均二苯乙烯类双光子荧光探针的合成及对金属离子的识别

合成了以均二苯乙烯为荧光母体, 一端以N,N-二甲基, 一端以7-苯基-1-氧杂-4,10-二硫杂-7-氮杂环十二烷(NS2O)为受体的荧光探针(DMNS2O), 并用1H NMR等技术对其进行了结构鉴定. 通过X射线单晶衍射分析发现均二苯乙烯的3个苯环非共平面, 二面角分别为24.6°和37.5°; 在加入金属离子Ag+和Zn2+之后, 探针在600 nm处的荧光峰消失, 420 nm处产生新的荧光峰, 其它金属离子的干扰较小.双光子荧光激发研究结果表明, 当激发波长为750 nm时, 双光子荧光发射最强.     

罗丹明类荧光探针的合成及对铜离子的检测

合成了罗丹明类Cu2+荧光增强型分子探针3',6'-双(二乙氨基)-2-(N-乙叉基氨基)螺[异吲哚-1,9'-占吨]-3-酮（RA）,并研究了它的光谱性能及对铜离子的识别作用.在乙腈/水（体积比1/1）的介质中,当加入Cu2+后探针RA显玫瑰红色,最大吸收波长为548 nm,最大发射波长为571 nm,且荧光强度显著增强,但是,其它常见离子如Na+, K+, Mg2+, Ca2+, Mn2+, Cd2+, Cr3+, Co2+, Ni2+, Ag+, Pb2+, Zn2+, Fe3+, Hg2+不引起或引起很小的紫外/可见或荧光光谱变化.RA的选择性荧光增强主要是由于Cu2+诱导分子中的酰胺闭环结构发生开环,导致分子结构的共轭程度增大.在6.5×10-8～2.9×10-6 mol?L-1范围内RA可以有效检测Cu2+,检测限为5.0×10-8 mol?L-1.RA对Cu2+的识别不可逆,而且探针RA对pH值不敏感,可以在比较宽的范围内（pH=4.1～10.5）高灵敏、高选择性检测Cu2+.     

一种1,8-萘酰亚胺Cr~(3+)离子荧光探针的研究

以4-硝基-1,8-萘酐、N,N-二甲基乙二胺为主要原料合成了一种荧光探针:4-(2′-N,N-二甲基氨基乙基)氨基-N-(2-N,N-二甲基氨基)乙基-1,8-萘酰亚胺(DDN)。研究了其紫外可见吸收和荧光发射光谱。考察了Fe3+,Cr3+,Mn2+,Ni2+,Zn2+,Cu2+和Co2+离子对该化合物荧光发射光谱的影响,结果表明Cr3+离子能使DDN荧光显著增强。滴定实验结果推测DDN与Cr3+的结合比为1∶2。在DDN浓度为1.0×10-5mol/L时,Cr3+浓度在5.0×10-7~2.0×10-5mol/L范围内,DDN荧光强度(F)与Cr3+离子浓度[Cr3+]呈良好的线性关系,线性方程为F=9430.3527+14600.2973[Cr3+],相关系数r=0.9976。检测限为4.3×10-7mol/L。     

基于羟苯基苯并咪唑的Zn2+比率荧光探针

通过羰基将两分子2-(4-氨基-2-羟苯基)苯并咪唑(4-AHBI)连接,合成了结构高度对称的新化合物N,N′-二-[3-羟基-4-(2-苯并咪唑)苯基]脲(C27H20N6O3,1),测试了不同溶剂条件下1的紫外吸收和荧光发射光谱,研究了1对Zn2+的选择性识别作用。结果表明,随着溶剂极性的增大,1的紫外吸收峰发生蓝移,激发态分子内质子转移(ESIPT)荧光发射峰明显增强。与4-AHBI相比,1在乙腈溶液中的紫外吸收强度增强约3.5倍,最大吸收峰红移8 nm,荧光发射增强8倍多。1在乙腈溶液中的Zn2+荧光响应行为表明1与Zn2+的结合将导致1在445 nm处的荧光强度不断降低,而在395 nm处出现的新峰的荧光强度不断增强,具有比率荧光探针的特点,而且检测范围较宽,可达1×10-6-1×10-2 mol.L-1。     

