吲哚-9,10-二甲氧基蒽体系分子内能量转移反应的研究

本文分别用亚甲基和甾体雌二醇刚性链将吲哚与9,10-二甲氧基蒽连接起来,合成了两个分子内能量转移体系,研究了分子內吲哚的激发能向9,10-二甲氧基蒽的传递过程与距离及溶剂环境的关系;发现在两个体系中激发吲哚都可以发生从吲哚到9,10-二甲氧基蒽的单重态-单重态能量转移,在远距离的条件下,能量转移按偶极子-偶极子共振机制进行,由实验结果,根据Forster公式计算得到的给体与受体之间的距离与用分子模型测量得到的距离是一样的,并研究了溶剂极性对能量转移过程的影响。     

新的酰胺型开链冠醚的合成与性质

Simon在70年代开发了一类酰胺型开链冠醚,能选择性配位碱土金属离子并可作为中性载体制备离子选择性电极.由于酰胺型开链冠醚易于制备,因此受到人们广泛地重视.Vgtle等提出的“末端基”概念为开链冠醚的合成、设计起了重要的指导作用.前文报道2-甲氧基-1-氨甲基萘与三甘醇二碘化物在无水碳酸钠存在下于乙腈中反应得到双手臂的套索冠醚与碘化钠的配合物.X射线衍射晶体结构分析表明萘环上的甲氧基中的氧原子参加了与钠离子的配位,生成了扭曲的六边形双锥结构配合物.因此2-甲氧基-1-氨基萘可以作为开链冠醚的“末端基”.开链冠醚的合成路线是:     

新型蒽并冠醚的合成及主客体键合行为

以9,10-二溴甲基蒽为原料,经过3步反应合成了2种新型蒽并冠醚;采用核磁共振波谱、紫外光谱和单晶X射线衍射等手段研究了蒽并冠醚与2种π-缺电子客体之间的键合行为.结果表明,蒽并冠醚与客体之间的键合作用主要是π-堆积作用.通过紫外光谱滴定法测得蒽并冠醚与客体之间的键合常数高于经典的苯并冠醚和萘并冠醚,表明蒽结构基团的引入改善了冠醚的主-客体键合能力.     

开链冠醚类似物的合成与研究Ⅰ.

由于开链冠醚类似物具有某些与冠醚类似的性能,且合成操作简便,成本较低,配位作用迅速,引起了人们的研究兴趣。Vogtle等在研究末端带取代基的短链开链冠醚类似物基础上,提出了“末端基概念”,指出末端基的结构对这类化合物的性能有很大影响。现已见报道的末端基尚不多。作者以4-氧安替比林及4-氧硫代安替比林作为新的末端基,合成了开链冠醚类似物1-8     

电化学方法用于分子内电荷转移特性的研究

设计合成一系列具有不同取代基的苯甲酰萘（苯）胺衍生和，测定它们在非极性溶剂环己烷中的荧光发射光谱，发现系列合成产物具有双重荧光，其长滤发射具有电荷转移特性，其长波发射态能量与不同取代基的苯甲酰萘（苯）胺衍生物的失（得）电子能力，即给（受）体的氧化还原电位之间符合Weller方程。     

芴酮对聚醚侧链聚芴体系的影响: 合成, 表征及光物理性质的研究

利用Yamamoto聚合反应, 通过调节单体2,7-二溴9,9'-二-(三乙氧基甲基)芴和2,7-二溴芴酮的比例, 合成了侧链为极性聚醚链, 芴酮含量逐渐增加的聚芴系列. 通过聚合物溶液及固态薄膜的紫外荧光谱图, 深入研究芴酮作为能量受体的能量转移过程及其对聚合物光物理性质的影响. 结果表明: 稀溶液中体系呈现聚芴本征态的荧光发射, 能量转移对溶液浓度具有依赖性; 固态薄膜中能量转移效率随芴酮含量的增加而快速增长, 退火后这种现象更加明显.     

