烯丙基硫脲与支持电解质阴离子在银电极上共吸附的拉曼光谱

用表面增强拉曼散射光谱（ＳＥＲＳ）和时间分辨ＳＥＲＳ光谱（ＴＲＳＥＲＳ）等技术首次研究了烯丙基硫脲（ＡＴＵ）在ＨＣｌＯ４、Ｈ２ＳＯ４和ＨＮＯ３介质中与无机阴离子在银电极上的电化学共吸附行为．提出ＡＴＵ很可能以Ｓ端与银电极表面形成化学吸附键，仲氨基相对伯氨基距离表面较近，整个分子偏向烯丙基一侧倾斜吸附在表面上．ＣｌＯ－４、ＳＯ２－４和ＮＯ－３等弱吸附无机阴离子均能被ＡＴＵ诱导共吸附在其质子化了的仲氨基上，这３种无机阴离子被ＡＴＵ诱导共吸附的强弱顺序是ＣｌＯ－４＞ＳＯ２－４＞ＮＯ－３．被诱导共吸附的无机阴离子对ＡＴＵ在电极表面的化学吸附起到稳定剂的作用，有利于ＡＴＵ在电极表面形成致密的吸附层     

表面增强拉曼光谱研究吸附态的变化

测量了吡啶分子在电化学处理的银表面和亚甲基蓝分子在硝酸刻蚀银表面的表面增强拉曼光谱（ＳＥＲＳ）．对ＳＥＲＳ谱线的分析结果表明，吡啶分子在较低的表面吸附分子密度时倾向于平躺方式；而在较高的表面分子密度时，则倾向于向垂直吸附态转化．亚甲基蓝分子在较低浓度时主要是平躺吸附，随Ｃｌ－浓度的增加，亚甲基蓝从“平躺”吸附态转向“站立”吸附态．     

Ag2CO3溶胶中PABA表面增强拉曼光谱及增强机制的探讨

首次观测到Ａｇ２ＣＯ３溶胶体系中的吸附分子（对氨基苯甲酸ＰＡＢＡ）表面增强拉曼散射（ＳＥＲＳ）效应特强，该体系对ＰＡＢＡ的增强程度比Ａｇ胶还强。同时，分别向该体系加入少量的Ｓ２Ｏ３，Ｆｅ（ＣＮ）６，Ｈ２Ｏ２和ＮＯ３－溶液后，观测其对ＰＡＢＡ的ＳＥＲＳ谱带强度的影响，探讨该体系的增强机制。结果表明，胶体表面的Ａｇ＋或Ａｇδ＋是该体系的ＳＥＲＳ活位吸附点，而表面络合物对其ＳＥＲＳ起到一定的作用。     

拓宽银电极上SERS活性的研究电位范围

电极表面的粗糙化处理是进行表面增强拉曼光谱（ＳＥＲＳ）研究的重要前提，通过研究两种截然不同的氧化还原循环（ＯＲＣ）粗粗糙电极的方法，分析其ＳＥＲＳ活性稳定电位区间与ＯＲＣ还原电位之间的关系，发现高活性的ＳＥＲＳ位皆处于亚稳状态，易随电极电位趋近零电位（ＰＺＣ）而发生表面原子重排，以至推动活性，引入强吸附物种，可以使特殊ＯＲＣ得到的ＳＥＲＳ活性在ＰＺＣ以正电位区稳定存在，并可在ＰＺＣ以负一得到常规Ｏ     

二苯并（b,f）（1,4）氧杂吖庚因在银胶体系中产生SERS的机理探讨

通过滴加ＮａＮＯ３、ＮａＯＨ、ＨＮＯ３、Ｈ２ＳＯ４和ＨＣｌ对银胶体系及ＣＲ（二苯并［ｂ，ｆ］［１，４］氧杂吖庚因）ＳＥＲＳ（表面增强喇曼散射）信号的影响，探讨滴加酸溶液引起银胶体系中ＣＲ瞬即产生ＳＥＲＳ的机理。     

水中Ag电极上取向与结构的SERS研究—不同电极电位和NaClO…

将特殊的ＯＲＣ方法、薄层溶液技术和差谱方法相结合，在较宽的电位区间（－０．７～－２．０Ｖ），将得了不含任何（类）卤素离子的ＮａＣｌＯ４／Ａｇ体系中水的ＳＥＲＳ谱，结果表明，不同浓度的ＮａＣｌＯ４体系中，尽管体相水的结构有很大差别，但电极表面的吸附水有相似的结构特征，即由于电场作用而使有序性较高，并且随电极电位电极负向零电荷电位变化时可能都经历着由单氢端吸附转变为双氢端吸附，继而又转向氧端吸附的取向     

