2-(ω-联苯基多亚甲基)-5-联苯基-1,3,4-二唑的荧光光谱研究

本文测定了双荧光团化合物2-(ω-联苯基多亚甲基)-5-联苯基-1,3,4-二唑及其模型化合物2-甲基-5-联苯基-1,3,4-二唑和2,5-二联苯基-1,3,4-二唑的荧光光谱.对分子内,分子间激基缔合物和激基复合物的形成进行了研究,并对分子构型与形成分子内激基复合物之间关系作了初步探讨.从实验结果得到,亚甲基桥链的碳数为奇数时容易形成分子内激基复合物.     

偶氮苯光致异构化对紫精-曙洪络合的调控

报导了α，ω－偶氮苯，紫精双发色团化合物的合成与性质研究，结果表明偶氮苯的光致顺反异构化以可调控与之相连的紫精与曙红络合行为，其作用程度的强弱与连接两者的亚甲基链的长度有关，借助ＨＮＭＲ通过对构象进行分析解释了上述的研究结果。     

Research on the fluorescence spectra of 2-(ω-biphenylylpolymethylene)-5-biphenylyl-1,3,4-oxadiazole

The fluorescence spectra of bichromophore compounds 2-(ω-biphenylylpolymethylene)-5-biphenylyl-1,3,4-oxadiazole ( 1—4 ) and its corresponding model compounds 2-methyl-5-biphenylyl-1,3,4-oxadiazole ( 5 ) and 2,5-dibiphenylyl-1,3,4-oxadiazole ( 6 ) have been determined. The formation of intra- and intermolecular excimers and exciplexes have been studied. The relationship between the molecular configuration and the formation of intra exciplex have been discussed. From the experimental results, it can be seen that when the number of the carbon atoms of the methylene bridge is odd, intra exciplex is readily formed.     

Aminorhodamine (ARh): A Bichromophore with Three Emission Bands in Low Temperature Glasses

At first glance, aminorhodamine (ARh) is a typical pH responsive fluorescent, rhodamine‐type dye. However, hidden under the typical rhodamine absorption band, ARh has another electronic transition of similar energy, but polarized orthogonal to that of the rhodamine chromophore. This transition—assigned to an arylpyrylium type chromophore contained in the system—is responsible for the sensor action of the dye. ARh is non‐fluorescent, while protonation of a donor amino group turn on a strong rhodamine‐type emission. At low temperature in frozen solution emission from both electronic subsystems of ARh are observed. In order to achieve more complete understanding of the photophysical mechanisms in this type of fluorescent probes, ARh and its protonated counterpart HARh were studied by absorption and fluorescence spectroscopy, computational chemistry, and at low temperatures in solid solution. Results from fluorescence anisotropy and time‐resolved fluorescence spectra establish a bichromophore model and suggest that a remarkable weak coupling between the two nearly isoenergetic excited states in ARh enables the dual emission. All the complicated properties observed for ARh was accounted for by a bichromophore model describing the electronic system of ARh as a bichromophore constituted by a rhodamine and an arylpyrylium subsystem.     

Electron transfer compatible molecular design of benzothiophene-acetophenone bichromophores: a theoretical approach

Computational work has been done for a bichromophore (4MBA) comprising a donor 4-methoxy-benzo[b]thiophene (4MBT) and an acceptor molecule p-chloro-acetophenone (pclA) linked together by a HC=CH bond which shows large hyperpolarizability. The charge transfer in this bichromophoric system is computed by semiemperical theoretical calculation. Ground state and excited state dipole moment difference of the bichromophore 4MBA indicates a large electron transfer probability.     

三氮唑衍生物随pH变化的双稳态性质

本文设计合成了一系列以三氮唑为电子受体的双生色团化合物。光谱研究表明这些分子的发光性质不仅取决于电子转移驱动力,也取决于间隔基和电子给体的尺寸。有些分子的发光在pH1～3范围内发生急剧变化,荧光量子产率相对于pH值的变化是一个双稳体系而具有光控分子开关性质。     

Selective calcium ion sensing with a bichromophoric squaraine foldamer

Several squaraine tethered bichromophoric podand systems 1a-d and a monochromophoric analogue 2 were prepared and characterized. Among these, the bichromophore, 1b, containing five oxygen atoms in the flexible podand moiety was found to specifically bind Ca(2+) in the presence of other metal ions such as K(+), Na(+), and Mg(2+). The selective binding of Ca(2+) is clear from the absorption and emission spectral changes as well as by the visual color change of 1b from light-blue to an intense purple-blue. Benesi-Hildebrand and Job plots confirmed a 1:1 binding between 1b and Ca(2+). Signaling of the binding event is achieved by the cation-induced folding of the bichromophore and the resultant exciton coupling between the squaraine chromophores. The monochromophoric squaraine dye 2 failed to give optical signals upon Ca(2+) binding, due to the absence of exciton interaction in the bound complex. Titration of the folded complex 9 with EDTA released the metal ion from the complex, thereby regaining the original absorption and emission properties of the bichromophore. The squaraine foldamer 1b reported here is the first example of a selective chromogenic Ca(2+) sensor, which works on the principle of exciton interaction in the folded Ca(2+) complex of a bichromophore, the optical properties of which are similar to those of the "H"-type aggregates of analogous squaraine dyes.     

