香豆素酮类化合物的磷光光谱

研究了在不同溶剂中测定和在不同波长时激发的香豆素酮类化合物的荧光光谱, 结果明显地指出, 在溶液中呈现出由位阻旋转引起的许多不同的旋光异构体.     

新型咪唑啉酮类化合物的拉曼光谱特性研究

本文研究了四种新型咪唑啉酮类化合物的拉曼光谱,在对拉曼谱峰进行归属的基础上,确定了化合物的空间伸展形态,并对其除草活性的影响因素进行了探讨.     

香豆素酮类化合物的瞬态研究——Ⅲ.香豆素酮和碘鎓盐间的电子转移

本工作采用激光闪光光解法对香豆素酮类化合物敏化碘鎓盐化合物问题进行了研究。结果表明:碘鎓盐化合物能通过电子转移机理猝灭香豆素酮的激发三重态。工作中还用甲基紫精(PQ²⁺)为模型化物,观察到它也能使香豆素酮的三重态猝灭,同时可看到在位于610nm处的PQ⁺生成。这些结果说明,在发生电子转移的反应中香豆素酮是电子给体,按Weller公式的计算结果也表明它们之间可发生电子转移反应。     

冠醚连接的给体-受体化合物中分子内远程三重态能量传递

本文合成了用冠醚连接的二苯酮基(给体)和萘基(受体)的二元化合物,用稳态和时间分辨光谱研究了该化合物分子内远程三重态能量传递,证实当冠醚络合钠离子以后,可以发生有效的分子内远程三重态能量传递,对传递机制进行了讨论。     

若干香豆素衍生物在滤纸基质上的RTP和RTF特性

详细考察了各种基质、重原子微扰剂和实验条件的影响之后,成功地实现了多种香豆素衍生物的室温磷光(RTP)发射。在滤纸基质上,以1mol/L的Pb(Ac)_2作重原子微扰剂时,近20种香豆素衍生物大都能产生较强的RTP发射。而且某些衍生物的RTP强度和λ_(ex)/λ_(em)等特性间呈现出明显的取代基效应。本文还对这些衍生物在滤纸基质上的室温荧光(RTF)和其混和光谱(在重原子微扰剂存在下以荧光方式测得的光谱)等特性作了对比测定,发现其间亦呈现类似的取代基效应。有关香豆素衍生物的RTP特性,迄今尚未报道。这类衍生物RTP发射的实现,预示着它们用作RTP标记物的可能性。     

新型香豆素酮类不对称双光子染料的合成及其光物理性质

本文以二苯乙烯和香豆素为共轭桥,二乙氨基为电子给体,羰基为电子受体,合成了一个具有D-π₁-A-π₂-D结构的香豆素酮类双光子染料C3.用紫外-可见光谱、荧光光谱研究了该化合物的光物理性质.发现在光作用下C3很容易发生分子内电荷转移,进而转变为扭曲的分子内电荷转移,产生很大的偶极矩变化.以飞秒脉冲激光为激发光源,用上转换荧光法测定了其双光子吸收截面.在激发波长为850 nm时,新化合物的双光子吸收截面值达1292 GM,比同系列香豆素酮衍生物C1、C2的双光子吸收截面值高一到两个数量级.     

磷光客体三重态能级对基于PVK主体的电致发光器件的影响

将磷光客体掺入PVK:PBD主体材料中是获得高效率磷光电致发光器件 (PhPLED)的有效途径.然而,分别掺杂Ir(pppy)₃、Ir(F-pppy)₃和Ir(F₂-pppy)₃三种磷光客体的PhPLED器件性能件却显著不同.我们分别模拟主-客体间能量转移和客体直接捕获电子空穴对两种机制,研究了三种客体材料的磷光发射及其衰减过程.研究表明:平衡的载流子注入和客体高效率的载流子捕获是实现Ir-配合物掺杂的PhPLED器件性能优良的主要机制,PVK较低的三重态能级使其无法成为蓝光磷光电致发光器件的主体,在PVK中掺入PBD的方法,则进一步降低了主体材料的三重态能级,这是蓝光磷光电致发光器件运行效率较低的主要原因.本文的研究结果可为高分子磷光电致发光器件的制备技术和新型磷光主体的设计提供参考.     

