新型BODIPY荧光染料的合成及光谱性质研究

传统的BODIPY荧光染料具有荧光量子效率高、摩尔消光系数大、紫外吸收和荧光发射峰窄等优点,然而这类荧光染料普遍存在荧光发射波长短和Stokes位移小的缺点,因而限制了它们在体内生物传感及成像方面的广泛应用。为了得到荧光发射波长较长和Stokes位移大的BODIPY荧光染料,以BODIPY母核为基本结构,通过在它的8位连接吸电子性质的酯基来增加分子内电荷转移程度,同时在其3,5位引入供电子的芳香取代基增加分子的π共轭结构,合成得到了一类8位酯基取代的新型BODIPY荧光染料。所得到的新型BODIPY荧光染料的化学结构经过1H NMR, 13C NMR和HR-MS得以确认。光谱测试结果表明,这类染料的紫外吸收光谱(λ_abs=536 nm)和荧光发射光谱(λ_em=592 nm)与普通的BODIPY相比都发生显著红移(80 nm),并且保持了较高的荧光量子效率(Ф=0.43)。此外,这类BODIPY荧光染料的紫外可见吸收光谱和荧光发射光谱几乎完全分开,Stokes位移长达60 nm,可以有效地避免自吸收和生物样品的背景干扰。密度泛函理论计算结果表明,这种相对较大的Stokes位移主要是由于染料分子在基态和激发态下不同的几何构型所造成的。该类化合物的光物理性能受溶剂的影响小,是一类性能优良的新型荧光染料。细胞成像结果表明,染料1具有良好的细胞渗透性和光稳定性,可以实现对细胞的荧光成像。     

溶剂对石墨烯量子点荧光性质的影响

采用柠檬酸热解法制备了石墨烯量子点(GQDs),研究了非极性溶剂戊烷,极性溶剂乙醇、丙酮、乙二醇对GQDs荧光性质的影响。透射电子显微镜(TEM)和原子力显微镜(AFM)图像表明,制备的GQDs尺寸分布在2~12 nm(平均尺寸为4.9 nm),分散均匀,高度分布在0.5~2 nm。吸收光谱表明,GQDs具有明显的紫外吸收特性,吸收峰位于259 nm和274 nm。光致发光谱表明,GQDs的发光具有明显的溶剂依赖性。GQDs在极性溶剂乙醇、丙酮、乙二醇中,发光峰的位置依赖于激发波长,发射波长在可见光区。而在非极性溶剂戊烷中,GQDs表现出对激发波长不依赖的荧光性能,且发射波长在近紫外。     

溶剂对TNS与ANS荧光光谱的影响

研究了两种光谱探针TNS与ANS在不同溶剂中的荧光光谱,为此类荧光探针的应用奠定了一定的基础。结果表明溶剂对TNS与ANS荧光光谱的影响是一般溶剂效应与特殊溶剂效应共同作用的结果。     

Effect of Matrix Treatment on Spectroscopic Properties of HCl Catalysed Sol-Gel Glasses Containing Coumarin Laser Dyes

Coumarin 1, Coumarin 2 and Coumarin 120 are embedded in transparent sol-gel glass samples prepared by sol-gel process using dip method. The sol-gel matrix is given dip treatment with Methanol /Distilled Water (50/50vol) for 1 to 16h before dipping into dye solution. The effect of dipping time of matrix in Methanol/ Distilled Water on spectroscopic properties of coumarin dye doped glass samples has been studied. The Optical Density (OD) at absorption maximum wavelength and Fluorescence Intensity (FI) at fluorescence maximum wavelength of all coumarin dyes increase with the time of dipping of the sol-gel sample. These absorption/fluorescence properties of coumarin dyes in sol-gel glass matrices are compared with its respective properties in methanolic solution in acidic environment. The cause of these changes in OD/FI with dipping time is discussed by taking into account the absorption / fluorescence of dye in acidified methanol.     

Photophysical Characterization of New 3-Amino and 3-Acetamido BODIPY Dyes with Solvent Sensitive Properties

The structural, electronic and photophysical properties of three new asymmetric, highly fluorescent difluoroborondipyrromethene (BODIPY) dyes, bearing an amino or an acetamido group at position 3 of the chromophoric core, have been studied in different apolar, polar and polar/protic solvents. The presence of the 3-amido group extents the delocalization of the π-system, leading to bathochromic shifts in the absorption and fluorescence bands, as predicted by quantum mechanic calculations. The 3-amino dye shows photophysical properties highly dependent on the solvent polarity and acidity, and is characterized by a hypsochromic shift of its absorption band, with regard to the corresponding acetylated dye, as well as a low fluorescence quantum yield in acid media with proton concentration lower than 4 × 10⁻⁴ M. In media with higher proton concentration, the BF₂ bridge group of the 3-amino dye is removed, yielding the corresponding non-fluorescent dipyrromethene precursor. These results suggest that the 3-amino dye could be used as a fluorescence probe for the study of the acidity of different environments.     

