Effect of the Electron-Vibrational Interaction on the Second Electron Transition of Tetraazaporphin and Tetraazachlorin Molecules

We have traced the change in the complex structure of the intense 0–0 band of the electronic S ₂ S ₀ transition in the quasi-line absorption spectra (n-octane, 77 K) for individual types of impurity centers in the series of compounds tetraazaporphin–tetraazachlorin–di(tert-butylbenzo)barrelene-substituted tetraazachlorin. It has been concluded that the reason for the appearance of this structure is the interaction of the pure electronic S ₂ state with the vibronic S ₁ states rather than the Franck–Condon manifestation of low-frequency vibrations. Attempts to detect the short-wave S ₂ S ₀ fluorescence for all three compounds were unsuccessful. The reasons for the difference from the case of bacteriochlorin, in which such a fluorescence was observed earlier, are discussed.     

Ultrafast Photophysics of Star-Like Molecules with Benzene and Triazine Core

Static and transient spectroscopic characters of newly synthesized start-like molecules, 1,3,5-tri（10-butyl-3-propenyl-10H-phenothiazine）-benzene （TP3B） and 2,4,6-tri（10-butyl-3-propenyl -10H-phenothiazine）-[1,3,5]triazine （TP3T）, are studied using static, picosecond fluorescence and femtosecond transient absorption spectroscopy. The results show that when the benzene group is in the center, a large conjugation system is formed, while a fast electron-transfer process happens when the center group is triazine.     

合成几种新型吡啶卟啉季铵盐的金属配合物

用已合成且确证其结构的吡啶卟啉季铵盐,合成了它们的金属配合物,通过IR,UV表征了它们的结构.探讨了它们的合成、分离条件及纯化方法.     

Fluorescence Spectroscopy of Polymer Systems Doped with Rare-Earth Metal Ions and Their Complexes

Abstract

There has been an increased attention to explore the possibility of using polymer materials with rare-earth (RE) metal ions and their complexes as potential optical materials due to their capability of exhibiting novel and unusual properties. The fluorescence characteristics of polymer systems doped with RE metal ions and/or their complexes were analyzed and the effects of the doping metal ion/metal complexes as well as nature of the material were discussed. Electron transitions of REs can be manipulated by efficient ligand designs and proper doping into the polymer matrix. Emphasis was especially focused on the accommodation of the metal ion/metal complex in polymer matrix as well as its role in fluorescence. The photochemistry of the fluorescent polymer matrices with RE complexes is expected to open up frontier fields that lie between photophysics and materials science. Recent developments on a new aspect of these technologies related to the fluorescence dynamics in polymer analysis will also be discussed in this present review.     

Effect of Metal Substitution in BSCCO Ceramic Superconductors

The fabrication, electrical, and optical properties of ceramic Bi_2-xM_xSr₂Ca₂Cu₃O_y (where M=Al or Ni and x=0.3) superconductors are described. Resistivity measurements reveal that when Al is partially substituted at the bismuth site in the BiSrCaCuO compound, T _c decreases to 77 K and the nickel-substituted compound shows a T _c of 70 K, compared to the undoped ceramic BiSrCaCuO samples with T _c of 85 K. Infrared reflectance measurements, which cover the 50-4000 cm^–1 range, find that the reflectance from the ceramic samples decreases in the metal-doped samples. The observed phonon modes in the infrared conductivity spectra (obtained by Kramers-Kronig analysis) decrease in strength and some features are completely smeared out. Furthermore some of the modes are observed to shift slightly in the frequency on doping, the change in the T _c and vibrational modes is attributed to destabilization of 2223 phase.     

Hydrogen Complexes of 1,2-Naphthoquinone with Water Molecules in Aqueous Solution and Their Influence on Shifts of Absorption Bands

Optics and Spectroscopy - Optical absorption spectra of 1,2-naphthoquinone in nonpolar (n-hexane) and polar (water) solvents are obtained. It is shown that quantum-chemical time-dependent density...     

Effect of lattice strain on the Debye-Waller factors of Mg, Zn and Cd

Lattice strains in Mg, Zn and Cd powders produced by grinding have been analyzed by X-ray powder diffraction. The lattice strain (ɛ) and Debye-Waller factor (B) are determined from the half-widths and integrated intensities of the Bragg reflections. In all three cases viz. Mg, Zn and Cd, the Debye-Waller factor is found to increase with the lattice strain. From the correlation between the strain and effective Debye-Waller factor, the Debye-Waller factors for zero strain have been estimated for Mg, Zn and Cd. The variation of energy of vacancy formation as a function of lattice strain has been studied.     

