Tuning of particle plasmon resonances in binary dielectric medium

Using light scattering spectroscopy, I demonstrate an approach to tune particle plasmon resonance in a binary dielectric media where silver nano-rods are embedded partially both in Anodic Aluminum Oxide (AAO) matrix and in air. A systematic experimental study under a controlled variation of the degree of embedding of nano-rods in AAO matrix has been presented. Experimental results have been interpreted based on the Drude model. Finite Difference Time Domain (FDTD) method has been employed to calculate the nature of the silver nano-rod resonance at the experimental conditions. Both the simulation results and theory corroborate the experimental findings.     

对磺酸基苯基亚甲基若丹宁固相萃取光度法测定银

研究了对磺酸基苯基亚甲基若丹宁(SBDR)与银的显色反应,在pH为2.6的柠檬酸-氢氧化钠缓冲介质中,吐温-80存在下, SBDR与银反应生成2∶1稳定络合物,该络合物可用Waters Porapak Sep-Park固相萃取小柱富集,用乙醇(含5％乙酸)溶液洗脱后用光度法测定,在乙醇介质中λ_max＝520 nm,摩尔吸光吸数ε＝7.53×104 L·mol-1·cm-1。银含量在0～1.2 μg·(25 mL)-1内符合比尔定律,方法用于环境水样中银含量的测定,结果令人满意。     

3-氨基-5-巯基-1,2,4-三唑与Ag(I)配位作用的密度泛函理论研究

采用密度泛函理论B3LYP方法研究3-氨基-5-巯基-1,2,4-三唑与Ag(I)的配位特点.计算结果显示,ad-L配体配位能力显著高于中性配体L,其中SN配位模式稳定化能高于中性配体约443.8kJ/mol,且N2模式稳定化能高于中性配体约336.8 kJ/mol;而p-L配体相互作用能和稳定化能均为负值.自然键轨道(NBO)分析显示配体与Ag(I)间存在较强轨道作用.静电势分析发现,L配体最负静电势出现在N1、N2原子周围,因此N1、N2位点更易与Ag(I)配位; ad-L配体静电势为负,因此与Ag(I)作用增强,而质子化的配体p-L静电势为正,因此不易与Ag(I)配位.     

壳聚糖富集-火焰原子吸收法测定痕量银

研究了天然高分子吸附剂-壳聚糖对银离子的吸附行为以及在不同pH值、干扰离子存在时对壳聚糖吸附银离子的影响,通过选择最佳吸附条件,建立了壳聚糖富集-火焰原子吸收法测定银的方法。当溶液pH 6.0、流速为1 mL·min-1时,吸附率最高,达96.7%,静态饱和吸附量为97.8 mg·g-1。用1 mol·L-1 H₂SO₄作为洗脱剂,洗脱效果最好。壳聚糖不吸附K+,Na+,Ca2+,Mg2+,Mn2+,富集时可与被测银离子分离,不干扰测定。100 mg·mL-1的Al3+,Cr3+,80 mg·mL-1的Ni2+,Cu2+,Pb2+,Zn2+虽然可被壳聚糖吸附, 但不干扰测定。用此方法对实验室含银(1.83 μg·mL-1)废水中的Ag进行测定,回收率为94.3%。     

Studies on the Evolution of Silver Nanoparticles in Micelle by UV-Photoactivation

Ultraviolet (UV) photoirradiation of Ag(I) compounds in the presence of an aqueous Triton X-100 solution has been exploited for the first time to prepare reproducible yellow silver hydrosol. The evolution of nanosized silver particles has been examined critically under the influence of different anions/ligands. Hence, time dependent evolution of silver hydrosol from different silver compounds in micelle via photochemical reduction is observed. Anions/ligands of precursor salts have been found to show profound influence (due to electron scavenging property, solubility, stability etc.) on the evolution route and efficiency of photochemical reduction of Ag(I) to Ag(O) in micelle and thereby classification of silver compounds becomes possible. Kinetic results reveal that the formation of silver particles proceeds via autocatalytic growth mechanism. The observed variation in rate constant values for the evolution of nanoparticles from different silver compounds have been explained in terms of available thermodynamic and kinetic parameters. Nucleophile induced dissolution and reversible photogeneration of zerovalent silver particles have been investigated under ambient condition.     