RE（NO3）3与丝氨酸间配合行为的半微量相平衡研究

测定了ＲＥ（ＮＯ３）３－Ｓｅｒ－Ｈ２Ｏ（ＲＥ＝Ｓｍ，Ｇｄ，Ｙｂ）三元体系在２５℃的溶度和饱和溶液折光率，各体系的溶度曲线和饱和溶液折光曲线均由四支组成，分别与ＲＥ（ＮＯ３）３．ｎＨ２Ｏ（ＲＥ＝Ｓｍ，Ｇｄ，ｎ＝６；ＲＥ＝Ｙｂ，ｎ＝５）配合物ＲＥ（Ｓｅｒｉｍｅ）（ＮＯ３）３．４Ｈ２Ｏ（一致溶解化合物），ＲＥ（Ｓｅｒｉｎｅ）４（ＮＯ３）３．６Ｈ２Ｏ（不一致溶解化合物）和Ｓｅｒｉｎｅ相对应。     

THE SYNTHESIS AND CRYSTAL STRUCTURE COMPLEX OF SCHIFF BASE CONTAINING S·N－Cd_3｜CH_3O（O）C_6H_3CH＝NNHC（S）NH_2｜4·（CH_3COO_2·1／2［CH_3S（O）CH_3］·2H_2O

ＴＨＥＳＹＮＴＨＥＳＩＳＡＮＤＣＲＹＳＴＡＬＳＴＲＵＣＴＵＲＥＣＯＭＰＬＥＸＯＦＳＣＨＩＦＦＢＡＳＥＣＯＮＴＡＩＮＩＮＧＳ·Ｎ－Ｃｄ_３｜ＣＨ_３Ｏ（Ｏ）Ｃ_６Ｈ_３ＣＨ＝ＮＮＨＣ（Ｓ）ＮＨ_２｜４·（ＣＨ_３ＣＯＯ_２·１／２［ＣＨ_３Ｓ（Ｏ）ＣＨ_３］·?..     

SYNTHESIS AND￣（183）W NMR CHARACTERIZATI0N OF α－［P＿2W＿（15）O＿（62）Ti＿3］￣（12－） HFTEROPOLYANION

ＳＹＮＴＨＥＳＩＳ　ＡＮＤ￣（１８３）Ｗ　ＮＭＲ　ＣＨＡＲＡＣＴＥＲＩＺＡＴＩ０Ｎ　ＯＦ　α－［Ｐ＿２Ｗ＿（１５）Ｏ＿（６２）Ｔｉ＿３］￣（１２－）　ＨＦＴＥＲＯＰＯＬＹＡＮＩＯＮＳＹＮＴＨＥＳＩＳＡＮＤ￣（１８３）ＷＮＭＲＣＨＡＲＡＣＴＥＲＩＺＡＴ...     

MOLECULAR AND CRYSTAL STRUCTURE OF Co_3（μ－PSCH_2CH_2O）_3（CO）_6 CONTAINING NEW BRIDGING HETEROCYCLIC PHOSPHIDO LIGANDS

ＭＯＬＥＣＵＬＡＲＡＮＤＣＲＹＳＴＡＬＳＴＲＵＣＴＵＲＥＯＦＣｏ_３（μ－ＰＳＣＨ_２ＣＨ_２Ｏ）_３（ＣＯ）_６ＣＯＮＴＡＩＮＩＮＧＮＥＷＢＲＩＤＧＩＮＧＨＥＴＥＲＯＣＹＣＬＩＣＰＨＯＳＰＨＩＤＯＬＩＧＡＮＤＳ￥ＱｉＷａｎｇＬＩＵ；ＸｉａｎｇＨＵ；Ｓｈ?..     

寡聚脱氧核苷酸吸附状态随电位的变化

利用原位电化学及表面增强拉曼散射（SERS）光谱方法对寡聚脱氧核苷酸（26-mers ODN和13-mers ODN）在银电极表面上的吸附状态进行了研究. 实验表明, 单链寡聚脱氧核苷酸在银电极上有很好的SERS光谱,单链寡聚脱氧核苷酸在银表面上主要以碱基腺嘌呤（A）为吸附点,吸附状态随电位变化而变化, 链长较短的寡聚脱氧核苷酸在银电极表面的吸附态对电位变化较敏感.     

