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有机光电功能材料的宏观性能不仅只依赖于基元分子自身的理化性质,还取决于其分子聚集行为和聚集态结构。在特定的聚集态结构中,分子间弱相互作用的加和与协同,可促进体系性能的拓展与质变,获得超越分子本征属性的功能。这凸显出当前化学研究逐步从关注单分子向分子聚集态科学转变,体现出分子聚集态研究的重要性。本文借助有机室温磷光性能对分子聚集态结构的高度灵敏性与响应性,系统探讨了分子聚集态结构的形成规律与核心影响因素。以此为基础,进一步拓展分子聚集态研究的应用领域,包括力致发光、有机二阶非线性光学、力致变色、有机发光二极管等,从静态调控到动态刺激响应(刺激源:力、热、光、电场等),从单一结构到多组分体系与器件,同时,确立了各种有机光功能材料的优势分子聚集形式,提出了聚集态调控的有效策略与研究思路,阐述了光电功能材料体系设计与合成的可控性与预见性。 相似文献
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芳香酮与芳香醛及芳香胺的Mannich反应 总被引:6,自引:0,他引:6
醛、酮与芳香醛及芳香胺的 Mannich 反应,文献[1]曾报道在 HCl-EtOH 溶液中苯乙酮及甲醛与芳香胺的 Mannich 反应。本文在此基 相似文献
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稀土与酸性萃取剂形成的溶液聚集态结构 总被引:7,自引:0,他引:7
用Fourier变换红外光谱(FT—IR)和光子相关光谱(PCS)研究了皂化的有机磷酸酯类萃取剂和环烷酸萃取剂在正庚烷或正庚烷与2-辛醇的混合溶剂中所形成的聚集物,以及萃取稀土元素后有机相聚集物的变化.结果表明,有机磷酸酯在正庚烷中皂化后形成反向胶团((?)_h<5.0nm),其平均流体力学半径与萃取剂分子的长度相当;2-辛醇的加入可增大反向胶团的粒径.环烷酸皂化后能在混合溶剂中形成W/O型微乳状液(5.0 nm<(?)_h<100 nm).皂化萃取剂萃取稀土元素后,有机相中形成不稳定的聚集物,继而产生聚凝.讨论了聚凝过程的可能机理. 相似文献
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芳香酮的高效对映选择性转移氢化 总被引:2,自引:0,他引:2
手性芳香醇在制药工业上有重要的应用,因而利用芳香酮的对映选择性氢化制备相应的手性醇已引起人们极大关注.近10年来,用手性金属配合物为催化剂,利用种种有机物作氢源,实现芳香酮的不对称氢转移氢化取得了很大进展.但这些反应过程的催化活性仍然较低,底物酮与催化剂. 相似文献
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高分子在溶液中的单链构象和聚集态结构是高分子科学的重要内容,在研究中往往应用到许多指数经验规律. 总结了几种通常用来研究高分子溶液的指数律方法,并介绍了指数律如何应用于复杂高分子单链及聚集态结构的形状特点研究. 通过前体溶液的调控实现对薄膜凝聚态结构以及形貌的操纵是一种新思路、新方法. 因此,深刻认识高分子在前体溶液中的本征性质尤为重要. 通过指数律研究,结合电镜、光谱等方法,可深入研究高分子溶液单链、聚集尺寸及形态结构演变与各层次结构单元的运动过程及规律,为高分子材料的分子设计、功能开发及应用奠定理论基础. 相似文献
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非均相催化剂(钯碳催化剂)一般会将芳香酮彻底还原至亚甲基产物,而不易得到苄醇类的中间还原产物.本文报道一系列氨基酮用钯碳催化剂催化氢化的结果,随酮底物含有不同种类的氨基而得到不同的氢化产物(亚甲基产物或二级醇产物),部分则不发生还原反应;分析讨论了底物所含氨基对产物的影响及其机理.结果表明,这是一个制备胺基芳香仲醇的有效方法. 相似文献
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Abstract— –Triplet states of several large polycyclic aromatic hydrocarbons together with their lifetimes have been determined both in fluid solution and in the solid state using a spectrophoto-metric technique.
Excited states and lifetimes of some solid charge transfer complexes between the hydrocarbons and chloranil have been examined.
The assignment of the1 B b states of some of the hydrocarbons have been made from the energies of the triplet states. 相似文献
Excited states and lifetimes of some solid charge transfer complexes between the hydrocarbons and chloranil have been examined.