The photoelectron spectra of gaseous silver halides

Ionization potentials have been determined for gaseous AgCl, AgBr and AgI using He(I) photoelectron spectroscopy. The solids were vaporized directly into the photon beam from a heated substrate. Molecular orbitals were assigned to observed spectral bands based upon simple molecular orbital arguments, band intensity relationships and observed spin—orbital splitting. The spectra of the gaseous silver halides are more complex than those of other diatomic halides as a result of Ag(d)-X(π) interactions which occur in these molecules.     

电感耦合等离子体发射光谱法测定银基钎料中银,铜,锌和镉的含量

本文叙述用电感耦合等离子体发射光谱法直接测定银基钎中角，铜，锌和镉，考察了光谱干扰和酸度的影响，在优化的操作条件下可以获得满意的分析结果，相对标准偏差４～７％，加标回收率为９４％～１０５％，该方法简便可靠，适合角基钎料的多元素同时测定。     

碘-碱性艳蓝BO体系分光光度法测定痕量银的研究

研究了萘基二苯甲烷染料和染料与[AgI₂]-缔合物光谱和分析性能。提出了一种基于在H₃PO₄～NaH₂PO₄缓冲溶液中碱性艳蓝BO与[AgI₂]-反应生成蓝色缔合物,采用分光光度法测定痕量银。其最大吸收波长为574 nm,表观摩尔吸光系数7.25×104 L·mol-1·cm-1 ,线性范围4～250 μg·L-1,回收率97.0%～98.3%,相对标准偏差2.7%。此方法可应用于水体中痕量银的测定。     

火焰原子吸收光谱法测定含卤素金属原子簇化合物中银

本文介绍了火焰原子吸收光谱法测定含卤素金属原子簇化合物中银。研究了样品制备方法及常见共存元素干扰。平均回收率100%(99-101%),相对标准偏差<1%。用本法测定含卤素金属原子簇化合物中银,获得满意的结果。     

固相萃取-钨丝电热原子吸收光谱分析法测定水样中的银

建立了基于固相萃取和便携式钨丝电热原子吸收光谱仪的测定环境水样中痕量银的新方法.样品流经以硅胶作为吸附剂的固相萃取小柱,银离子被吸附于柱上,用硫脲和硝酸混合液将其洗脱,洗脱液用便携式钨丝电热原子吸收光谱仪进行检测.考察了各种实验参数及共存离子对测定的干扰情况,最终选择样品pH值为6.0、流速为4.0 mL·min-1;...     

A New Highly Selective Fluorescent Silver Probe

We have synthesized 3,3,7,7-tetra[N-ethyl-N-benzyl(acetamide)-2-oxymethyl]-5- oxanonane (EBAOO) and its terbium complex. The crystal structures of the complex were determined: [Tb(EBAOO)](2)[Tb(NO(3))(5)](3).H(2)O, Orthorhombic, a=40.722 (6) A, b=18.418 (3) A, c=20.496 (3) A. In the structure, the rare earth ion satisfies nine coordination. The geometry of the nine-coordinate polyhedron is discussed in terms of the dihedral angle and the mean plane. The luminescence of the complex is noticeably enhanced upon complexation with Ag(+), which is due to the suppression of photoinduced electron transfer (PET) process. Therefore, the terbium complex can be used as a selective fluorescent silver probe.     

Density functional theory study on antiferromagnetic interactions in a silver (I) complex of nitronyl nitroxide

A one-dimensional (1D) silver (I) complex of nitronyl nitroxide with fairly strong antiferromagnetic interaction, in which the metal ions are diamagnetic, is investigated by means of the ab initio crystal orbital method based on the density functional theory. The calculated values of the magnetic coupling constant (J) are close to the experimental measured J value in the periodic system. The magneto-structural correlation reveals that the existence of an antiferromagnetic coupling pathway along nitronyl nitroxide units via silver (I) ion in this system. The spin population distribution also shows the existence of spin delocalization along the ONCNO–Ag–ONCNO, which affords a rational interpretation for the antiferromagnetic interaction mechanism.     

