OTS自组装单分子膜在玻璃表面形成程的AFM研究

运用原子力显微镜研究了十八烷基三氯硅烷在玻璃表面自组装形成单分子膜的过程.通过对样品表面的显微图像、表面平均粗糙度及前进接触角的测量分析,揭示了自组装单分子膜在玻璃表面的生长规律,并探索反应初期玻璃表面的吸附特点.     

分子自组装单层膜的表面浸润性研究现状和展望

立足于分子自组装单层膜的制备及结构, 讨论了分子自组装单层膜的头基基团与基底的作用机理、 主链与环境的温度依赖关系, 特别是其端基基团的化学性质及构象对表面浸润行为的影响. 重点讨论了分子自组装单层膜的端甲基基团对表面能的贡献、 极性端基基团与水分子之间的相互作用以及自组装单层膜表面的分子尺寸粗糙度对表面浸润的影响. 最后, 基于理论和实验基础对以上问题提出新的认知与看法, 并对未来该领域发展的机遇与挑战进行了展望.     

3-巯基丙酸自组装单分子膜的研究进展

自组装单层或单分子膜(Self-assembled monolayers)的研究十分活跃,尤其是硫-金体系的单层研究更是得到科学家们的青睐。3-巯基丙酸由于可以在金基底形成稳定有序的二维自组装单分子膜,从而显示出独特的结构和表面性质。该文着重从膜的制备、膜内分子的结构、单层膜的性质以及应用等方面综述金基底上3-巯基丙酸自组装单分子膜的研究进展,并对其前景进行了展望。     

席夫碱自组装单分子膜的电化学行为

利用自组装技术将席夫碱硫醇衍生物在金表面形成自组装单分子膜,并初步研究了此自组装单分子膜的电化学行为,发现该席夫碱分子在0.1 mol•L－1的KCl溶液中具有电化学不可逆氧化还原行为，且随着自组装时间的增加表观电极反应速率常数值显著减小,最后减小为0,并对此进行了解释.     

乙二胺改性的玻璃基片上C60自组装薄膜的制备及其光致发光

利用Ｃ６０与乙二胺改性的普通玻璃表面进行加成反应，得到一种新的Ｃ６０自组装单层膜；在自组装单层膜的基础上，利用Ｃ６０与乙二胺反应形成自组装双层膜．通过Ｘ光电子能谱、激光解吸电离飞行时间质谱等手段证实在乙二胺改性的普通玻璃表面上存在通过化学键合的Ｃ６０自组装单层和双层膜．并对其光致发光性质进行了初步研究，发现在６８０ｎｍ附近存在一个与Ｃ６０不同的宽的光致发光峰     

乙二胺改性的玻璃基片上C60自组装薄膜的制备及光致发光

利用Ｃ６０与乙二胺改性的普通玻璃表面进行加成反应,得到一种新的Ｃ６０自组装单层膜;在自组装单层膜的基础上,利用Ｃ６０与乙二胺反应形成自组装双层膜。通过Ｘ光电子能谱、激光解吸电离飞行时间质说等手段证实在乙二胺改性的普通玻璃表面上存在通过化学键合的Ｃ６０自且装单层和双层膜。并对共光致发光性质进行了初步研究,发现在６８０ｎｍ附近存在一个与Ｃ６０不同的宽的光致发光峰。     

自组装单分子膜及其表征方法

自组装单分子膜的研究是近年来十分活跃的研究领域. 随着膜的应用领域的拓展 ,对膜的表征方法不断提出新的要求.本文综述了自组装单分子膜体系的类型和基底表面的 处理方法,着重从电化学、谱学、显微学以及表面润湿性等方面综述了近几年来自组装单分子膜的表征方法研究进展, 并对其发展前景作了展望.     

偶氮苯衍生物自组装膜的表征及组装动力学

报导了4-正辛基-4′-（3－巯基丙氧基）偶氮苯（简称C8AzoC3）自组装膜（Self-AssembledMonolnyersSAMs）的表征及其自组装成膜动力学，接触角滴定、原子力显微镜（AFM）及电化学的实验结果表明，C8AzoC3分子在金表面自组装形成致密有序的流水性单分子膜，并且在电极上没有明显的电化学响应．通过控制组装时间，考察了偶氮苯自组装形成单分子膜的动力学过程，从接触角和电化学数据得到组装过程的速率常数kad为（1.2±0.2）×103mol-1·dm3·s－1；依据不同组装时间形成的自组装膜的特征循环伏安行为，提出了C8AzoC3分子在金表面自组装过程的动态模型．     