汞离子的高灵敏度裸眼识别和荧光传感探针

设计合成了一种以耐尔蓝为母体的Hg2+光学探针分子1-苯甲酰-3-{2-[9-(乙氨基)-10-甲基-9H-苯并[α]苯酚-5-胺基]乙基}硫脲盐酸盐(NBET). 在pH=7.4的Tris-HCl缓冲液中, 探针分子最大吸收波长为640 nm, 此时溶液为淡蓝色; 加入汞离子可以诱导探针分子在640 nm处的吸收降低, 并在556 nm处产生新的吸收峰, 溶液变为浅紫色, 而其它金属离子的加入未引起显著变化, 基于此可对水溶液中的痕量Hg2+进行裸眼识别. 荧光光谱显示, 汞离子可以特异性地猝灭探针分子在660 nm处的荧光发射. 该探针分子的灵敏度、选择性及荧光量子产率高, 激发/发射波长长, 可以实现水溶液中0.005 μmol/L Hg2+的荧光检测.     

邻羟基萘甲醛缩对二甲氨基苯甲酰腙的合成及其对锌离子的识别

设计并合成了用于识别锌离子的荧光传感分子——2-羟基-1-萘甲醛缩-4-二甲氨基苯甲酰腙(1),其结构经1H NMR,IR和MS表征。利用荧光光谱研究了在乙腈中1对过渡金属离子(Zn2+,Cd2+,Cu2+,Hg2+,Pb2+和N i2+)的识别能力。结果表明:1表现出对Zn2+的良好选择性,Zn2+的加入导致1的长波长荧光增强449倍。Job曲线确定1与Zn2+形成1∶1型配合物。     

基于香豆素骨架的重金属和过渡金属离子荧光探针的研究进展

按照对不同金属离子的识别归类总结了近五年来以香豆素为荧光基团的重金属和过渡金属离子(Cr3+,Cd2+,Pb2+和Hg2+;Fe3+,Co2+,Ni2+,Cu2+,Zn2+和Ag+)荧光探针的研究进展,并简要介绍了该类探针的设计、作用机理及应用,展望了该领域的发展趋势。     

5-N,N-二乙氨基-2-(吡啶-2’-亚氨甲基)苯酚的合成及其对Zn~(2+)的识别

本文利用2-氨基吡啶与4-N,N-二乙氨基水杨醛反应合成了5-N,N-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚(探针L),并对其结构进行了表征。在DMSO/Tris(体积比6∶4,p H=7. 4)溶液中,探针L高选择性荧光"关-开"识别Zn2+,在365nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L与Zn2+的结合比为1∶1,结合常数为2. 6×103L/mol,检测限为9. 39×10-7mol/L,p H适用范围为7～11,并可检测水样中的Zn2+。     

一种基于DPA识别基团的可视化检测锌离子的荧光增强型探针

以N,N-二(2-吡啶甲基)胺(DPA)为识别基团,设计合成了一种用于检测Zn2+的荧光增强型探针WN,在CH3CH2OH/TrisHCl(1∶9,V/V,pH=7.4)缓冲溶液中研究了它对Zn2+的识别特性。实验结果表明,WN对Zn2+有较高的选择性和灵敏度,它们之间的结合比为1∶1,对Zn2+的检出限为1.14×10-8 mol·L-1。WN能够快速地可视化检测Zn2+,在HeLa活细胞中对Zn2+的荧光显微成像表明WN可应用于生物体的检测。     

基于脱氧核酶的新型铅离子荧光探针

将荧光猝灭基团修饰的17E脱氧核酶(17E DNAzyme)与荧光基团修饰的底物链通过6个脱氧核苷酸相连, 得到了一种新型的对Pb2+敏感的荧光探针. 由于DNAzyme与底物链发生分子内杂交, 荧光基团与猝灭基团相互靠近, 导致荧光猝灭. 当Pb2+存在时, DNAzyme被激活, 底物链被切断后释放出荧光基团标记的DNA片段, 从而产生明显的荧光信号. 据此可在常温下快速检测Pb2+, 检测下限为10 nmol/L. 在Zn2+, Mn2+, Co2+, Cd2+, Cu2+, Mg2+和Ni2+等多种二价金属离子中, 除Zn2+, Mn2+和Cd2+略有干扰外, 其它几种金属离子均无响应, 表明该荧光探针对Pb2+具有良好的选择性.     

