Influence of solvent on the physical and lasing properties of dye-doped sol-gel host

Pyrromethene 597 dye is synthesised in two routes by sol-gel process and ethanol and tetrahydrofuran are used as solvents for hydrolysis. To understand the role and the influence of solvent in sol-gel host, absorption and emission spectra of the dye diluted in ethanol and tetrahydrofuran are recorded. Similarly, the absorption, emission spectra and their lasing performance of the molecule obtained by both sol-gel host matrices are also measured and compared. It is shown that the gelation of sol-gel with tetrahydrofuran is faster than that with ethanol. Effect on absorption and emission spectra due to influence of solvent are observed. The lasing performance of pyrromethene 597 dye doped in sol-gel was measured and the output properties are shown and found to be different.     

Photocharacterization of Novel Ruthenium Dyes and Their Utilities as Oxygen Sensing Materials in Presence of Perfluorochemicals

Photophysical constants of three novel ruthenium dyes derived from tridentate pyridinediimine (pydim) ligands has been declared and their photoluminescent properties were investigated in solvents of dichloromethane (DCM), tetrahydrofuran (THF) and ethanol (EtOH) by UV-Visible absorption, emission and excitation spectra. The quantum yield, fluorescence decay time, molar extinction coefficient and Stoke’s shift values of the novel ruthenium complexes were determined. The perfluoro compound (PFC) nonadecafluorodecanoic acid which is also known as medical gas carrier has been used for the first time together with newly synthesized Ruthenium complexes in ethyl alcohol. The utilities of oxygen sensing materials were investigated in EtOH in presence of chemically and biochemically inert PFC.     

Solvent Polarity and Excitation Wavelength Dependence of the Dual Fluorescence in N,N-Diethyl-4-Nitrosoaniline

Dual fluorescence in N,N-Diethyl-4-nitrosoaniline (DENA) has been studied employing absorption, excitation and emission spectroscopic techniques and computational methods. The absorption and fluorescence spectra of DENA were measured in solvents of various polarities at room temperature. The emission spectra of DENA were found to exhibit a single emission band in non polar solvent (cyclohexane) and in a highly polar solvent (acetonitrile). In the contrary, two emission bands were observed in medium polar solvents (tetrahydrofuran, 1,2-dichloroethane and dichloromethane) whereby the short (local excited; LE) and long (charge transfer; CT) emission maxima correspond to the emission maxima of the compound observed in cyclohexane and acetonitrile solutions, respectively. Moreover, the two emission bands have shown strong excitation wavelength dependence, and area normalization resulted in an iso-emissive point. The two emission maxima were in addition found to correspond to two excitation maxima in 3D fluorescence spectra. Further, two minima were obtained in potential energy surface calculation of DENA. From the experimental and computational results it was concluded that the dual fluorescence may be attributed to the presence of two different ground state structural conformers of DENA in equilibrium that are stabilized through solute-solvent interaction.     

抗菌素阿莫西林荧光分析法的研究

本文提出了阿莫西林（２Ｓ,５Ｒ,６Ｒ）－３,３－二甲基－６（Ｒ－）－（１）－２－氨基２－（４－羟基苯基）乙酰氨基－７氧化－４－硫杂－１氮杂双环（３,２,０）庚烷－２－甲酸三水化合物荧光分析的方法。并对影响阿莫西林荧光性质（光谱和光谱强度）的各种因素,包括ｐＨ值、表面活性剂的增效作用、无机离子的配合作用以其他介质条件等进行了较为详细的研究。实验结果表明,阿莫西林具有良好的荧光性质,在微碱性条件下荧光     

激发态质子转移分子2-(2'-羟基苯基)苯并噻唑在不同溶剂中的光谱特性

观测了2-(2’-羟基苯基)苯并噻唑(HBT)在不同极性溶剂中的吸收光谱和荧光光谱,详细研究了溶剂极性对HBT发生激发态分子内质子转移(ESIPT)影响的机制。吸收光谱表明在常态条件下,HBT在各种溶剂中都以烯醇式构型和酮式构型共同存在,但以烯醇式构型占绝大多数。荧光光谱表明在纯环己烷溶剂中,HBT被紫外光激发时,绝大多数烯醇式构型发生ESIPT转变为酮式构型,分子的ESIPT效率最大。在含有乙醇的极性溶剂中,HBT烯醇式会形成溶剂化的烯醇式构型,阻碍分子发生ESIPT反应。溶剂中乙醇含量愈多极性愈强,溶剂化烯醇式的成份就愈多,HBT的ESIPT效率就愈低。以400 nm光激发HBT溶液时,在510 nm处发现酮式构型荧光,从而确认了400 nm处的弱吸收是酮式构型的吸收;且在436和456nm处还有新的荧光峰,分析其可能来源于酮式构型去质子化阴离子的发射。     

