子能够显著降低分子能隙,使发光分子波长从可见光区(400~700 nm)延伸到近红外(NIR)区(700~1700 nm)。由于NIR发光分子在生物医学领域中的独特优势,其已成为目前AIE研究的热点。随着对NIR分子设计及应用的不断探索,附加不同功能且发光波长更长的AIE分子也被开发出来了,并实现了对生物体特定组织的NIR荧光成像、光声成像、光动力治疗和光热治疗等。本文总结了近年来具有AIE性能的NIR荧光分子的结构及其在生物医学领域的相关应用。     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.     

Spectrophotometric study of Cd(II), Pb(II), Hg(II) and Zn(II) complexes with 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin

The reaction of 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP) with Cd(II), Pb(II), Hg(II) and Zn(II) was studied spectrophotometrically and kinetics, equilibrium constants as well as photodecomposition of complexes were determined. It was verified that these metal ions with large radius accelerate the incorporation reaction of zinc into TCPP. On the basis of the mechanism and kinetics of this reaction, a sensitive method for the spectrophotometric determination of trace amounts of Zn(II) has been developed. The molar absorptivity of examined Zn-TCPP complex and Sandell's sensitivity at 423 nm were 3.5×10⁵ M⁻¹ cm⁻¹ and 18.3 ng cm⁻². The detection limit for the recommended procedure was 1.4×10⁻⁹ M (0.9 ng ml⁻¹) and precision in range 20-100 ng ml⁻¹ not exceeds 2.7% RSD. The proposed method applied for zinc determination in natural waters and nutritional supplement was compared with AAS results and declared value.