Synthesis and spectroscopic characterization of meso-tetraarylporphyrins with fused phenanthrene rings

A series of meso-tetraaryl porphyrins with fused phenanthrene rings have been synthesized from boron trifluoride-catalyzed Lindsey condensation of phenanthro[9,10-c]pyrrole with various para-substituted arylaldehydes at low temperature. Their structures were characterized by UV-vis, ¹H NMR, and mass spectroscopies. The UV-vis spectra of these compounds showed remarkable bathochromic shift of the Soret band to the wavelength around 577 nm and Q-bands into the near-infrared region.     

Vibronic coupling in asymmetric bichromophores: Theory and application to diphenylmethane

The theory for modeling vibronic interactions in bichromophores was introduced in sixties by Witkowski and Moffitt [J. Chem. Phys. 33, 872 (1960)] and extended by Fulton and Gouterman [J. Chem. Phys. 35, 1059 (1961)]. The present work describes extension of this vibronic model to describe bichromophores with broken vibrational symmetry such as partly deuterated molecules. Additionally, the model is extended to include inter-chromophore vibrational modes. The model can treat multiple vibrational modes by employing Lanczos diagonalization procedure of sparse matrices. The developed vibronic model is applied to simulation of vibronic spectra of flexible bichromophore diphenylmethane and compared to high-resolution experimental spectra [J. A. Stearns, N. R. Pillsbury, K. O. Douglass, C. W. Mu?ller, T. S. Zwier, and D. F. Plusquellic, J. Chem. Phys. 129, 224305 (2008)].     

三种偶氮化合物的荧光光谱研究

近年来 ,一些重要的有机染料探针在生物大分子光度分析、荧光分析和共振光散射分析方面得到了日益广泛地应用[1,2 ] ,深入研究这些有机染料的结构和光谱特性 ,探讨这些有机染料与生物大分子之间的作用 ,对于筛选性能优良的分子光谱探针 ,设计更加灵敏简便的分子光谱检测器件 ,是现代分析化学十分重要的课题。本文测定了偶氮胂Ⅱ (Ａｒｓｅｎａｚｏ)、铬黑Ｔ(ＥｒｉｏｃｈｒｏｍｅｂｌａｃｋＴ)、铬蓝黑 (ＥｒｉｏｃｈｒｏｍｅｂｌｕｅｂｌａｃｋＲ)等 3种化合物的荧光光谱 ,并用量子化学半经验方法ＡＭ1和ＰＭ3对3种化合物分子进行包括构型…     

有机锡化合物的电喷雾电离质谱

报道了一系列有机锡ＲＲＰ（Ｓ）ＳＳｎ（Ｃｙ）３化合物的电喷雾电离质谱（ＥＳＩ－ＭＳ）及碰撞诱导解离质谱（ＣＩＤ－ＭＳ）,总结了其谱图特征,讨论了其碎裂机理,为该类化合物的鉴定提供了依据。     

Synthesis and characterisation of medium-sized ring systems by oxidative cleavage. Part 2: Insights from the study of ring expanded analogues

Variable temperature NMR analysis and computational methods have been used to develop a detailed understanding of the ¹H NMR spectra of a family of medium-sized ring containing compounds. The family consists of analogues containing 10-, 11- and 12-membered rings and in all cases the NMR spectra at room temperature showed a series of diastereotopic methylene signals despite the lack of a stereogenic centre in these systems. On repeating the NMR analysis at higher temperatures, all the signals coalesced for the 12-membered ring system consistent with full interconversion of ring conformers. This was not observed in the analogous 10- and 11-membered ring systems with the interchange of conformers remaining slow on the NMR timescale. However, 1D gs-NOESY/EXSY NMR experiments showed that in the smaller ring systems interconversion of diastereotopic protons did occur. Computational studies suggest that the dynamic process observed by NMR for the 10- and 11-membered rings systems is different from that observed in the 12-membered ring containing compound.     