Spectroscopic Study of Solvent Polarity on the Optical and Photo-Physical Properties of Novel 9,10-bis(coumarinyl)anthracene

Novel 7,7′-((anthracene-9,10-diylbis(methylene))bis(oxy))bis(4-methyl-2H-chromen-2-one) (BisCA) was prepared as fluorescent probe. The chemical structure of the novel BisCA was confirmed by spectroscopic data as well as elemental analyses. The solvatochromic characteristics of the new proble and its precursors were investigated in different solvents including, ethanol, DMF and toluene as protic polar, aprotic polar and non-polar solvents, respectively. Photo-physical parameters of probes, such as fluorescence quantum yields, fluorescence lifetime of excited state, radiative and non-radiative decay, were assessed in different media. The intermolecular H-bond effect on absorption and excitation spectra of the novel probe was reported in different solvents. Also, Onsager cavity radius and dipole moment of ground state and excited state of the probe were calculated as described by Bakhshiev and Reichardt methods.     

Spectroscopic Studies of Some Organic Compounds: Aprotic Solvent Effects on Electronic Absorption Spectra of Nicotinamide

Abstract

The electronic absorption spectra of nicotinamide were measured in seventeen aprotic solvents. The solvatochromic method is used to unravel solvent polarity and hydrogen bonding effects on π ? π? transition. Solvent effects are rationalized in terms of the solvatochromic parameters: π?, δ, α, and β.     

Spectroscopic Properties and Three-photon Absorption Induced Optical Limiting of Series of Novel Nonlinear Chromophores

合成了三种新的具有D-π-D型分子结构和延伸共轭长度的非线性生色团,溶剂化显色分析显示由于跃迁时在基态和激发态之间有较大的偶极矩变化从而表现出较强的分子内对称电荷转移的性质.探讨了这些非线性生色团的基于三光子吸收的光限幅效应,在波长为、1064 nm的纳秒脉冲的作用下,呈现较大的三光子吸收系数,相应的生色团分子的三光子吸收截面高达10-74 cm6s2数量级.     

New Series of Dyes for Flashlamp-Excited Lasers

A new series of laser compounds which are derivatives of 7H-benzo[4, 5]imidazo[1, 2-c]chromeno[3, 2–e]pyrimidine have been developed and their working characteristics are presented. It is shown that the new compounds fluoresce with a high quantum yield (0.83–0.97) in the green spectral region; their methanol solutions gave effective lasing upon flashlamp excitation with a pulse duration of about 2.0 sec at the level 0.5. In a nonselective cavity they emit laser radiation in the range 540–570 nm. The influence of the molecular structure of the investigated dyes on their fluorescence and laser characteristics is discussed.     

Investigation of Solvent Effects on Photophysical Properties of New Aminophthalimide Derivatives-Based on Methanesulfonate

Novel aminophthalimide derivatives were synthesized starting from (3aR,7aS)-2-(2-hydroxypropyl)-3a,4,7,7a–tetrahydro-1H-isoindole-1,3(2H)-dione (9) , and solvent effects on the photo-physical properties of these newly synthesized aminophthalimide derivatives (compounds 14 and 15) were investigated using UV-Vis absorption spectroscopy, steady-state and time-resolved fluorescence measurements. Both absorption and fluorescence spectra exhibited bathochromic shift with the increased polarity of the solvents for both molecules. Solute-solvent interactions were analyzed using the Lippert-Mataga and Bakhshiev polarity functions, and Kamlet-Taft and Catalan multiple linear regression approaches. The results revealed that these two molecules experienced specific interactions. Furthermore, photo-physical parameters were calculated for both molecules in all of the solvents, such as the fluorescence quantum yield, fluorescence lifetime, radiative (k_r) and non-radiative (k_nr) rate constant values. It was observed that the fluorescence quantum yield values decreased linearly with increasing solvent polarity. This study proved the new dyes including isopropyl methanesulfonate group displayed different behavior from previous studies of aminophthalimide derivatives in water. It was recommended that these new dyes having interesting properties by changing solvent can be used various applications such as environmentally sensitive fluorescent probes, labels in biology, laser industry.     

Spectroscopic Evaluation of Effects of Heat Treatments on the Structures and Emulsifying Properties of Caseins

The effects of heat treatment (heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy. Heat treatment from 60 to 100 ℃ resulted in an increase in their fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying activity index, but decreased the size polydispersity of caseins. In the pH range of 5.5 to 7.0, the fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying properties decreased with increased heating pH, but the size polydispersity of caseins increased with increased pH. The relationship between the surface fluorescence intensity and emulsifying activity was also investigated, revealing a correlation coefficient of 0.90. These results suggested that heat treatment could be used to modify the structures and emulsifying properties of caseins by appropriately selecting heating conditions.     

