香豆素衍生物与碘Weng盐间的光诱导电子转移研究

研究了３种碘Ｗｅｎｇ盐对３种香豆素荧光的猝灭,发现猝灭曲线符合Ｓｔｅｍ Ｖｏｌｍｅｒ方程并且猝灭过程受扩散控制。研究证实了猝灭的机理是由于发生了光诱导电子转移。通过香豆素衍生物－碘Ｗｅｎｇ盐体系能在光照下引发甲基丙烯酸甲酯单体的聚合进一步证实了这种机理。尽管香豆素有较强的分子内电荷转移倾向,但由于碘Ｗｅｎｇ盐阳离子很强的拉电子能力,它们间还是能发生快速的电子转移。     

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(PQ~(2+))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。     

香豆素染料与羟基苯基碘鎓盐光敏引发体系的研究

本文通过吸收光谱、荧光猝灭、光聚合方法对羟基苯基碘盐(HTIB)的光敏引发体系进行了研究,发现具有给电子性的光敏剂香豆素1可以将引发剂羟基苯基碘盐的光响应移到长波区,而引发聚合效率与溶剂的性质有很大的关系.在一般极性溶剂中如DMSO中能有效地引发甲基丙烯酸甲酯(MMA)光聚合,而在电子受体性质的极性溶剂如乙腈中,光聚合反应受阻,这归结于香豆素1与羟基苯基碘盐形成络合物,使得光反应后生成不具活性的产物.该结果对研究其它单苯基碘盐的光敏体系提供了有价值的信息.     

以聚醚链相连的9-氨基吖啶、苯甲酸酯二元体系的合成及分子内光诱导电子转移反应

本文用聚四乙二醇柔性链将９－氨基啶和不同取代基的苯甲酸酯连接起来，合成了一类新型二元分子体系。对各体系中９－氨基啶的电子转移荧光猝灭进行了研究，并根据稳态荧光猝灭计算了体系中的荧光猝灭效率和荧光猝灭速率常数。     

香豆素染料与羟基苯基碘锚盐光敏引发体系的研究

本文通过吸收光谱、荧光猝灭、光聚合方法对羟基苯基碘镛盐（HTIB）的光敏引发体系进行了研究，发现具有给电子性的光敏剂香豆素1可以将引发剂羟基苯基碘镛盐的光响应移到长波区，而引发聚合效率与溶剂的性质有很大的关系．在一般极性溶剂中如DMSO中能有效地引发甲基丙烯酸甲酯（MMA）光聚合，而在电子受体性质的极性溶剂如乙腈中，光聚合反应受阻，这归结于香豆素1与羟基苯基碘镛盐形成络合物，使得光反应后生成不具活性的产物．该结果对研究其它单苯基碘镛盐的光敏体系提供了有价值的信息．     

N—丁基—2—乙氧基硫代吖啶酮的光化学反应机理

采用荧光光谱研究了N－丁基－2－乙氧基硫代吖啶酮的光化学反应机理。结果表明：在Xe灯光照下，N－丁基－2－乙氧基硫代吖啶酮转变成了相应的吖啶酮，用紫外－可见光谱和质谱证实了吖啶酮的存在；生成的吖啶酮可被二苯基碘翁盐猝灭，它们之间的荧光猝灭遵循电子转移的反应机理，实验又证明了由硫代吖啶酮、二苯基碘翁盐和硫代水杨酸三者组成的光聚合引发体系的引发效果最好。     

以吖啶染料荧光猝灭为基础的卤素阴离子检测研究

合成了两种吖啶及吖啶橙盐类小分子化合物和带有吖啶盐的三元共聚物，研究了它们在溶液中的荧光被卤素离子猝来的问题，发现它们能强烈地被碘离子所猝灭而不易被氯离子猝灭，表明这类化合物有可能用于在有氯离子存在条件下对碘、溴离子的检测，对荧光猝灭机理进行的研究发现，卤素离子的猝灭能力并不和它们对发光化合物的系间窜越和三重态的生成等有关，而是和阴离子对极化分子的作用减弱了分子内的电荷转移能力相关。     

