席夫碱类高选择性氟离子化学传感器的研究

以邻羟基萘甲醛和水合肼合成了席夫碱类化合物荧光黄101(DHNA),在F-存在的情况下,其紫外可见光谱和荧光光谱都发生明显的变化,同时溶液颜色和荧光的变化可以通过肉眼直接观测到.在Cl-、Br-、1-、HSO4-、H2PO4-;等干扰离子存在的情况下,DHNA对F-具有良好的选择性.因此,荧光黄101可用于制备检测F-的高灵敏度颜色.荧光传感器.     

三种邻香兰素还原型席夫碱-镍（Ⅱ）配合物的合成及表征

席夫(Schiff)碱可作为合成螯合物、生物活性剂、分子试剂和催化剂等的中间体[1,2].目前,对还原型席夫碱化合物的研究主要集中在水杨醛类还原型席夫碱,用邻香兰素与氨基酸合成邻香兰素氨基酸还原型席夫碱化合物的研究国内外尚未见报导.     

镝(Ⅲ)离子比色/荧光传感器:杯芳席夫碱的设计与合成

合成了一种新型含杯[4]芳烃的席夫碱类化合物,镝(III)离子的加入使得其溶液的颜色由无色变为黄色,荧光强度降低.而不含杯芳烃空腔的模型化合物加入硝酸镝后溶液颜色没有明显变化.这说明合成的含杯[4]芳烃的席夫碱化合物能够选择性的识别镝(III)离子,可用作分析化学中镝离子的检测.     

铀酰的双席夫碱类配合物的合成与表征

铀酰的双席夫碱类配合物的合成与表征范玉华，毕彩丰（山东建材学院应用化学系济南２５００２２）关键词硝酸铀酰，双席夫碱，配合物过渡金属及稀土金属离子的双席夫碱类配合物已有不少报道，但锕系元素铀酰的邻香草醛或水杨醛二胺类双席夫碱配合物未见报道。为了探讨锕系...     

噻吩-2-甲醛缩L-半胱氨酸席夫碱的合成、晶体结构及量子化学研究

采用噻吩-2-甲醛分别与邻氨基苯硫酚和硫代氨基脲合成了2种噻吩-2-甲醛杂环席夫碱.利用红外光谱、紫外-可见光谱、荧光光谱、X-射线单晶衍射分析、热重分析和核磁共振氢谱等检测方法对2种目标新型杂环类席夫碱产物的结构和性质进行了表征与分析.采用量子化学中常用的密度泛函方法(DFT)对2种新席夫碱化合物进行几何优化,采用单激发组态相互作用(CIS)和含时密度泛函方法(TD-DFT)进一步优化,比较计算光谱与实际测试光谱之间的误差,探究了2种席夫碱化合物荧光发光机制,为这类席夫碱分子结构设计提供了理论依据.     

邻香兰素-氨基酸席夫碱及其配合物对O-2的抑制作用

自从1965年B.Rosenberg等发现顺式 二氯二氨合铂(Ⅱ)能抑制大肠杆菌的细胞分裂、在1969年发现它的抗动物肿瘤活性后,在探索新的有效抗癌药物时,发现席夫碱类化合物有一定的抗癌作用,其金属配合物效果更佳[1,2]。O-2是导致生物体内炎症、衰老和癌变的重要原因之一。我们采用改进的邻苯三酚自氧化法,使用紫外 可见分光光度计对所合成的邻香兰素 丝氨酸席夫碱(L1)、邻香兰素 苏氨酸席夫碱(L2)、邻香兰素 半胱氨酸席夫碱(L3)、邻香兰素 蛋氨酸席夫碱(L4)、邻香兰素 谷氨酸席夫碱(L5)及其过渡金属配合物进行了生物活性测试,得到的结论为…     

靛红席夫碱及其Cu(Ⅱ)/Zn(Ⅱ)配合物的合成与抗稻瘟菌活性研究

以靛红为原料合成了系列席夫碱类化合物及其cu(Ⅱ)、Zn(Ⅱ)配合物,研究了它们在抗稻瘟菌方面的活性,发现靛红及其席夫碱类化合物没有好的抑制稻瘟菌孢子萌发的活性,而其Cu(Ⅱ)、Zn(Ⅱ)配合物具有较好的活性,其中双靛红席夫碱的Cu(Ⅱ)的活性接近Carbendazim的水平。     

2种偶氮席夫碱类化合物的合成及其热致变色性质

摘 要 合成了两种偶氮席夫碱类化合物,通过元素分析,核磁共振氢谱,红外光谱表征了其结构, 经紫外光谱测试表明,这两种化合物具有良好的热致变色性质,在恒定温度下,其trans-cis吸收波长的变化和时间的变化有较好的线性关系。     

席夫碱的合成及热色性研究Ⅲ——二取代苯甲醛-二-对-氨基苯甲烷类席夫碱

本文合成了二取代苯甲醛-二-对-二氨基苯基甲烧类席夫碱类的7个化合物,并应用物理方法进行了表征.通过加热显微观察,这些化合物都具热色性,而其中4种具有可逆热色性.此外应用差热分析阐述了这类席夫碱的吸热峰的ΔH(ΔS)与其结构的关系.     