Photophysics of the Lanthanide Complexes with Conjugated Carboxylic Acids by Low Temperature Fluorescent Spectroscopy

In the context, some lanthanide (Eu³⁺, Tb³⁺ and Sm³⁺) complexes with conjugated carboxylic acids (pyridine-carboxylic acids derivatives) have been synthesized and characterized. The low temperature fluorescent spectra for these complexes have been measured at nitrogen atmosphere (77 K), indicating that the central Ln³⁺ ions locate in an equivalent coordination environment with low symmetry for most of these lanthanide complexes belonging to dimeric or polymeric structure. Therefore, the electronic dipole transition (supersensitive transition) (⁵D₀ → ⁷F₂ for Eu³⁺, ⁵D₄ → ⁷F₆ for Tb³⁺, ⁴G_5/2 → ⁶H_9/2 for Sm³⁺) and magnetic dipole transition (⁵D₀ → ⁷F₁ for Eu³⁺, ⁵D₄ → ⁷F₅ for Tb³⁺, ⁴G_5/2 → ⁶H_5/2 for Sm³⁺) show the regular change in the corresponding split number of fluorescent spectra, which can be realized to predict the fine structure of lanthanide complexes.     

邻酚醌水合肼腙及其金属配合物的合成与性能

本文合成了4,5－二羟基－1,2－二水合肼腙及其与若干金属离子的配合物,并运用红外光谱和热重分析法进行了结构表征。并进行了植物生长试验。结果表明,邻苯二酚二水合肼腙是一种高效的植物生长调节剂。     

Effect of Gamma Radiation on the Electrical Resistivity of Some Metal Acetylacetonate Complexes

The effect of gamma radiation on the electrical resistivity of some lanthanide and alkali acetylacetonate complexes was studied for differet doses (20-49 – 36-2 Mr). The activation energy for each complexes was calculated. The obtained results showed that the resistivity as well as the activation energy increase with increasing the radiation dose. An empirical linear relation between the rate of change of resistivity with radiation dose and the ionic radius of the metal was obtained.     

Laser-Induced Flourescence Excitation Spectroscopy and Photophysics of Naphthalene Bichromophoric Molecules in Supersonic Jets

We present studies of interchromophore interactions under supersonic jet conditions in a large number of dinaphthyl bichromophoric molecules by measuring their laser-induced fluorescence (LIF) excitation spectra. The molecules are composed of two naphthalene chromophores connected by an n-methylene bridge. The length of the bridge was varied as a function of the number of methylene units (n = 0, 1, 2, 4, 6), of the general type NnN(i,j), were N denotes naphthalene moiety, n the number of methylene units in the bridge, and (i,j) are the or positions of the bridge at each of the chromophores. We obtained high-quality LIF spectra of these bichromophoric olecules. In the molecules N1N(2,2), N1N(1,2), N2N(2,2), and N2N(1,2), the spectrum is characterized by an intense 0–0 region, with series of low-frequency progressions. These progressions are assigned as vibrational modes of the bridge. The appearance of several series of progressions is explained either by the excitation of different chromophores (in the mixed molecules) or by the excitation of different populated conformers. The spectrum of N4N(1,1) is different in several aspects from these spectra. The origin is shifted farther to the red, to 31,402 cm^–1. Low-frequency progressions or other transitions are not observed near the origin, but typical intrachromophore naphthalene vibrations are intense. The spectra of N6N(1,1) and N6N(2,2) are also characterized by intense intrachromophore vibrations, however, the spectrum of N6N(2,2) is very complicated due to many populated conformations, while that of N6N(1,1) is more simple.     

十八胺缩水杨醛席夫碱过渡金属配合物的合成、表征及抑菌活性

通过选用十八胺与水杨醛缩合形成十八胺缩水杨醛席夫碱,合成出4种过渡金属席夫碱配合物.利用元素分析、红外光谱、摩尔电导、紫外光谱、荧光光谱测定了其组成和结构.利用生物活性实验测定其抑菌活性,结果表明4种配合物对金黄色葡萄球菌、大肠杆菌、枯草杆菌均有不同程度的抑菌作用.     