A stable ‘sandwich’ system of Surface‐Enhanced Resonance Raman Scattering for the analysis of β‐carotenes in a photosynthetic pigment‐protein complex

In plants, Photosystem I (PSI) is composed of a core complex and a membrane‐associated antenna complex light‐harvesting complex I that captures light and funnels its energy to the core complex. To obtain Raman structural information on β‐carotenes embedded in the PSI core complex, a ‘sandwich’ system of roughened silver slice: target protein complexes: single silver nanoparticles was fabricated for Surface‐Enhanced Resonance Raman Scattering (SERRS) measurements. This study provided a method to overcome spectral irreproducibility, which is the main drawback of Surface‐Enhanced Raman Scattering/SERRS‐based studies. The Raman spectra of β‐carotenes embedded in the PSI core complex can be obtained at very low sample concentrations (1–5 µg Chl/ml) and high signal/noise ratios. The β‐carotenes in the spinach PSI core complex were predominantly all‐trans configuration. The membrane protein‐mediated adsorption of silver nanoparticles induced the uniform distribution of a large number of single nanoparticles, which contributed to achieving highly reproducible SERRS spectra. This study is the first to apply single silver nanoparticle‐based SERRS analysis in membrane proteins. Copyright © 2013 John Wiley & Sons, Ltd.     

铋化物发光玻璃中银表面等离激元对铒离子的发光增强作用

局域表面等离激元可以由自由空间的光直接激发,这也是局域表面等离激元的优点所在。研究铋化物发光玻璃中纳米银颗粒的表面等离激元对铒离子发光的增强效应、进一步的提高铋化物发光玻璃中铒离子的发光性能很有意义。首先,测量了(A)Er 3+(0.5%)Ag(0.5%):铋化物发光玻璃与(B)Er 3+(0.5%):铋化物发光玻璃样品的吸收谱,发现(A)Er 3+(0.5%)Ag(0.5%):铋化物发光玻璃在约600.0 nm处有一个较弱的宽的银表面等离激元共振吸收峰。同时发现两者都有典型的铒离子的吸收峰,它们的吸收几乎完全一样:在波峰形状、峰值强度和峰值波长等方面都很相近。测量了(A)Er 3+(0.5%)Ag(0.5%):铋化物发光玻璃和(B)Er 3+(0.5%):铋化物发光玻璃样品的激发谱,发现有位于379.0,406.0,451.0,488.0和520.5 nm的5个550.0 nm可见光的可见激发谱峰,和位于379.0,406.5,451.0,488.5,520.5,544.0,651.5和798.0 nm的8个1531.0 nm红外光的红外激发谱峰,容易指认出依次为Er 3+的4I 15/2→4G 11/2,4I 15/2→2H 9/2,4I 15/2→(4F 3/2,4F 5/2),4I 15/2→4F 7/2,4I 15/2→2H 11/2,4I 15/2→4S 3/2,4I 15/2→4F 9/2和4I 15/2→4I 9/2跃迁的吸收峰,通过测量发现(A)Er 3+(0.5%)Ag(0.5%):铋化物发光玻璃相对于(B)Er 3+(0.5%):铋化物发光玻璃样品的可见和红外激发谱的最大增强依次分别是238%和133%。最后,测量了它们的发光谱,发现有位于534.0,547.5和658.5 nm的三组可见发光峰,容易指认出依次为Er 3+的2H 11/2→4I 15/2,4S 3/2→4I 15/2,4F 9/2→4I 15/2荧光跃迁。还发现红外发光峰位于978.0和1531.0 nm,依次为Er 3+的4I 11/2→4I 15/2和4I 13/2→4I 15/2的荧光跃迁。通过测量发现(A)Er 3+(0.5%)Ag(0.5%):铋化物发光玻璃相对于(B)Er 3+(0.5%):铋化物发光玻璃样品的可见和红外发光谱的最大增强依次分别是215%和138%。对于银表面等离激元增强铒离子发光的机理,认为主要为纳米银颗粒的局域表面等离激元共振,造成金属纳米结构附近产生的局域电场的强度要远大于入射光的电场强度,从而导致了金属纳米结构对入射光产生强烈的吸收和散射,进而导致了荧光的增强;即局域表面等离子体共振局域场的场增强效应。     