Surface-enhanced Raman scattering at the silver electrode/ionic liquid (BMIPF6) interface

This is the first report of in situ SER spectra of chemical species adsorbed on a Ag/room temperature ionic liquid (RTIL) interface. We have investigated the dependence of the SERS intensity of the RTIL derived from 1-n-butyl-3-methylimidazolium hexafluorophosfate (BMIPF6) adsorbed on a silver electrode. It has been shown that the BMI+ adsorbs on the silver electrode for potentials more negative than -0.4 V vs a Pt quasireference electrode (PQRE). In the -0.4 to -1.0 V potential range the SER spectra are similar to the Raman spectrum of the RTIL BMIPF6. At potentials more negative than -1.0 V some imidazolium ring vibrational modes and N-CH3 vibrations are enhanced, suggesting that the imidazolium ring is parallel to the surface and for potentials <-2.8 V the BMI+ is reduced to the BMI carbene. The potential dependence of the SERS intensities of Py adsorbed on a silver electrode in BMIPF6 has also been investigated. The results have shown that at potentials less negative than -0.8 V (vs PQRE) Py adsorbs at an end-on configuration forming an Ag-N bond. In the -0.9 to -1.4 V potential range Py molecules lie flat on the electrode surface and at potentials <-1.4 V Py is replaced by the BMI+. The electrochemical and SERS results have shown that Py has the effect of changing the oxidation of silver in that medium as well as the reduction of BMI+ to the BMI carbene. In the presence of Py the BMI+ reduction is observed at potentials near -2.4 V. The Ag electrode has presented SERS activity from 0.0 to -3.0 V.     

银电极表面异亮氨酸单分子膜结构和表面性质的表面增强拉曼光谱研究

利用表面增强拉曼光谱(SERS)技术研究了在粗糙化银电极表面吸附的异亮氨酸自组装单层膜结构及其表面性质随溶液酸碱性和电极电位改变的特征.研究结果表明溶液pH值的变化并没有显著改变异亮氨酸分子在银电极表面以去质子化羧基吸附为主的特征.借助于高氯酸根离子这一SERS光谱探针,对异亮氨酸单分子膜的表面酸碱性质进行了表征和分析.而就电位改变对该单分子膜结构的影响而言,在所研究的电位范围内,单分子膜中的异亮氨酸分子是通过去质子化羧基与氨基两个位点而吸附的,且吸附作用随电位负移而呈现有规律的变化.     

电极表面Ag(δ+)-NH3络合物的表面增强拉曼散射效应

本文采用氧化还原循环处理电极首次得到Ag/0.1 mol L~(-1)NH_3+0.1 mol L~(-1)NH_4Cl体系中吸附在银电极上氨分子的表面增强拉曼散射(SERS)效应。按氨分子在电极表面上的吸附量为每平方厘米8×10~(15)计算, 增加因子为1.2×10~5。谱峰强度及位置随电极电位改变。吸附氨分子的SERS谱与Ag(NH_3)_2~+的正常拉曼光谱类似。本文结果表明电极表面上存在Ag(δ+)络合物, 它可能是SERS效应的活性中心, 用这个概念可较好地解释本文实验结果。通过谱图分析给出了Ag(δ+)表面络合物的可能结构模式。     

Orientation of 6-mercaptopurine SAMs at the silver electrode as studied by Raman mapping and in situ SERS

Self-assembled monolayers (SAMs) of 6-mercaptopurine (6MP) on a silver electrode in acid and alkaline media were investigated by a combination protocol of the SERS technique with Raman mapping, and it was found that the adsorption mode of 6MP SAMs changed with the pH value of the environment. Quantum calculations for the vibrational mode were performed by the BLYP/6-31G method. 6MP was adsorbed on the silver electrode with a tilted orientation via S, N1, and N7 atoms in acid medium, while the SAMs adopted head-on adsorption modes with the S atom and the N1 atom anchoring the silver surface in alkaline medium. However, 6MP SAMs turned to the same upright orientation on the electrode through the S and N7 atoms when either acid or basic solution was removed. Stability of 6MP SAMs was observed by in situ SERS spectroelectrochemical measurements. The results reveal that the desorption potentials of 6MP SAMs formed under acid and alkaline conditions from the Ag electrode were at ca. -1.3 V and -1.6 V vs SCE, respectively.     

Surface-enhanced Raman scattering study of riboflavin on borohydride-reduced silver colloids: Dependence of concentration, halide anions and pH values

The influences of concentration, halide anions and pH on the surface-enhanced Raman scattering (SERS) of riboflavin adsorbed on borohydride-reduced silver colloids were studied. The optimum concentration for the SERS of riboflavin is 10(-6)mol/L while the SERS enhancement varies for different modes. The addition of 0.2mol/L halide (NaCl, NaBr, and NaI) aqueous solutions, leads to a general decrease of the SERS intensity and a change of spectral profile of riboflavin excited at 514.5nm. Riboflavin interacts with the silver surface possibly through the CO and N-H modes of the uracil ring. The SERS spectra of riboflavin were recorded in the 3.4-11.6 pH range. By analyzing several SERS marker bands, the protonated, deprotonated or the coexistence of both molecular species adsorbed on the colloidal silver particles was proved.     