激发态质子转移分子2-（2′-羟基苯基）苯并噻唑在不同溶剂中的光谱特性

观测了2-（2′-羟基苯基）苯并噻唑（HBT）在不同极性溶剂中的吸收光谱和荧光光谱,详细研究了溶剂极性对HBT发生激发态分子内质子转移（ESWT）影响的机制。吸收光谱表明在常态条件下,HBT在各种溶剂中都以烯醇式构型和酮式构型共同存在,但以烯醇式构型占绝大多数。荧光光谱表明在纯环己烷溶剂中,HBT被紫外光激发时,绝大多数烯醇式构型发生ESIPPT转变为酮式构型,分子的ESIPT效率最大。在含有乙醇的极性溶剂中,HBT烯醇式会形成溶剂化的烯醇式构型,阻碍分子发生ESIPT反应。溶剂中乙醇含量愈多极性愈强,溶剂化烯醇式的成份就愈多,HBT的ESIPT效率就愈低。以400nm光激发HBT溶液时,在510nm处发现酮式构型荧光,从而确认了400nm处的弱吸收是酮式构型的吸收;且在436和456nm处还有新的荧光峰,分析其可能来源于酮式构型去质子化阴离子的发射。     

脱氢枞酸基D-A型分子的合成、空间构型及光谱性能

对三苯胺进行溴代和C-N偶联反应合成4-萘基三苯胺(a),对脱氢枞酸进行酯化、溴代、硝化、还原和C-N偶联反应合成13-[N,N-(4-萘基苯基)-苯基]胺基-脱异丙基脱氢枞酸甲酯(b)及13-[N,N-双(4-萘基苯基)]胺基-脱异丙基脱氢枞酸甲酯(c)两个化合物,通过1H MNR,13C MNR及MS对化合物的结构进行表征。为了研究化合物结构与光谱性能之间的关系,首先利用Gaussian 09程序采用密度泛函DFT/B3LYP方法,对三个化合物的空间构型进行全优化,得到它们的键长、键角和二面角,对比发现脱氢枞酸骨架和萘环的引入会影响化合物的共平面性,而萘环的引入会增大化合物的共轭程度。光谱性能方面,研究了三种化合物在甲醇、二氧六环、四氢呋喃、二氯甲烷和环己烷这5种极性逐渐减小的溶剂中的荧光发射光谱和紫外吸收光谱。结果表明,在荧光光谱中,化合物a,b和c在不同极性溶剂中最大荧光发射波长均有不同程度位移,在甲醇中最大,在环己烷中最小,但是位移并非随着极性的增大而只发生红移,在二氯甲烷、四氢呋喃和二氧六环3种极性依次增大的溶剂中,a,b,c的荧光发射波长均随着溶剂极性的增大而发生较大程度的蓝移;在同一溶剂中,化合物b和c相对于a的荧光发射波长依次发生红移,c的红移程度与b差距不大。紫外吸收光谱中,三个化合物在不同极性溶剂中的最大吸收波长也有差异,在200～250 nm区间,三个化合物均在二氯甲烷中有较大位移,在300～350 nm区间,在甲醇中位移较大,而在250～300 nm区间,最大吸收波长差别不大;在同一溶剂中,它们在300～350 nm区间的最大吸收波长差别较大,化合物c较a红移26 nm。结合结构优化所得数据可以证明,化合物的共轭程度对荧光发射光谱和紫外吸收光谱均有影响,而共平面性对荧光发射光谱影响较大。化合物a,b和c在不同极性溶剂中荧光发射光谱和紫外吸收光谱的较大变化,表明它们有明显的溶致变色行为,具有作为分子探针探测外部环境极性大小的潜能。     

有机溶剂中水的分光光度法测定

在有机溶剂中有水存在时 ,氯醌酸发生离解 ,其最大吸收波长发生红移 ,且吸收强度显著增加。详细地研究了氯醌酸变色机理及其用于测定水的最佳条件 ,建立了一种新的测定有机溶剂中水含量的分光光度分析方法。测定了白酒、食用酒精与试剂无水酒精中的水含量 ,得到满意测定结果。测定线性范围为φ(H2 O) 0 0 2 %～ 10 % ,方法简单、灵敏度高、重现性好。对甲醇、异丙醇、丁酮、丙酮、乙腈、四氢呋喃中水的测定进行了实验 ,得到了相应的吸光度与浓度校准曲线     