新型不对称卟啉配体及其锌配合物的合成与荧光性能

以3,5-二羟基苯甲酸丙酯和5-(4-硝基)苯基-10,15,20-三苯基卟啉为起始原料,合成了新型的不对称卟啉配体——5-[4-(3,5-二-十六烷氧基苯甲酰亚胺基)苯基]-10,15,20-三苯基卟啉(1)及其锌配合物(2),其结构经UV-Vis,1H NMR,IR和元素分析表征。用荧光激发光谱研究了1和2的荧光性能,结果表明:在激发波长为420 nm时,1和2的荧光发射峰分别在650 nm,709 nm和600 nm,644 nm。     

Spectrofluorimetric determination of iron(III) with 2-pyridinecarbaldhyde-5-nitro-pyridylhydrazone in the presence of hexadecyltrimethylammonium bromide surfactant

2-pyridinecarbaldehyde-5-nitro-pyridylhydrazone (2PC-5NPH) was synthesized and its application in the spectrofluorimetric determination of Fe(III) ions in the presence of surfactants was examined. An emission peak of 2PC-5NPH, which increased remarkably by the addition of Fe(III), occurs at 420 nm upon excitation at 300 nm, and allows for the sensitive, selective determination of the ferric ion in the 0.20-1.45 mug ml(-1) range. The detection limit is 0.028 mug ml(-1) in the presence of hexadecyltrimethylammonium bromide (CTMAB).     

ENERGY TRANSFER FROM CHLOROPHYLL b TO CHLOROPHYLL a IN A HYDROPHOBIC MODEL SYSTEM

Abstract— Chlorophyll a and chlorophyll b purified by high-performance liquid chromatography (HPLC) were subsequently adsorbed on the surface of a pellicular reverse phase packing normally used in HPLC. The granule surface is reacted with octadecyl groups and furnishes an hydrophobic substrate for pigment adsorption. Reflectance spectra of chlorophyll a and chlorophyll b , each adsorbed at average spacings of about 11 nm² per molecule, had red region maxima at 664 and 643nm respectively. Fluorescence excitation spectra for 740nm emission from these surfaces peaked at about 420nm for chlorophyll a and 460nm for chlorophyll b. Adsorbed pigments excited at either of the two wave lengths had a single fluorescence emission peak at 683nm for chlorophyll a and at 664nm for chlorophyll b. A surface having both pigments adsorbed in approximately equal amounts with an overall average spacing of about 5.6nm² per molecule also had peaks at 420 and 460nm in the excitation spectrum. However, excitation of adsorbed molecules on this (latter) surface, at either 420 or 460nm, produced emission with the single chlorophyll a peak at 683nm. It is concluded that, under the conditions of our experiment, exciting adsorbed chlorophyll b contributes strongly to emission from adsorbed chlorophyll a.     

Extracellular biosynthesis of silver nanoparticles using the fungus Aspergillus fumigatus

Development of reliable and eco-friendly process for synthesis of metallic nanoparticles is an important step in the filed of application of nanotechnology. One of the options to achieve this objective is to use natural processes such as use of biological systems. In this work we have investigated extracellular biosynthesis of silver nanoparticles using Aspergillus fumigatus. The synthesis process was quite fast and silver nanoparticles were formed within minutes of silver ion coming in contact with the cell filtrate. UV–visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) micrograph showed formation of well-dispersed silver nanoparticles in the range of 5–25 nm. X-ray diffraction (XRD)-spectrum of the silver nanoparticles exhibited 2θ values corresponding to the silver nanocrystal. The process of reduction being extracellular and fast may lead to the development of an easy bioprocess for synthesis of silver nanoparticles.     