香豆素酰胺类化合物的合成及光谱特性

用(取代)香豆素-3-甲酰氯(Ⅰa～Ⅰc)和取代2-氨基苯并噻唑(Ⅱa～Ⅱd)作用合成了12种新的目标化合物(Ⅲa～Ⅲl),用HRMS、IR、1H NMR对化合物结构进行了表征,确定了化合物的结构,并对其紫外吸收光谱和荧光光谱进行了分析。研究发现:在紫外光谱中,新化合物(Ⅲa～Ⅲl)和原料化合物(Ⅰa～Ⅰc)相比,因共轭链的增长而使其最大吸收波长(λmax)红移;12种化合物表现出比原料化合物(Ⅰa～Ⅰc)较强的荧光性能。     

Triplet‐sensitized irradiation of a main‐chain liquid crystalline poly(aryl cinnamate) in three different phases

Visible light irradiation of thin films of a main‐chain liquid crystalline poly(aryl cinnamate) using ketocoumarins as triplet sensitizers leads to photochemical crosslinking and UV‐vis and FTIR spectroscopic changes associated with saturation of the cinnamate double bond, most likely by 2 + 2 photocycloaddition. The triplet sensitizers are themselves photolabile and are lost by photochemical reactions during the sensitization process. A new ketocoumarin sensitizer with decyloxy substituents and a reduced tendency to phase separate from the polymer is reported. A simple calculation of the sensitization stoichiometry shows that a single molecule of this ketocoumarin sensitizes the destruction of approximately 90 cinnamate chromophores in the “as cast” films below T_g and about 300 chromophores in the more‐ordered glassy nematic films and in “as cast” films of poly(vinyl cinnamate). Triplet sensitization of fluid nematic films leads, upon initial irradiation, to UV‐vis hyperchromism that is attributed to disruption of chromophore aggregation and, possibly, to disruption of the nematic mesophase as photoproducts begin to form. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 134–144, 2001     

萘酰亚胺及其含二茂铁二元化合物的分子间(内)三重态能量传递

近年来萘酰亚胺类化合物作为超分子体系中的功能单元逐渐引起了人们的重视,如快速响应的光开关体系[1]、生物荧光探针体系[2]、激光染料天线分子[3]等.     

Broadband Visible‐Light‐Harvesting trans‐Bis(alkylphosphine) Platinum(II)‐Alkynyl Complexes with Singlet Energy Transfer between BODIPY and Naphthalene Diimide Ligands

A heteroleptic bis(tributylphosphine) platinum(II)‐alkynyl complex ( Pt‐1 ) showing broadband visible‐light absorption was prepared. Two different visible‐light‐absorbing ligands, that is, ethynylated boron‐dipyrromethene (BODIPY) and a functionalized naphthalene diimide (NDI) were used in the molecule. Two reference complexes, Pt‐2 and Pt‐3 , which contain only the NDI or BODIPY ligand, respectively, were also prepared. The coordinated BODIPY ligand shows absorption at 503 nm and fluorescence at 516 nm, whereas the coordinated NDI ligand absorbs at 594 nm; the spectral overlap between the two ligands ensures intramolecular resonance energy transfer in Pt‐1 , with BODIPY as the singlet energy donor and NDI as the energy acceptor. The complex shows strong absorption in the region 450 nm–640 nm, with molar absorption coefficient up to 88 000 M ^?1 cm^?1. Long‐lived triplet excited states lifetimes were observed for Pt‐1 – Pt‐3 (36.9 μs, 28.3 μs, and 818.6 μs, respectively). Singlet and triplet energy transfer processes were studied by the fluorescence/phosphorescence excitation spectra, steady‐state and time‐resolved UV/Vis absorption and luminescence spectra, as well as nanosecond time‐resolved transient difference absorption spectra. A triplet‐state equilibrium was observed for Pt‐1 . The complexes were used as triplet photosensitizers for triplet–triplet annihilation upconversion, with upconversion quantum yields up to 18.4 % being observed for Pt‐1 .     

对称吡啶双酰胺及其稀土配合物的合成、表征与荧光性质的研究

以元素分析、红外光谱、差热及核磁进行表征了配体及其五种稀土（La^3＋,Eu^3＋,Tb^3＋,Gd^3＋,Yb^3＋）配合物,确定了其组成,研究了部分配合物的固态荧光.同时以低温磷光光谱确定了配体的三重态能级为22989 cm^-1,研究了配体与稀土离子的能级匹配情况,详细讨论了配合物的发光性能.结果发现,铽配合物能发出很强的特有荧光,而铕配合物所发荧光很弱,说明配体L与Tb^3＋ 的^5D4匹配.对于Tb^3＋而言,当2000 cm^-1〈ΔE（T-^5D4）〈3000 cm^-1时,稀土铽离子发出强的荧光;对于Eu^3＋ 而言,ΔE（T-^5D1）超过3000 cm^-1时,则几乎不发荧光.     