以OTS自组装单分子膜为探针研究TiO2液相空穴氧化机理

通过引入十八烷基三氯硅烷(OTS)自组装单分子膜作为氧化反应的探针, 在排除反应物的吸附和扩散的条件下研究溶胶-凝胶制备的TiO2薄膜表面光催化空穴氧化初始过程. 研究结果表明, 在紫外光照下, 水溶液中OTS部分覆盖的TiO2表面能够很快从憎水变成亲水. 存在空穴捕获剂后, TiO2表面OTS自组装单分子膜碳链的脱除受到明显抑制, 水接触角随光照时间变化非常小; 而水中羟基自由基捕获剂或者F-的存在则对TiO2表面OTS自组装单分子膜碳链的脱除几乎无影响. 这表明, 空穴氧化在TiO2表面OTS自组装单分子膜碳链的脱除中占主要地位.     

苝四羧酸自组装单分子膜的制备及其光电转换性质研究

通过共价键连接的方式在亲水性基底上制备了刚性功能分子3,4,9,10- NFDA1 四羧酸的自组装单分子膜,利用接解角、紫外-可见光谱、电化学循环伏安等方法对所制备的NFDA1 四羧酸自组装膜进行了表征,并初步研究了该自组装膜在ITO电极表面光电转换性质.     

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     

Studies on the Formation of Catalytically Active PGM Nanoparticles from Model Solutions as a Basis for the Recycling of Spent Catalysts

The paper presents basic studies on the precipitation of platinum, palladium, rhodium, and ruthenium nanoparticles from model acidic solutions using sodium borohydride, ascorbic acid, and sodium formate as reducing agents and polyvinylpyrrolidone as a stabilizing agent. The size of the obtained PGM particles after precipitation with NaBH₄ solution does not exceed 55 nm. NaBH₄ is an efficient reducer; the precipitation yields for Pt, Pd, Ru, Rh are 75, 90, 65 and 85%, respectively. By precipitation with ascorbic acid, it is possible to efficiently separate Pt, Rh, and Ru from Pd from the two-component mixtures. The obtained Pt, Pd, and Rh precipitates have the catalytic ability of the catalytic reaction of p-nitrophenol to p-aminophenol. The morphological characteristic of the PGM precipitates was analyzed by AFM, SEM-EDS, and TEM.     

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.     

Direct Quantitation of Phytocannabinoids by One-Dimensional 1H qNMR and Two-Dimensional 1H-1H COSY qNMR in Complex Natural Mixtures

The widespread use of phytocannabinoids or cannabis extracts as ingredients in numerous types of products, in combination with the legal restrictions on THC content, has created a need for the development of new, rapid, and universal analytical methods for their quantitation that ideally could be applied without separation and standards. Based on previously described qNMR studies, we developed an expanded ¹H qNMR method and a novel 2D-COSY qNMR method for the rapid quantitation of ten major phytocannabinoids in cannabis plant extracts and cannabis-based products. The ¹H qNMR method was successfully developed for the quantitation of cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabichromene (CBC), cannabichromenic acid (CBCA), cannabigerol (CBG), cannabigerolic acid (CBGA), Δ9-tetrahydrocannabinol (Δ9-THC), Δ9-tetrahydrocannabinolic acid (Δ9-THCA), Δ8-tetrahydrocannabinol (Δ8-THC), cannabielsoin (CBE), and cannabidivarin (CBDV). Moreover, cannabidivarinic acid (CBDVA) and Δ9-tetrahydrocannabivarinic acid (Δ9-THCVA) can be distinguished from CBDA and Δ9-THCA respectively, while cannabigerovarin (CBGV) and Δ8-tetrahydrocannabivarin (Δ8-THCV) present the same ¹H-spectra as CBG and Δ8-THC, respectively. The COSY qNMR method was applied for the quantitation of CBD, CBDA, CBN, CBG/CBGA, and THC/THCA. The two methods were applied for the analysis of hemp plants; cannabis extracts; edible cannabis medium-chain triglycerides (MCT); and hemp seed oils and cosmetic products with cannabinoids. The ¹H-NMR method does not require the use of reference compounds, and it requires only a short time for analysis. However, complex extracts in ¹H-NMR may have a lot of signals, and quantitation with this method is often hampered by peak overlap, with 2D NMR providing a solution to this obstacle. The most important advantage of the COSY NMR quantitation method was the determination of the legality of cannabis plants, extracts, and edible oils based on their THC/THCA content, particularly in the cases of some samples for which the determination of THC/THCA content by ¹H qNMR was not feasible.     

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.     

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.     

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...