环丙沙星的光谱性质、质子化作用与荧光量子产率

研究了环丙沙星(ciprofloxacin, CIP)在不同pH条件下的荧光光谱、紫外吸收光谱和质子化作用,测量了CIP在中性条件下的荧光量子产率。在H+浓度大于1 mol·L-1的HCl介质中,CIP分子(简写为HL)可以结合3个质子而以H₄L3+形式存在,有微弱的荧光,最大荧光发射波长(λ_ｍａｘ)为456 nm。在pH 0～2的酸性条件下,CIP主要以H₃L2+形式存在,λ_ｍａｘ为450 nm,荧光较弱,荧光强度随pH的升高而上升。在pH 2～4时,CIP主要以H₂L+形式存在,具有强荧光,λ_ｍａｘ仍为450 nm。当pH＞4时,λ_ｍａｘ逐步蓝移到414 nm,荧光强度随pH的升高而稍有降低,同时紫外吸收光谱也有明显变化,表明H₂L+随pH升高而失去质子,以双极离子HL形式存在。当pH＞8时,荧光强度随pH升高而减弱至消失,表明HL逐步失去质子,转化为无荧光的阴离子L-。在分子形态变化过程中,最大荧光激发波长始终在275 nm附近,但最大荧光发射波长有较大变化。在pH 7.0的缓冲溶液中,以硫酸奎宁为参比,测得CIP在最大荧光激发波长275 nm处的荧光量子产率为0.12。     

Spectral Investigations of Solvatochromism and Preferential Solvation on 1,4-Dihydroxy-2,3-Dimethyl-9,10-Anthraquinone

Solvatochromic and preferential solvation of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone (DHDMAQ) have been investigated using optical absorption and fluorescence emission techniques. Optical absorption spectra of DHDMAQ in different solvents show the intra molecular charge transfer band in the region 400–550nm. The observed blue shift with solvent polarity indicates the delocalisation of the excited state, owing to reduction in quasiaromaticity of the chelate rings formed by intra molecular hydrogen bonds, due to electrostatic or hydrogen bonding interaction. This is also confirmed by the observed low oscillator strength and the transition dipole moment. The observed quantum yield of DHDMAQ in different solvents is due to the inter molecular hydrogen bond in the excited state in addition to the intra molecular hydrogen bond. It also reveals from the low oscillator strength, which indicates that the radiative decay is low. Excited state dipole moment of DHDMAQ is calculated by solvatochromic data and it shows a lower value than ground state dipole moment. The preferential solvation parameter shows that in dimethyl formamide (DMF) + ethanol mixture, the DHDMAQ is preferentially solvated by ethanol in DMF rich region and by DMF in ethanol rich region. In the case of DMF + dichloromethane mixture DHDMAQ is preferentially solvated by DMF.     

Synthesis and Spectroscopic Studies of 3,6-Diphenyl-2,5-Dihydropyrrolo[3,4-C]Pyrrole-1,4-Dion’s N,N’-Dialkyl Derivatives

3,6-diaryl-2,5-dihydro-1,4-diketopyrrolo[3,4-c]pyrrole-1,4-dione (DPPD) derivatives are used commercially as red pigments, because of their color strength, brightness, and very low solubility in most common solvents. These products, although highly colored, appear to be of limited value as dyes, since they show a tendency to form an aggregate when incorporated into a solvent. Monoalkyl and dialkyl derivatives of DPPD were synthesized and then characterized with IR, ¹HNMR, UV-Vis absorption and emission spectroscopy. Molar absorption coefficient, singlet energy level and Stokes’ shift values of DPPD derivatives were declared. Monoalkyl and dialkyl derivatives of DPPD’s solubilities were measured from saturated solutions of dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane (DCM), acetonitrile (ACN) and toluene and they are compared with each other.     