The assignment of the
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THE ''Q-BAND'' ABSORPTION spECTRA OF HEMATOPORPHYRIN MONOMER AND AGGREGATE IN AQUEOUS SOLUTION 总被引:1,自引:0,他引:1
GERALD J. SMITH KENNETH P. GHIGGINO LOUISE E. BENNETT TRACY L. NERO 《Photochemistry and photobiology》1989,49(1):49-52
Abstract The resolution of the absorption spectra in the Q band (480 nm-620 nm) spectral region of monomeric and dimeric hematoporphyrin species present in aqueous solutions has been achieved using absorption, fluorescence and computer analysis methods. The absorption maxima of the dimer in this spectral region are red shifted about 12 nm with respect to those of the monomer. The significance of this finding in relationship to the well documented blue shift of hematoporphyrin aggregate observed in the Soret band region (λmalx ∼400 nm) of the absorption spectrum is discussed. 相似文献
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疏水链段对两亲性三嵌段共聚物在水中聚集行为的影响 总被引:1,自引:1,他引:1
以结构明确的两端为短的聚苯乙烯(PS)或聚甲基丙烯酸甲酯(PMMA)链段,中间为长的聚乙二醇(PEG)链段的PS-b-PEG-b-PS和PMMA-b-PEG-b-PMMA两亲性三嵌段共聚物为对象,研究了PS和PMMA链段对其在水中形成胶束和凝胶的影响.两种三嵌段共聚物在水中形成以PS或PMMA链段为核、PEG链段为壳的球形胶束,流体力学半径Rh,app为15.3~24.3 nm,并随PEG链段长度增长而增大.临界胶束浓度CMC均小于0.01 mg/mL,随着PS和PMMA链段长度的增加而减小.PS-b-PEG-b-PS浓度高于4.5 wt%可形成较强的疏水缔合的物理凝胶,平衡模量Ge可达到103Pa;PMMA-b-PEG-b-PMMA浓度高于7.5 wt%可以形成弱的凝胶,Ge<10 Pa.凝胶的储存模量G′和损耗模量G″均随着PS或PMMA链段的增长而增大. 相似文献
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Abstract— The characteristic near-infrared emission band of O2 (1 Δg ) at 1.28 μ m has been recorded from carbon tetrachloride solutions of the 1, 4-endoperoxides of 1,4-dimethyInaphthalene and 1, 4-dimethoxy-9.10-diphenylanthracene undergoing thermal decomposition. 相似文献
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QUENCHING OF THE TRIPLET STATE OF CHLOROPHYLL a BY ASCORBIC ACID AND ASCORBATE IN ETHANOLIC SOLUTION
Abstract— Ascorbic acid and ascorbate in chlorophyll ethanol solution were found to be fairly efficient quenchers of the chlorophyll triplet state; comparable to the efficiency of ascorbic acid as a quencher in aqueous pyridine solution.
It has been well established that ascorbic acid quenches the triplet state of chlorophyll in aqueous pyridine solution.(1,2) The bimolecular quenching constant, kQ , is very much less than that for O2 or quinine.(3,4)
Information regarding the quenching of the triplet state of chlorophyll by ascorbic acid in ethanolic solution is lacking. There has been some question as to whether ascorbic acid reduces photoexcited chloro-phyll-ethanolic solution because of its high oxidation potential, or because like the ascorbate ion, it acts only as a quencher; both ascorbic acid and ascorbate in high concentrations gave low quantum yields.(5) The quenching of the triplet state by ascorbic acid and ascorbate was determined by the flash-photolytic method. 相似文献
It has been well established that ascorbic acid quenches the triplet state of chlorophyll in aqueous pyridine solution.
Information regarding the quenching of the triplet state of chlorophyll by ascorbic acid in ethanolic solution is lacking. There has been some question as to whether ascorbic acid reduces photoexcited chloro-phyll-ethanolic solution because of its high oxidation potential, or because like the ascorbate ion, it acts only as a quencher; both ascorbic acid and ascorbate in high concentrations gave low quantum yields.
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Abstract —Dilute aqueous hematoporphyrin undergoes a transformation after standing at room temperature leading to a shift of the Soret peak from 395 nm to 405 nm, disappearance of visible bands I (610 nm) and IV (503 nm), a shift of the first emission band from 615 nm to 580 nm, and fluorescence polarization at room temperature. The transformation was accelerated by heating and was faster for more dilute solutions. It did not take place in ethanol, 99:1 glycerol-water, or in small egg lecithin liposomes. It was rapid in SDS micelles and did not occur in CTAB and Triton X-100 micelles. Low concentrations of divalent zinc and copper increased the rate of transformation, but the product was not the corresponding metal ion ligand. The transformation was fast with uroporphyrin I and fast but incomplete with hematoporphyrin derivative. The methyl esters of hematoporphyrin IX and uroporphyrin I did not transform. The tentative identification of the transformed product is a tightly-bound linear micelle, oriented such that the central hydrogens of the free base monomer units are anti-parallel. 相似文献
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Olep I. Kachurin Miss Ljubov I. Velichko Anatolil P. Zarajskii 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2)
Abstract Both the relative reactivities and the initial isomer distributions in the sulphonation of polycyclic hydrocarbons were found to be strongly dependent on the composition of reaction medium. 相似文献
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KLAUS DOSE 《Photochemistry and photobiology》1968,7(6):671-673
Se dan evidencias para explicar los distintos rendimientos cuánticos de fotólisis con lux u.v. para distintos residuos de cisteina en lisozima e insulina. En sistemas modelos de mezclas de aminoácidos, el aminoácido triptofano muestra un marcado aumento en el rendimiento cuántico en la fotólisis de la cisteina. La fotosensibilidad de los residuos de cisteina en la lisozima se interpretan usando la conformación terciaria de la enzima la cual provee una relación espacial entre los residuos de triptofano y cisteina. 相似文献
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Abstract We report direct femtosecond measurements of the excited state dynamics of hematoporphyrin derivative (HpD) in solution. The dynamics are found to be very sensitive to the solvent and pH of aqueous solutions. The decay of the excited singlet states is much faster in acidic and pH 7 buffer aqueous solutions (<230 ps) than in basic aqueous solutions or organic solvents (> 10 ns). The dynamical results show strong correlation with static fluorescence measurements: weaker fluorescence in acidic and pH 7 buffer solutions corresponding to shorter-lived excited states. A new fast decay component with a time constant around 5 ps is identified both in acidic aqueous solutions and in organic solvents such as acetone and attributed to internal conversion from the second to the first excited singlet state of aggregates or certain oligomers in HpD, in accord with the observation that the fast decay component is larger at a higher concentration. Oxygen is found to have no effect on the dynamics on the time scale investigated, 1 ns, indicating that oxygen quenching of the singlet excited states is insignificant on this time scale. The sensitive solvent and pH dependence of the excited state dynamics has important clinical implications in the use of HpD as a photosensitizing agent. 相似文献