有机电致发光器件中几种常用组分的荧光光谱研究

利用荧光光谱对电致发光器件(OLED)中几种常用化学组分的荧光猝灭和光诱导电子转移问题进行了研究．发现两种常用的空穴传输材料NPB和TPD与常用电子传输材料AlQ3在光的帮助下可发生电子转移、根据荧光猝灭的Stern—Volmer作图和用单光子记数法测得的荧光寿命而计算得到的猝灭速度常数和扩散速度常数相对应，明确地表明这里的猝灭具有电子转移特征、并对所得的结果进行了讨论。     

2－芳基苯并噁唑的荧光猝灭和光诱导电子转移研究

本工作对两种不同的２－芳基苯并　唑化合物溶液荧光被四氯化碳所猝灭的机理进行了详细研究，通过多种途径研究表明该猝灭过程具有光诱导电子转移性质，工作还利用此电子转移所形成的活泼自由基来引发烯类单体的聚合，得到了有一定聚合度的聚甲基丙烯酸甲酯。     

2—芳基苯并恶唑的荧光猝灭和光诱导电子转移研究

本工作对两种不同的２－芳基苯并恶唑化合物溶液荧光被四氯化碳所猝灭的机理进行了详细研究，通过多种途径研究表明该猝灭过程具有光诱导电子转移性质。工作还利用此电子转移所形成的活泼自由基来引发烯类单体的聚合，得到了有一定聚合度的聚甲基丙烯酸甲酯。     

Efficient visible photoinitiator with high‐spectrum stability in an acid medium for free‐radical and free‐radical‐promoted cationic photopolymerization based on erythrosine B derivatives

Three dye‐linked photoinitiators with excellent spectral stability in an acid medium were synthesized by the covalent bonding of a coinitiator (tertiary amine) and a benzoyl group or two coinitiators to the phenolic and carboxyl group position of erythrosine B. The combination of the iodonium salt and free tertiary amino used to initiate the free‐radical/cationic visible photopolymerization was investigated to acquire the relationship between the structure and performance. The photoinitiating ability of the derivative with the phenolic position bearing a coinitiator was poorer than of the derivative with the carboxyl group bearing one because of the strong back electron transfer of the former. For the derivative with a linked coinitiator on the carboxyl position, the proximity effect between the sensitizer and the coinitiator moiety resulted in an excellent photoinitiating ability for radical/cationic polymerization; this suggested its potential for application. Although radical/cationic photopolymerization could be initiated by the derivative/coinitiator/iodonium salt, the different component ratios between them had different effects on these two polymerizations; this provided useful information for the design of effective photoinitiators for different polymerizations. On the basis of the fluorescence quenching and photopolymerization results, a corresponding synergistic mechanism was proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43035.     

Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

3,6-Dimethyl-9-phenyl-1,3,4,5,6,8,9,10-octahydropy-rano-[4,3-b:4′,3′-e]-pyyridine-1,8-dione ( 3 ) was prepared as first derivative of a novel substance class exhibiting a 1,4-dihydropyridine structural element. Diazonium, iodonium, sulfonium and phosphonium salts act as electron acceptors both for ground state charge transfer complex formation and in single electron transfer processes (SET) with excited states of compound 3. Solvents strongly influence the rate constants of fluorescence quenching. Those containing a hydroxyl group decrease these rate constants as well as the quantum yields of SET due to higher solvent reorganization energies. Some expressions have been developed to describe the strong solvent effect. Due to a less effective population of the triplet state, the quantum yields of the SET's are low.     

方酸菁染料/二芳基碘鑑盐体系引发丙烯酸酯光交联反应

近年来随着高新技术的迅猛发展,激光技术和光化学也随之大量应用到先进材料中,为适应这种发展需要,开发感可见光和近红外光的光敏反应体系已成为十分迫切的研究课题［１,２］．方酸类染料是一类重要的功能性染料,广泛地应用于静电复印、太阳能电池和光记录材料［３］...     