KE型染料与Gemini阳离子表面活性剂T122的光谱研究

在室温(25℃)下,通过紫外-可见光谱法及稳态荧光法分别测定了Gemini型阳离子表面活性剂T122和传统阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)与三种KE型活性染料相互作用后的临界胶束浓度(CMC),并对二者作用的机理进行了初步分析。实验结果表明,两种方法测出的CMC值基本吻合;KE型染料的加入都能使阳离子表面活性剂的CMC值有所提高;如染料黄KE-4R的加入使表面活性剂T122的CMC增至不加染料前的7.0倍,而CTAB的CMC值增加至原来的1.5倍;带有双亲分子结构的表面活性剂T122的性能要明显优于传统表面活性剂CTAB。     

CuO纳米粒子的谱学特性研究

以六次甲基四胺为沉淀剂宿主、Cu(NO3)2为铜源在乙醇-水(1∶1,φ)体系中采用均匀沉淀法合成了前驱体Cu2(NO3)(OH)3,然后在不同温度下锻烧获得系列纳米CuO粉体,借助XRD,FTIR,XPS,FT-Raman和UV-Vis等测试手段对其谱学特性进行了系统研究。XRD分析表明,所得粉体为单斜晶系的纳米CuO,随锻烧温度的升高,粉体的粒径增大;XPS图谱表明,随热处理温度的升高CuO粉体的表面氧空位减少,导致表面吸附氧含量降低;FTIR图谱表明,随晶粒粒径的减小,在525cm-1附近处Cu—O键特征吸收峰明显宽化,且发生劈裂,劈裂小峰出现双移现象;FT-Raman谱图表明,随着粒径的减小,样品的拉曼散射峰出现宽化现象,并向低波数方向移动;UV-Vis吸收光谱表明,粉体在300～400nm之间有强的吸收,随着粒径的减小最大吸收发生蓝移。探讨了上述谱学规律的成因,对氧化物纳米粒子的谱学特性研究具有重要的借鉴意义。     

Spectroscopic Studies of Some Organic Compounds: Solvent Effects on 1H NMR Shift of Amine Proton of Morpholine

Abstract

The influence of the aprotic Solvents on the ¹H NMR spectra of the N-H proton has been studied. The chemical shift shows quite good correlation with the solvatochromic parameters, π?, β, and α, while a fair correlation with the Gutmann donor and acceptor numbers were obtained.     

Biscoumarins - New Laser Dyes in Coumarin Series

With a view to extend the tunability range using new derivatives in the coumarin series of dyes, a novel series have been synthesized, viz. the biscoumarins where two coumarin nuclei are coupled. These are studied for their lasing characteristics, optical spectra and quantum efficiencies. Laser spectra of these dyes in various solvents are also studied. Tunability range of these dyes have been found to cover blue green region of the spectrum and though there is shift to longer wavelength as compared to monocoumarins, extending the tunability range, it is not as much as would be normally expected with extended conjugation involving two coumarin nucled.     

沢吨染料的光化漂白动力学及全息特性研究

研究了以三乙醇胺作为引发剂,五种沢吨染料的光化漂白过程.实验结果表明五种染料的光化漂白速率大小顺序是藻红B(ErB)＞曙红Y(EY)＞孟加拉玫瑰红B(RsB)＞罗丹明B(RoB)＞荧光素(F).并研究了曝光强度及染料浓度对漂白过程的影响,以及这五种染料的全息记录性能.     

溶剂效应对发光聚合物性能的影响

以共轭聚合物MEH—PPV和DD—PPV为研究对象，利用UV—Vis吸收光谱和荧光光谱，研究了它们在不同溶剂中及固体膜状态下的发光性质，探索了聚合物的微观结构与其发光性能之间的关系。结果表明。由于聚合物在固体膜状态下较溶液状态有紧密的排列，因此其UV—Vis吸收光谱和荧光光谱与溶液相比发生了较大的红移；相同主链的聚合物，侧链取代基的电负性减弱，可使UV—Vis吸收光谱和荧光光谱发生蓝移；在混合溶剂中，由于每种溶剂对聚合物的溶解能力不同，而使两种构象共存于溶液中，因此在不同配比的混合溶剂中，聚合物的吸收光谱发生相应的变化。     

溶剂效应对聚喹啉铝发光特性的影响

研究了非共轭聚喹啉铝（Palq)在氯仿和乙醇不同极性的溶剂下所获得的薄膜的吸收和发光光谱。由于溶剂性的不同，聚喹啉铝链在氯仿和乙醇溶液中表现出不同的聚集状态。当各种溶液分别旋涂成膜时，溶液中的聚喹啉铝的聚集态仍部分地保存下来，导致不同聚喹啉铝薄膜的电子结构状态的差别。结果，聚喹啉铝的薄膜表现出不同的发光特性。实验表明，在制作聚合物器件中，溶剂的选择对共轭聚合物的发光特性有着重要的影响。     

Spectroscopic Properties of Co-Fe Hydrotalcites

The spectroscopic properties of hydrotalcite-like compounds, containing Co(II) and Fe(III) in the layers, have been studied. In these materials, depending on the experimental conditions during synthesis, Co(II) becomes partially oxidized to Co(III). Although the environment of the cations is close to octahedral in all cases, Mossbauer data indicate a more symmetric environment for Fe(III) ions in samples not submitted to hydrothermal treatment. The FT-IR spectra show some distortion of the carbonate anions in the interlayer space.