快速测定植物叶片叶绿素含量方法的探讨

本文应用分光光度法研究了3种提取溶剂对测定植物叶片叶绿素含量的影响。结果表明，用不同提取溶剂提取叶绿素，提取液吸收光谱相似。其中丙酮-乙醇提取法速度快，叶绿素得率高、稳定性好，精密度高，并提出了一种快速测定叶绿素含量的方法。     

借助功能阳离子实现敏化发光的铕配合物的溶剂效应的研究

在离子缔合型铕配合物Eu(tta)₄·DEASPI中,借助功能阳离子DEASPI的电荷转移激发态可以实现对铕离子的单光子与双光子的敏化发光,其能量传递遵循Förster机制。将Eu(tta)₄·DEASPI溶解于多种有机溶剂中(丙酮、DMF、乙醇和乙腈),发现溶剂效应对于该能量传递体系的影响非常显著。借助光谱测量,发现在乙腈溶液中能量传递效率远高于其他三种溶剂。本文对造成溶剂效应的多种因素进行了详细的分析。     

氧氟沙星的荧光光谱与质子化作用研究

研究了氧氟沙星(Ofloxacin,OFL)在不同pH条件下的荧光光谱、紫外光谱和质子化作用。在强酸性溶液中,OFL分子可以结合两个质子而以三元酸H₃L2+的形式存在,最大荧光发射波长(λ_max)为505 nm。随着pH值升高,OFL的荧光光谱发生变化,在激发光谱中352 nm 形成一等荧光点,同时在紫外吸收光谱中出现等色点,这一光谱特征表明H₃L2+逐渐失去4位C羰基氧结合的质子。在pH 2.5～4范围内,OFL以H₂L+形式存在,λ_max为499 nm。当pH＞4时,随pH值升高,位于499 nm 的荧光发射峰逐渐蓝移至455 nm,在484 nm形成一等荧光发射点,表明C-3位羧基质子的离解。在pH 7左右,OFL以双极离子HL形式存在,λ_max为455 nm,是最强的荧光型体。当pH＞8时,随pH值升高,λ_max由455 nm红移至约475 nm,同时荧光强度下降,表明HL失去哌嗪环N-4上结合的质子。当pH＞10时,OFL以阴离子L-形式存在, 荧光强度随pH值升高而降低,但λmax基本不变,表明介质环境对OFL的荧光性质有一定影响。     

番茄红素的紫外可见光谱和荧光光谱分析

研究了番茄红素在不同溶剂中的紫外可见光谱图,对结果进行分析后发现番茄红素在正己烷、石油醚、丙酮、乙酸乙酯具有较低折光率的溶剂中的特征吸收带波长非常接近,但在较高折光率的溶剂苯、二硫化碳中的特征吸收带与以丙酮作为溶剂相比有不同程度的红移。番茄红素溶于丙酮与水的混合溶剂,当丙酮与水的体积比达到3∶2时,吸收光谱在紫外区出现一新的吸收峰,在可见区吸收光谱的精细结构消失。用荧光光度计采集不同溶液的番茄红素的荧光光谱,番茄红素的荧光峰位于580—590nm,在极性溶剂中荧光发射增强。     

Self—assembly behaviour of amphiphilic diblock copolymer in selective solvents studied by synchrotron small—angle x—ray scattering

The aggregation behaviour of styrene-vinyl benzoic acid (PS_m-b-PVBA_n) amphiphilic diblock copolymers in selective solvents with different m and n was investigated by synchrotron small-angle x-ray scattering (SAXS). We have carried out a detailed analysis of scattering intensity, dimension, shape and microstructure of the diblock copolymers of narrow distribution in water, methanol, ethanol and isopropanol selective solvents, respectively. We have found that the aggregation behaviour of the copolymer depends on the nature of the solvent and the micelle forms flat disc objects with the ratio of radius ω=0.4. The average radius gyration R_g of the copolymer decreases as solvents change from isopropanol to ethanol and to methanol, and increases with increasing pH in aqueous solution, but decreases with the addition of CoCl_2 in ethanol solvent. The scattering intensity of diblock copolymer micelle follows I(h)∝h^{-α} in different selective solutions, suggesting that the PS_m-b-PVBA_n coils have self-similar structure behaviour or a fractal structure in the selective solvents. All of these revealed that the aggregation behaviour of the diblock copolymer changes dramatically with experimental condition in the selective solvent. The increase of mass fractal dimension (D_m) from 2.12 to 2.47 indicates that the copolymer chain changes from a swollen coil to a rather compact disc in the course of changing solvents, decreasing surface fractal dimension (D_s) from 2.98 to 2.58 indicates that the copolymer micelle change from a rather rough surface to a smooth form in the course of increasing pH in aqueous solutions, and increasing D_m and D_s from 2.29 to 2.35 and 2.70 to 2.90, respectively, indicates the shrinkage of copolymer micelle to a rather compact and rough disc form by adding CoCl_2 in ethanol solvents.     