碘鎓盐/胺光引发聚合体系的初级反应研究

碘鎓盐/胺复合体系,用作自由基光敏聚合的引发剂具有良好的效果,但是关于碘鎓盐和胺相互作用产生有引发活性的自由基的光化学反应机制尚不清楚。Ptitsyna曾研究了二苯基碘鎓盐和三苯基膦的光化学反应,认为首先发生鎓盐的裂解反应,接着进行芳基化作用,生成主要产物四苯基鏻和碘苯。而二芳基碘鎓盐和脂肪胺的热化学反应,则得到的主要胺类产物为原始胺的盐,芳基化产物很少。 本工作以二苯基碘鎓盐(DPIOC)/三乙胺(TEA)为例子,研究了这类化合物的光化学反应。采用高压汞灯为光源,并滤去<300nm的光,介质为CH_3CN/H_2O(14:1,V/V)混合溶剂,反应在N_2下进行,温度为30℃。关于碘鎓盐和叔胺分子间的相互作用,从     

分子内敏化鎓盐的合成及光敏性研究

二芳基碘鎓盐和三芳基硫鎓盐是阳离子聚合的光引发剂和光敏产酸物,但他们在300nm以上的光吸收很低,限制了对紫外光的利用效率。为解决此问题,本文合成了一些新的碘鎓盐和硫鎓盐,并用凝胶时间方法考察了它们的光引发效率。实验结果表明,2-苯硫基甲基,2′,4′-二甲基二苯碘鎓盐和9-蒽丙基,二苯基硫鎓盐具有特别高的光引发效率,这归之于光照时这些鎓盐发生了分子内电荷转移反应,即发生了分子内敏化。9-蒽丙基二苯硫鎓盐分子中的蒽基(An)是电子给体也是敏化基团,光照时可发生如下反应:     

Photoinduced electron transfer in nanostructures of ultrathin polyimide films containing porphyrin moieties

Photoinduced electron transfer between porphyrin moieties and pyromellitimide fragments has been investigated in multi-layered structures of ultrathin polyimide films prepared by the Langmuir-Blodgett (LB) technique. The LB films were composed of three kinds of polyimides, which contained zinc tetraphenylporphyrin (ZnTPP) unit as an electron donor (D-layer), no chromophoric groups (S-layer), and pyromellitimide fragments as an electron acceptor (A-layer). The layered structure and orientational distribution of porphyrin moieties in the LB films were evaluated by surface plasmon measurement and absorption dichroism measurement, respectively. The thickness of monolayer was estimated to be 0.9 nm for the polyamic acid films and 0.4 nm for the polyimide films. The molecular plane of porphyrin moieties was oriented in the direction parallel to the substrate plane. In the multi-layered structures of polyimide LB films, the efficiencies of photoinduced electron transfer from porphyrin moieties to pyromellitimide fragments varied sharply with the number of spacing layers, indicating that the short-range interactions such as electron transfer could be controlled by the fabric of ultrathin films. The rate of electron transfer observed by the fluorescence quenching measurements was numerically simulated for the nanostructure using the Monte Carlo method.     

Homolytic reduction of onium salts

Onium salts have proved to be efficient sources of carbon-centered radicals. They can undergo homolytic reduction by single electron transfer (SET) and participate in subsequent synthetic transformations. This review aims to provide an overview on the behavior of onium salts including diazonium, sulfonium, selenonium, telluronium, phosphonium and iodonium cations toward various reductive methods such as radiolysis, electrolysis, photolysis or the use of SET reagents. Mechanistic and synthetic aspects are presented. Applications in polymers and materials science are not covered.     

Sunlight photodepolymerization of transient polymers

The study and development of transient devices is an emerging field where the disposal of a device after use is desired to avoid reverse engineering and minimize the environmental impact. Polyaldehydes with phototriggers have been investigated because the radiation wavelength can be adjusted to meet the transient application. Polynuclear aromatic hydrocarbons (PAHs) were used as the optical sensitizer for photoacid generators (PAGs). Photoinduced electron transfer (PET) with an iodonium-based PAG was used to expand the spectral sensitivity range. Anthracene, tetracene, and pentacene derivatives were synthesized with appended phenylethynyl groups to improve the solubility of the sensitizer and adjust the absorption wavelength. Sensitization of the iodonium-based PAG with the PAH derivatives was found to have thermodynamically favorable PET reactions for depolymerization of poly(propylene carbonate) and poly(phthalaldehyde) (PPHA). The Rehm–Weller equation and Stern–Volmer analysis were used to study the electron transfer and the fluorescence quenching rates of the PAHs with the iodonium salts, respectively. The photosensitivity, efficiency, and byproducts of the PET reactions in the decomposable polymer films are reported. A rapid photoreaction is reported for the depolymerization of PPHA exposed to a sunlight dose of <6 J cm⁻² (i.e., 1 min of direct sunlight) with a pentacene-based sensitizer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47141.