THE LOWEST EXCITED TRIPLET STATES OF CODEINE AND MORPHINE AND OF THEIR MOLECULAR SUBUNITS VERATROLE AND GUAIACOL

Abstract— The lowest excited triplet T₁ states of the two alkaloids, morphine and codeine, have been investigated by ODMR and emission spectroscopy. The electronic character of their T₁ states could be determined by comparing the T₁ properties with those of the constituent parts guaiacol and veratrole. The T₁ properties, e.g. phosphorescence spectra, zero-field splitting parameters and triplet sublevel selective decay rates are very similar for the constituent parts and the alkaloids. Thus, in analogy to veratrole and guaiacol, the T₁ state of codeine and morphine is assigned to a ππ* state mainly localized on the benzene ring and the attached alkoxy and hydroxy groups. There is no evidence for a contribution from the other subunits, trialkylamine and unsaturated alcohol, to the T₁ state of codeine and morphine.     

Near-Infrared Photoactive Aza-BODIPY: Thermally Robust and Photostable Photosensitizer and Efficient Electron Donor

We report herein the synthesis of aza-BODIPY substituted with strongly electron-donating p-(diphenylamino)phenyl substituents (p-Ph₂N−) at 3,5-positions. The presence of p-Ph₂N− groups lowers the energy of the singlet excited state (E_s) to 1.48 eV and induces NIR absorption with λ_abs at 789 nm in THF. The compound studied is weakly emissive with the emission band (λ_f) at 837 nm and with the singlet lifetime (τ_S) equal to 100 ps. Nanosecond laser photolysis experiments of the aza-BODIPY in question revealed T₁→T_n absorption spanning from ca. 350–550 nm with the triplet lifetime (τ_T) equal to 21 μs. By introducing a heavy atom (Br) into the structure of the aza-BODIPY, we managed to turn it into a NIR operating photosensitizer. The photosensitized oxygenation of the model compound–diphenylisobenzofuran (DPBF)-proceedes via Type I and/or Type III mechanism without formation of singlet oxygen (¹O₂). As estimated by CV/DPV measurements, the p-Ph₂N− substituted aza-BODIPYs studied exhibits oxidation processes at relatively low oxidation potentials (E_ox¹), pointing to the very good electron-donating properties of these molecules. Extremely high photostability and thermal robustness up to approximately 300 °C are observed for the p-Ph₂N− substituted aza-BODIPYs.     

THE INFLUENCE OF THE NITRO GROUP ON THE DISSOCIATIONS OF SOME AROMATIC ACIDS AND BASES IN THEIR LOWEST EXCITED TRIPLET STATES*

Abstract— –Estimation of lowest excited triplet and singlet state dissociation constants of some nitro-aromatic acids and bases, from shifts in their phosphorescence and absorption spectra, respectively, indicate that intramolecular charge transfer to the nitro group is much more important in the lowest excited singlet state than in the ground or lowest excited triplet states. As a result, the effect of a nitro group on the acidity of the lowest excited singlet state of an acid or base is more exaggerated than that on the ground or lowest excited triplet state of the same compound. Furthermore, the basicity of the nitro group is greatly enhanced in the lowest excited singlet state. On this basis the increased rate of photoreduction of nitrobenzene in acidic solutions is found to be thermodynamically unfeasible in the lowest excited triplet state. Although the reaction is thermodynamically feasible in the lowest excited singlet state, the short lifetime of that state may make the reaction kinetically unfeasible. Rate-Hammett acidity profiles are therefore inadequate to alone establish the mechanism of photoreduction of nitrobenzene.     

竹红菌素作为激发态氧分子的光敏剂的研究

近年来,竹红菌素(Hypocrellin A and B,简称HA和HB)及其衍生物在光疗技术上的应用,尤其是在癌症和艾滋病的治疗上的应用,越来越引起人们的重视[1~8].     

Phosphorescence of aromatic molecules in complexes with crystalline β-cyclodextrin at room temperature

The rate constants for the quenching by oxygen of triplet states of aromatic molecules (naphthalenes-d₈ and-h₈, phenanthrene) forming inclusion complexes with crystalline β-cyclodextrin in water at 290 K are equal to 900–1300 L mol⁻¹s⁻¹. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1450–1453, August, 1997.