Spectroscopic observations on photofading and fluorescence changes of eosin Y solutions in the presence of sodium azide

Eosin Y solutions exposed to illumination with visible light showed a decreased absorption at 513 nm with increasing irradiation time. In the presence of the singlet oxygen quencher sodium azide, photofading at 513 nm was somewhat lower and a new and small absorption band at 420 nm was observed. Eosin Y fluorescence at 538 nm also decreased with illumination, while a new emission peak appeared at 478 nm. The presence of sodium azide largely increased the photoinduced emission at 478 nm.     

Selective excitation of singly-ionized silver emission lines by Grimm glow discharge plasmas using several different plasma gases

The relative intensities of silver emission lines from Grimm glow discharge plasmas were investigated in the wavelength range from 160 to 600 nm when using different plasma gases. It was characteristic of the plasma excitation that the spectral patterns were strongly dependent on the nature of the plasma gas employed. Intense emission lines of silver ion were observed when argonhelium mixed gases were employed as the plasma gas. Selective excitation of the ionic lines could be principally attributed to the charge transfer collisions between silver atoms and helium ions.     

Thiourea-based molecular clips for fluorescent discrimination of isomeric dicarboxylates

A new clip-like receptor, which comprises two thiourea-based binding groups and two naphthalene units, has been designed and synthesized as a fluorescent chemosensor for distinguishing o-phthalate from two other isomers of dicarboxylates. Upon the addition of these three ions, the emission intensity at 420 nm (excitation at 340 nm) decreases drastically through PET. When excited at 380 nm, a new emission band at 460 nm appears and develops gradually upon the addition of the o-phthalate ion and the fluorescent intensity increases markedly over time, but the presence of m-phthalate or p-phthalate do not cause this kind of change. It suggests a guest-induced "off-on" conformational switching signaling transduction. The presence of the o-phthalate anion induces a special conformation with two naphthalene units positioned close enough to exhibit a new emission.     

TiO2浓度对核-壳结构Ag/TiO2纳米复合粒子结构以及三阶非线性光学性质的影响

采用光还原方法制备了核-壳结构的Ag/TiO2纳米复合粒子, 通过TEM、UV-Vis光谱和XRD表征了不同TiO2浓度下Ag/TiO2纳米复合粒子的结构和光学性质. UV-Vis光谱证明了银颗粒的存在, 且复合粒子中的银粒径随着TiO2含量的增加而增加, 同时随着TiO2浓度的增加, 银的吸收峰出现明显的增强和展宽；从TEM照片 发现, Ag/TiO2纳米复合粒子是一种以Ag为核, 外面包覆一层TiO2的核-壳结构, TiO2浓度和Ag+浓度的增加, 使得复合粒子的银颗粒粒径增大. 用Z-扫描技术, 以锁模Ti:sapphire飞秒激光器发出的脉宽为130 fs激光做光源, 在790 nm波长的光作用下, 研究了0.5%(w)Ag+含量, 不同TiO2浓度的Ag/TiO2纳米复合粒子的非线性光学特性. 结果发现, 在790 nm激光作用下, 0.25%(w)TiO2样品膜有双光子吸收和自聚焦非线性折射现象; 而当TiO2浓度为0.70%(w)时, 样品膜的非线性吸收由反饱和吸收转变为饱和吸收.     

硫化镉准纳米圆球的人工活性膜法控制合成及其性能研究

首次利用胶棉人工活性膜板，在0.1mol/L CdCl_2溶液和0.1mol/L Na_2S溶液 组成的隔膜组装体系中，成功制备了硫化镉准纳米圆球。产物粒径范围80～280nm ，平均粒径～170nm，圆球边界清晰，为立方闪锌矿多晶结构，晶格常数a=0. 5818nm。光学性质研究表明，当激发波长为390nm时，出现了波长为480nm的蓝光和 535nm的绿光两个发射峰；紫外-可见光谱在475nm处有最大吸收，与常规材料相比 “蓝移”了40nm，表现出明显的量子尺寸效应。另外还对产物合成机理进行了探讨 。