电解法制备纳米银溶胶及其SERS活性研究

分别用柠檬酸三钠溶液、硝酸银和聚乙烯醇混合液作为电解液,用银棒作为电极,加上7 V直流电压,通电1 h,用电解方法得到了纳米银溶胶。为测试该纳米银溶胶是否具有表面增强拉曼散射1(SERS)活性,选用了阳离子型分子碱性品红(Fuchsine basic)、亚甲基蓝(Methylene blue),阴离子型分子苯甲酸(Benzoic acid),甲基橙(Methyl orange)、中性分子吖啶橙(Alcidine orange)、苏丹红(Sudan red)作为测试分子,进行SERS研究,结果发现用两种电解液制备的纳米银都具有很强的SERS活性,但用硝酸银和聚乙烯醇混合液作为电解液制备的纳米银溶胶具有更广泛的SERS 活性。在该方法制备的纳米银上,得到了在常规方法制备的胶态纳米银上及用柠檬酸三钠溶液作为电解液制备的纳米银上得不到的甲基橙分子的SERS谱,对可能的原因进行了讨论。     

Dielectric properties of an ytterbium-based nematic liquid-crystal complex

The dielectric properties of an yttrium-based paramagnetic thermotropic nematic liquid-crystal complex have been studied. The conditions for the measurement of the magnitude and sign of the dielectric anisotropy of the mesophase have been determined. The relaxation of the components of the relative permittivity of a macroscopically homogeneously oriented sample has been observed. A high polarity of the metallomesogenic complex has been revealed.     

振动光谱法研究γ—球蛋白同银（Ⅰ）离子的作用

和Ｒａｍａｎ和ＦＴＩＲ光谱法研究了γ－球蛋白同银（Ｉ）离子的相互作用，结果表明，γ－球蛋白表面的氨基酸残基可同银（Ⅰ）离子反应，生成２或４配位的物种。其振动光谱在酰胺带区域呈现明显差异。研究了在恒定的加热温度下不同反应时间对振动Ｒａｍａｎ光谱的影响，结果表明，Ｒａｍａｎ光谱强度在１５ｍｉｎ左右有最大值，当时间超过１５ｍｉｎ后，物种中的银了子被还原为单质银。     

Modeling and Calculation of the Dynamics of Spectra with Allowance for Isomerization of Complex Molecules

A semiempirical parametric method for modeling of dynamic (time-resolved) electron-vibrational spectra of complex molecules with allowance for isomer-isomer transformations is proposed. It is based on the method developed earlier for construction of three-dimensional spectra of complex molecules without regard for isomer-isomer transformations. All the matrix elements necessary for calculation of spectra can be determined by the methods developed earlier. The time dependence of the population of a large number of vibronic levels has been determined using the iteration numerical method of integrating kinetic equations. Handy computational algorithms and a specialized software for a personal computer have been developed. The computer experiments conducted have shown that the method proposed can be used for modeling of dynamic spectra of complex molecules with allowance for their isomer-isomer transformations in the real-time scale.     

On the Fluorescence of Luminol in a Silver Nanoparticles Complex

The photophysical properties of luminol in a silver nanoparticles complex have been studied by steady-state and time resolved fluorescence spectroscopy. The effect of the serum albumin on the luminol fluorescence in the silver nanoparticles has been also investigated. It was found that the fluorescence quantum yield value of luminol in a silver nanoparticles complex is ??=?0.00407. The decrease of the average fluorescence lifetime value of the luminol in the silver nanoparticles complex was found to be low, <τ>?=?1.712 ns. The luminol does not bind to the serum albumins in the presence of silver nanoparticles. The formation of a new species of luminol on silver nanoparticles is discussed. The results have influence regarding the use of luminol as an assay for bio-analytical applications.     

Synthesis of thiolate-protected silver nanocrystal superlattices from an organometallic precursor and formation of molecular di-<Emphasis Type="Italic">n</Emphasis>-alkyldisulfide lamellar phases

Abstract  

Silver nanocrystal superlattices (NCSs) stabilized by hexadecanethiol have been prepared through reduction of [Ag(hexadecanethiolate)] _n , formed in situ by reaction of the organometallic precursor [Ag(C₆F₅)] and hexadecanethiol. The nanostructures have been characterized by transmission electron microscopy (TEM) and X-ray diffractometry (XRD). Several reaction parameters such as solvent (anisole or toluene), reaction temperature (150 or 120 °C) or silver:thiol ratio (1:1 or 2:1) have been studied. The NCSs are formed by silver nanoparticles which sizes range from 3.7 to 5.1 nm, depending on the reaction conditions. The formation a of lamellar phase of di-n-hexadecyldisulfide by oxidation of the hexadecanethiolate ligands bonded to Ag(I) is detected by XRD.