Photocyclization of 1,2-diaryl- and photobicyclization of 1,2,6-triarylpyridinium cations

New 1,2-diaryl- and 1,2,6-triarylpyridinium salts, containing various five- and six-membered heteroaromatic substituents in the 1, 2, and 6-positions of the pyridinium ring, were synthesized. New tetra- and hexacyclic compounds were prepared by photocyclization of the cations of these salts. Photocyclization proceeds through a singlet excited state with nonadiabatic formation of a dihydro intermediate, followed by its oxidative dehydrogenation. The structure and quantum yield of the formation of photoproducts are determined by steric and electronic effects of the substituents, and in bichromophore compounds by the presence of S-S intramolecular interfragment energy transfer.The article is dedicated to the memory of Professor G. N. Dorofeenko.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1518, November, 1984.     

Identification of unknown compounds using data bases and computer simulation of mass spectra

The possibility of identification based on the comparison of experimental electron-ionization mass spectrum of an unknown (in our case, model) compound with the mass spectra of the candidate compounds generated by the Mass Frontier software has been demonstrated by the example of three model compounds. The structural isomers of the identified substances found in the ChemExper database have been used as the candidate compounds. The candidate substances have been ranged by the degree of similarity between their simulated mass spectra and the experimental mass spectrum of the unknown compound. The mass spectra have been compared on the basis of the algorithm used in the NIST MS Search standard search system. In all three cases, the sought-after structure has been indicated as the most probable one of all the candidate structures.     

Synthesis and properties of novel photochromic bisthienylethenes containing imidazole and imidazolium derivatives

A series of bisthienylethenes containing imidazole and imidazolium derivatives have been prepared and the products have been characterized by means of NMR and MS.Their photochromic and fluorescent switch properties have been investigated by UV–vis absorption spectra and fluorescence spectra.The fluorescent emissions of these kinds of photochromic compounds can be simply modulated by varying the imidazole groups,which shows that these compounds may have potential application in the design of fluorescent photochromic materials.     

硫逐磷酸酯和二硫代磷酸酯的电喷雾电离质谱lectrosprayIon

研究了9种硫逐磷酸酯及二硫代磷酸酯的电喷雾电离 (ESI)质谱并归纳了谱图特征。根据碰撞诱导解离 (CID)的结果 ,讨论了其在ESI质谱的规律。     

Vibrational spectra of cyclobutanecarbonyl chloride and bromide and their α-deuterated compounds

The IR spectra of cyclobutanecarbonyl chloride and bromide and their α-deuterated compounds have been recorded in the vapor, liquid and crystal states. The Raman spectra have also been measured in the liquid state. Comparison of the spectra in the liquid phase with those in the crystal phase reveals that these acyl halides exist in a conformational equilibrium in the liquid state. Tentative vibrational assignments are proposed on the basis of the isotope effect and previous published results for other simple cyclobutane compounds.     

一种合成6或7位乙酰基Lumazine环系衍生物的新途径

标题化合物的合成目的,在于研究其结构与稳定性的关系,用其解释V_b2的生命前合成中某些反应的机理,有关此种化合物的合成文献报道甚少,而且步骤较多。     

飞行时间二次离子质谱(TOF-SIMS)结合化学衍生法分析杂环新化合物的结构

飞行时间二次离子质谱(TOF-SIMS)分析了难挥发的杂环新化合物咪唑啉硫氰酸盐及其三种衍生物, 确认出很强的氢离化及银离化准分子离子峰, 通过对各种衍生物谱图的对照分析, 确认出较强的含有结构特征的碎片离子峰, 并对该化合物在离子轰击下的裂解规律作了分析, 支持了对该新化合物结构的鉴定。     

Photophysical processes involved within the bichromophoric system 9-benzotriazole-1-ylmethyl-9H-carbazole and its role as an artificial photosynthetic device

From both steady state and fluorescence lifetime measurements it reveals that due to photoexcitation of benzotriazole (BZ) part of the bichromophore, 9(1-H-benzotriazole-lylmethyl)-9H-carbazole (BHC), singlet-singlet energy transfer takes place to populate the lowest excited singlet of carbazole (CZ). CZ, thus being excited indirectly via energy transfer process, undergoes strong charge transfer (CT) reaction with the surrounding polar medium acetonitrile (ACN). On the other hand, very weak CT band was apparent when CZ part, within BHC, was directly excited. In less polar tetrahydrofuran (THF) and polar benzonitrile (BN) environment, lack of formation of CT band strongly suggests in favor of the electron-accepting behavior of ACN. Moreover, by measuring the emission spectra of BHC in microcrystals and of 30 bilayers mixed LB film at high mole fraction of BHC molecules, the possibility of excimer formation or aggregation has been ruled out. Thus, BHC, when dissolved in ACN, acts as a triad system of BZ-CZ-ACN where BZ acts as an antenna molecule and CZ as a reaction center. The possible role of the bichromophoric system BHC as an artificial photosynthetic or solar energy conversion device has been hinted.