Rapid detection of Rosa laevigata polysaccharide content by near-infrared spectroscopy

We have investigated surface-enhanced Raman spectroscopy (SERS) spectrum of Omethoate (O,O-dimethyl-S-methylcarbamoylmethylthiophosphate). It is found significant signals in the ordinary Raman spectrum for solid-state Omethoate as well as strong vibrational signals absorbed on the silver sol surface which is prepared by γ-irradiation technique at a very low concentration. Effects of pH and anions (Cl-, Br-, I-) on the adsorption orientation are investigated as well. Two different adsorption mechanisms are deduced, depending on the experimental conditions. The sulfur atom or the sulfur and two oxygen atoms are adsorbed onto the silver sol surface. Among halide ions, Br- and I- are more strongly adsorbed onto the silver sol surface. As a result, the adsorption of Omethoate is less effective due to their steric hindrance.     

A DFT Investigation of Surface‐Enhanced Raman Scattering of Adenine and 2′‐Deoxyadenosine 5′‐Monophosphate on Ag20 Nanoclusters

We present a detailed analysis of the surface‐enhanced Raman scattering (SERS) of adenine and 2′‐deoxyadenosine 5′‐monophosphate (dAMP) adsorbed on an Ag₂₀ cluster by using density functional theory. Calculated Raman spectra show that spectral features of all complexes depend greatly on adsorption sites of adenine and dAMP. The complexes consisting of adenine adsorbed on the Ag₂₀ cluster through N3 reproduce the measured SERS spectra in silver colloids, and thus demonstrated that adenine interacts with the silver surface via N3. We also investigate the SERS spectrum of adenine at the junction between two Ag₂₀ clusters and demonstrate that adenine can bind to the clusters through N3 and the external amino group, while dAMP can be adsorbed on the cluster in an end‐on orientation with the ribose and phosphate groups near to or away from the silver cluster. In contrast to the adenine–Ag₂₀ complexes, the dAMP–Ag₂₀ complexes produce new and strong bands in the low‐ or high‐wavenumber region of the Raman spectra, due to vibrations of the ribose and phosphate groups. Furthermore, the spectrum of dAMP bound to the Ag₂₀ cluster via N7 approaches the experimental SERS spectra on silver colloids.     

An investigation of the surface enhanced Raman scattering (SERS) from a new substrate of silver-modified silver electrode by magnetron sputtering

'Pure' silver nanoparticles on silver electrode were prepared by magnetron sputtering. The silver-modified silver electrode has good stability and the silver nanoparticles on silver electrode have homogeneous size distribution. Compared with the silver colloid modified silver electrode, there were no any extraneous component ions on the electrode, for the modified silver nanoparticles are prepared by magnetron sputtering. Synchronously, we obtained much higher quality SERS spectra of adenine molecules on the silver electrode modified by magnetron sputtering (SEMMS), and the study of the adsorption behavior of adenine on the silver-modified silver electrode by surface enhanced Raman scattering (SERS) indicated that the silver-modified silver electrode was highly efficient substrates for SERS investigation. From the rich information on the SEMMS obtained from high-quality potential-dependent SERS, we may deduce the adsorption behavior of adenine and the probable SERS mechanism in the process. The probable reasons are given.     

Surface-enhanced Raman scattering of a series of n-hydroxybenzoic acids (n = P, M and O) on the silver nano-particles

Surface-enhanced Raman scattering (SERS) spectra of a series of n-hydroxybenzoic acids (n-HBA, n = P, M and O) adsorbed on the silver nano-particles were studied, respectively, in the silver colloidal solution and on the dried silver-coated filter paper. On the same substrate, the different molecules' SERS spectra were different, while on the different substrates the same molecules' SERS spectra were also different. Significant changes were found in the SERS spectra of PHBA molecules adsorbed on the two substrates, and the changes found in MHBA's spectra on two substrates were next to PHBA's, while almost no changes were found in the spectra of OHBA molecules. Moreover, it was found, on the filter paper, that the SERS spectra of the same molecules would change with the coverage density of the silver nano-particles. The analyses showed that the origins of these changes were the different adsorption behavior of molecules adsorbed on the silver nano-particles. Because in these three molecules the relative positions of the carboxyls and hydroxyls on the benzenes are different, the adsorption behaviors of these three molecules adsorbed on the silver surfaces are also different. The experimental results suggest that the surface characteristic of the substrate and the surface configuration of the adsorbate could exert a great influence on the adsorption behavior of the adsorbates on the substrates.