新型杯[4]席夫碱的合成及光致变色性质研究

合成了三种新型含杯[4]芳烃的席夫碱类化合物及不含杯[4]芳烃空腔的模型化合物, 利用IR, 1H NMR, 13C NMR, MALDI-TOF MS和元素分析对其结构进行了表征. 研究了它们的光致变色性能及杯[4]芳烃空腔、取代基和溶剂对光致变色性能的影响. 结果表明, 杯[4]芳烃、取代基OCH3和CH2Cl2可以改善席夫碱的光致变色性能.     

LIGHT-INDUCED PERTURBATION OF AROMATIC RESIDUES IN BOVINE RHODOPSIN AND BACTERIORHODOPSIN*

Light-induced changes in the UV absorption spectrum of bovine rod outer segment membranes were measured by conventional difference spectroscopy and by flash photolysis methods. Different thermal intermediates of rhodopsin (lumirhodopsin, metarhodopsin I, metarhodopsin II, and meta-rhodopsin III) have absorption spectra in the ultraviolet which differ from the rhodopsin spectrum and from each other. The spectra associated with metarhodopsin I, metarhodopsin II, and metarhodopsin III are characteristic of perturbation of a small number of tyr. and/or trp residues, most likely one trp residue. These aromatic residues are in the neighborhood of the retinal Schiff base and undergo coordinated changes of interaction with retinal during the bleaching sequence. At the metarhodopsin II stage, the magnitude of the UV spectral changes is consistent with the exposure of a previously shielded trp residue to an aqueous environment. The present results are consistent with previous spectral studies which limit the extent of light-induced conformational changes to regions of the protein in the neighborhood of the retinal Schiff base. An analogous study was made on light-adapted purple membranes of Halobacterium halobium. The UV absorption spectrum associated with the deprotonated Schiff base intermediate of the trans-bacteriorhodopsin cycle is indicative, in part, of aromatic residue perturbation. However, significant changes in the secondary and tertiary structures of the bacterio-rhodopsin protein characteristic of a delocalized conformational change are unlikely at this intermediate stage.     

UV-vis, IR and (1)H NMR spectroscopic studies of some Schiff bases derivatives of 4-aminoantipyrine

Five Schiff bases derived from 4-aminoantipyrine and benzaldehyde derivatives (I) are prepared and their UV-vis, IR, (1)H NMR and fluorescence spectra are investigated and discussed. The electronic absorption spectra of the hydroxy 4-aminoantipyrine Schiff bases Ib and Ie as well as the fluorescence spectra of Ie are studied in the organic solvents of different polarity. The UV-vis absorption spectra of 4-aminoantipyrine Schiff bases Ib, Id and Ie are investigated in aqueous buffer solutions of varying pH and utilized for the determination of pK(a) and DeltaG of the ionization process. The reactions of the hydroxy compounds Ib and Ie with Ni(II) and Cu(II) ions are also studied. The results of spectral studies are supported by some molecular orbital calculations using an atom superposition and electron delocalization molecular orbital theory for a compound Ib.     

Synthesis, characterization, and spectroscopic investigation of benzoxazole conjugated Schiff bases

Two Schiff bases were synthesized by reaction of 2-(4'-aminophenyl)benzoxazole derivatives with 4-N,N-diethylaminobenzaldehyde. UV-visible (UV-vis) and steady-state fluorescence in solution were applied in order to characterize its photophysical behavior. The Schiff bases present absorption in the UV region with fluorescence emission in the blue-green region, with a large Stokes' shift. The UV-vis data indicates that each dye behaves as two different chromophores in solution in the ground state. The fluorescence emission spectra of the dye 5a show that an intramolecular proton transfer (ESIPT) mechanism takes place in the excited state, whereas a twisted internal charge transfer (TICT) state is observed for the dye 5b. Theoretical calculations were performed in order to study the conformation and polarity of the molecules at their ground and excited electronic states. Using density functional theory (DFT) methods at theoretical levels BLYP/Aug-SV(P) for geometry optimizations and B3LYP/6-311++G(2d,p) for single-point energy evaluations, the calculations indicate that the lowest energy conformations are in all cases nonplanar and that the dipole moments of the excited state relaxed structures are much larger than those of the ground state structures, which corroborates the experimental UV-vis absorption results.     

The electronic structure,solvatochromism, and electric dipole moments of new Schiff base derivatives using absorbance and fluorescence spectra

Structural Chemistry - The electronic structure and electronic transitions of four new mono Schiff base derivatives are interpreted by using absorption and fluorescence spectra including 28...     