D-氨基葡萄糖金属配合物对DNA作用的谱学研究

合成了d－氨基葡萄糖金属配合物Cu(Ⅱ）,Zn（Ⅱ）Ni（Ⅱ）,Fe（Ⅲ）,Co（Ⅲ）金属配合物,并用电子吸收光谱,荧光光谱、表面增强拉曼光谱（SERS）研究了它们与DNA的相互作用。探讨了它们与DNA的作用方式,发现它们在银胶上的吸附方式基本相同,因而有相似的SERS,其中CuGlu,Co（Ⅲ）Glu作为抗癌药物有进一步研究的价值。     

镁含量和热处理对Zn1-xMgxO薄膜结构和发光性能的影响

采用溶胶-凝胶工艺在玻璃衬底上制备了Zn1-xMgxO(x=0.1,0.2,0.3,0.4,0.5,0.6,0.7)薄膜.X射线衍射谱(XRD)测试结果发现,在0.1相似文献   

混杂配体金属簇合物的分子振动光谱与结构

由于原子簇化合物在催化，生物活性，功能材料等方面所呈现的重要性，使其成为无机和物理化学最重要的研究领域之一。文章中和谱学方法对一些具有混配体的过渡金属簇合物的结构及其两者之间的关系进行.     

Examination of Polymeric Azomethine Compounds and Their Transition Metal Complexes by Using XRF and XRD Technique

In this study,the electronic transition properties and structural analysis of the metal complexes(Ni(Ⅱ),Co(Ⅱ),Cu(Ⅱ)and Mn(Ⅱ))of three different polymer ligands were performed by using XRF and X-ray diffraction(XRD)techniques,respectively.The structural analysis of the polymers and their complexes were performed by XRD technique and some of the polymers were found to be in the face-centred cubic(fcc)structure.In addition,the values of the present K X-ray intensity ratios are significantly greater than the values reported in literature.     

Conformational Dynamics in Excited States and Photophysical Properties of Meso-Substituted Nitro Derivatives of Octaethylporphyrin and Their Zn Complexes

Optics and Spectroscopy - Using the density functional theory methods, quantum chemical calculations of the excited states of monosubstituted and disubstituted meso-nitro derivatives of...     

金属纳米锥表面吸附分子分布的数值模拟

在均匀外电场中,将吸附在由过渡金属基底生长的纳米锥颗粒表面的CO分子等效为偶极子,在考虑偶极子与局域电场,偶极子之间色散力及偶极子与锥表面原子之间三种相互作用的情况下,给出各相互作用能的数学模型,并用Monte Carlo方法进行数值模拟,得到纳米锥颗粒表面吸附CO分子的空间分布构型.结果表明,在这些相互作用下,纳米锥表面吸附CO分子产生局部凝聚,且随着纳米锥角的变小,吸附在锥顶部的分子更加密集,导致吸附分子间相互作用更强,为解释纳米结构表面吸附体系的异常红外效应提供依据.     

New Insights on the 7-azaindole Photophysics: The Overlooked Role of Its Non Phototautomerizable Hydrogen Bonded Complexes

In this paper we explore the formation and the photophysical properties of the scarcely studied open hydrogen bonded aggregates of 7-Azaindole, 7AI. Thus, we have analyzed the influence that the increase of the 7AI concentration and the decrease of the temperature have on the 7AI photophysics. To help the interpretation of the results, the 7AI-Pyridine system has been used as the model for the analysis of the photophysical properties attributable to the open N_pyrrolic ? HN_pyridinic hydrogen bonded aggregates. Also, the hydrogen bond interactions have been studied by means of the atom in molecule approach from the Bader theory. Experimental and theoretical results support that the formation of open hydrogen bonded aggregates, (?7AI-)_n with n?≥?2 can efficiently compete with that of the profusely studied centro-symmetric cyclic dimer (7AI)₂. Moreover, these aggregates suffer a proton-driven electron transfer process that strongly quenches their room temperature fluorescence and, therefore, masks their presence in the 7AI solutions. Therefore, because most of the studies on the 7AI photophysics have been interpreted without considering the existence of such aggregates and, more important, ignoring its quenching process, many conclusions obtained from these studies should be carefully revised.