醋酸N-正辛基吡啶离子液体在不同溶剂中的荧光光谱分析

离子液体具有熔点低、可忽略的蒸气压、电化学窗口宽、热稳定性高和良好的导电性等独特性能,引起了化学工业和相关领域的广泛关注。离子液体具有低蒸气压,不会造成空气污染,但这并不意味着它们对环境完全无害。大多数离子液体易溶于水,可能会因为意外泄漏或通过污水进入水生环境。常用离子液体[BMIM][PF₆]和[BMIM][BF₄]的水溶液中,很容易形成氢氟酸,磷酸,具有一定的腐蚀性。将离子液体列为绿色溶剂,也需要提供其关于代谢和降解的毒性、生态毒性研究数据,或者其对环境影响的数据,离子液体在不同溶剂中的检测方法是非常重要的。离子液体的光谱分析法用量较少、方法简单、结果准确。离子液体和许多有机溶剂互溶,可形成均一、稳定的溶液。荧光检测法具有灵敏度高,选择性好,线性范围宽和受外界干扰少等优点。本工作研究了醋酸N-正辛基吡啶（OP-OAc）离子液体在水、乙醇、乙腈、乙酸等4种溶剂中的荧光光谱。研究结果表明,OP-OAc离子液体在不同溶剂中的荧光强度：I_乙酸＞I_乙腈＞I_乙醇＞I_水;最大发射波长的大小顺序：λ_{em, 水}＞λ_{em, 乙醇}＞λ_{em, 乙腈}＞λ_{em, 乙酸};它们的最大发射波长相对于激发波长发生红移;水中OP-OAc的荧光强度与浓度存在较高的相关性;当加入的甲醇、乙醇、乙腈溶剂不断增加时,OP-OAc离子液体的荧光强度增加,溶剂与水的比例为8∶2时,OP-OAc离子液体的荧光强度最强,溶剂的比例超过80%时,荧光强度突然降低;水中OP-OAc离子液体在pH 10时,荧光强度最高,在pH 14时,荧光强度最低。     

Electrospun cross linked rosin fibers

In this study, we describe the first reported preparation of rosin in fiber form through use of an electrospinning technique utilizing various solvent systems. The polymer concentration of the formed fiber was studied by using various solvents such as chloroform, ethanol, N-N dimethylformamide (DMF), tetrahydrofuran (THF), acetone, and methylene chloride (MC). An electrospray of the solution resulted in the beaded form of the rosin. By varying the polymer concentration with MC, we were then able to obtain uniform fibers. However, the fibers exhibited large diameter. We believe that it is possible to reduce the diameter of the rosin fibers through appropriate selection of electrospinning parameters. In addition, the morphological transitions from beads, to beaded fiber, to fiber were studied at different polymer concentrations. We propose a possible physical cross linking mechanism for the formation of rosin fibers during the electrospinning process. Our results demonstrate the feasibility of producing fiber nanostructures of rosin by using an electrospinning technique.     

不同溶剂中苯酚的紫外光谱

主要研究苯酚在不同的溶剂中的紫外光谱。结果发现,苯酚紫外光谱的两个强吸收峰在碱性溶剂中会发生红移,分别从210nm红移至234nm、270nm红移至287nm,而在酸性溶剂中则无明显变化,溶剂极性对两个吸收峰强度也有影响。     

Effect of pure and mixed solvents on the solubility, crystal growth and morphology of ethyl p-dimethylamino benzoate (EDMAB): An organic nonlinear optical material

The effects of pure and mixed solvents of ethanol and acetone on solubility, nucleation and growth of ethyl p-dimethylamino benzoate (EDMAB) were investigated. It was found that solubility of EDMAB increased as the volume ratio of acetone increased in the mixed solvent. Growth experiments were performed at 32 °C using pure and mixed solvents with different volume ratios of ethanol and acetone. Bulk single crystals of EDMAB were grown-in the experiment conducted using mixed solvent of 25% acetone and 75% of ethanol, whereas thin platelet crystal of EDMAB was obtained in the experiment conducted using pure ethanol. The acetone rich system resulted in uncontrolled nucleation with large number of tiny crystals, possibly due to high vapor pressure of acetone. The grown crystals were subjected to various analytical studies such as powder X-ray diffraction, Vickers microhardness, dielectric studies as a function of frequency and optical transmission and the powder Kurtz method.