Photophysical processes in aromatic polyimides. Studies with model compounds

Emission mechanism in an aromatic polyimide, PI(BPDA/PDA), derived from biphenyltetracarboxylic dianhydride and p-phenylene diamine were studied with ultraviolet visible absorption and fluorescence spectra of a series of the model compounds. The excitation spectrum of the intermolecular charge-transfer (CT) fluorescence peaking around 550 nm of PI(BPDA/PDA) thin film was completely consistent with the absorption spectrum, indicating that the intermolecular CT fluorescence emission of PI(BPDA/PDA) film is not caused by direct excitation of the CT absorption band, but by light absorption due to structural units in the polymer backbone. The UV-vis. absorption spectra of the model compounds corresponding to the structural units in PI(BPDA/PDA) showed that the longest wavelength absorption band is due to the biphenylbisimide moiety. The band was assigned as π, π* transition with the polarization spectrum of the model compound. The fluorescence spectra of the model compounds changed sensitively depending on the conformation around N-phenyl bond. The lifetime measurement for the model compounds suggested that intramolecular CT process occurs very rapidly. © 1993 John Wiley & Sons, Inc.     

Absorption studies of neutral retinal Schiff base chromophores

The neutral retinal Schiff base is connected to opsin in UV sensing pigments and in the blue-shifted meta-II signaling state of the rhodopsin photocycle. We have designed and synthesized two model systems for this neutral chromophore and have measured their gas-phase absorption spectra in the electrostatic storage ring ELISA with a photofragmentation technique. By comparison to the absorption spectrum of the protonated retinal Schiff base in vacuo, we found that the blue shift caused by deprotonation of the Schiff base is more than 200 nm. The absorption properties of the UV absorbing proteins are thus largely determined by the intrinsic properties of the chromophore. The effect of approaching a positive charge to the Schiff base was also studied, as well as the susceptibility of the protonated and unprotonated chromophores to experience spectral shifts in different solvents.     

Photoinitiated Processes in Molecules of Schiff Bases Having an NH···N Intramolecular Hydrogen Bond

Study of the absorption and luminescence spectra of Schiff bases derived from o-(p-tolylsulfonylamino)benzaldehyde has shown that these systems, like those derived from salicylaldehyde, are characterized by intramolecular proton transfer in the excited and ground electronic states. This process is responsible for the appearance at 77 K of fluorescence with an anomalous Stokes shift and formation of ketone structures. Unlike o-[alkyl(or aryl)iminomethyl]phenols, o-[alkyl(or aryl)iminomethyl]anilines do not give rise to acoplanarization of the ketone fragment, which could follow intramolecular proton transfer in the excited state and is responsible for fluorescence with an anomalous Stokes shift and formation of colored structures.     

3,5-二氯水杨醛缩邻苯二胺铜配合物的合成、晶体结构及光谱学性质

合成了3,5-二氯水杨醛缩邻苯二胺铜配合物[Cu(C₂₀H₁₀Cl₄O₂N₂)]·DMF。 通过元素分析、红外光谱、热重测试技术对其进行了表征,同时用X射线单晶衍射确定了其晶体结构;利用紫外-可见光吸收光谱、荧光激发和发射光谱研究了该配合物的光物理性能。 结果表明,该晶体属于单斜晶系,空间群为P2(1)/n,a=0.81316(8) nm,b=1.53101(18) nm,c=1.87819(19) nm,β=92.4530(10)°,Z=4,最终偏差因子R₁=0.0584,ωR₂=0.1482,配合物的中心铜离子与席夫碱的2个O和2个N配位,形成1个五元环和2个六元环,从而构成了1个四配位的平面构型;配合物的热分解温度为384 ℃,具有很好的热稳定性;在DMF溶液体系中,配合物的荧光激发带位于360～480 nm,荧光发射峰在507 nm处,为蓝绿色荧光,最佳激发波长为440 nm,禁带宽度2.59 eV。     

大环Schiff碱化合物的合成、表征及其荧光活性研究

含乙酰丙酮类大环Schiff碱化合物一般都具有良好的荧光活性．采用模板合成法,用对苯二胺与乙酰丙酮反应合成得到的Schiff碱配体（H2L）与烷基二胺（即1,2-乙二胺,1,3-丙二胺,1,4-丁二胺）反应合成了3种新型大环Schiff碱化合物,通过元素分析,^1H NMR,IR,MS,UV,摩尔电导等手段对合成得到的化合物进行了组成和结构表征,同时在DMF溶液中对大环Schiff碱锌（Ⅱ）配合物的荧光活性进行了初步研究．     

两种新型芴类Schiff碱的合成及其溶剂效应和聚集诱导发光性质

2-氨基-9,9-二甲基芴分别与2-羟基-1-萘甲醛和4-二乙胺基水杨醛经Schiff碱反应合成了两种新型芴类Schiff碱 (4和5),其结构经¹H NMR, ¹³C NMR, ESI-MS和元素分析表征。通过紫外-可见吸收光谱和荧光发射光谱初步研究了4和5的溶剂效应和聚集诱导发光性质。结果表明： 4和5的紫外吸收和荧光光谱受质子性溶剂的影响明显高于非质子性溶剂,同时两者具有良好的聚集诱导发光增强效应。THF-H₂-O体系中含水量分别达到60%和70%时, 4和5的荧光强度最大。