高分子三线态敏化剂分子中能量迁移的研究 Ⅰ.聚(乙烯基二苯酮-β-乙烯基萘)中的能量迁移的研究

本工作对乙烯基二苯酮-β-乙烯基萘共聚物体系分子内的能量迁移和转移进行了研究.在77K玻璃态溶液中,不论以310nm或以370nm波长激发时,共聚物都发生强的萘燐光.各共聚物三线态能量转移量子效率φ_(ET)~(T-T)大于80％,表明此高分子体系能有效地进行三线态能量迁移和转移.     

高分子三线态敏化剂分子中能量迁移的研究 I. 聚(乙烯基二苯酮-β-乙烯基萘)中的能量迁移的研究

本工作对乙烯基二苯酮-β-乙烯基萘共聚物体系分子内的能量迁移和转移进行了研究,在77K玻璃态溶液中,不论以310nm或以370nm波长激发时,共聚物都发生强的萘光,各共聚物三线态能量转移量子效率φET^T^-^T大于80%,表明此高分子体系能有效地进行三线态能量迁移和转移。     

不同位置取代的三氰基乙烯基蒽的光谱行为的研究

本文设计合成了两个典型的共轭的电子给体与电子受体(D-A)化合物:2-三氰基乙烯基蒽(2-TCVA)与9-三氰基乙烯基蒽(9-TCVA),通过极性效应,温度效应对它们基态与激发态的光谱行为进行了表征。研究表明:这两个化合物均表现出显著的电荷转移(CT)吸收峰,分子受光激发后,9-TCVA只能在非极性溶剂中产生分子内电荷转移(ICT)态荧光,而2-TCVA在极性与非极性溶剂中都能从ICT态发光。另外,温度效应显示冻结态下,2-TCVA只发射ICT态荧光,而9-TCVA既发射类蒽(anthracene-like)荧光又发射ICT态荧光,造成这一现象的主要原因可能是2-TCVA与9-TCVA分子平面性上的差异而引起分子内电荷转移相互作用不同所致。文中还利用了Bilot-Kawski公式估算了化合物2-TCVA在激发态与基态时偶极矩的差值为18.8D。     

羧脒盐桥介导的单重态能量传递直接观察

设计构建了以羧脒盐桥联接的萘和蒽超分子组装体系,NA-(脒基-羧基)-An以及相应的模型体系.稳态和时间分辨荧光光谱研究表明,置于羧脒盐桥两端的萘和蒽基团之间发生了从萘到蒽的单重态能量传递,NA-(脒-羧)-An超分子体系中单重态能量传递效率和速率常数分别大于0.99和9.9×10⁹s^-1.推测羧脒盐桥介导了体系中的单重态能量传递过程,单重态能量传递‘通过键’以电子交换机制进行.     

含有双发色团的化合物分子内能量传递的研究

合成了一系列含有萘环和蒽环的不同链长的二元化合物, 简写为N-Mn-A(n=2,4,6,8,10)。在有机溶剂中做了上述系列化合物的荧光光谱。激发波长为λex=280nm时, 发现荧光光谱中有两个发射峰, λem1=370nm, λem2=450nm。前者为萘的荧光峰, 后者为蒽的荧光峰。实验证明, 只有萘吸收280nm的光, 而蒽无吸收。所以在激发萘的条件下, 能量由处于激发态的萘环传向了外于基态的蒽环。在不同的有机溶剂中, 分别做了该系列化合物的荧光光谱随浓度的变化。实验结果指出, 两个荧光峰强度的比值不随浓度的变化而变化, 表明其能量传递为分子内的能量传递。另外在1%的糖淀粉水溶液中, N-Mn-A的浓度为1.0×10^-^5mol.dm^-^3,通过荧光光谱发现没有发生能量传递。表明处于伸展状态的N-Mn-A化合物分子不能发生能量传递。     

STUDIES OF THE ANTENNA EFFECT IN POLYMER MOLECULES ENERGY MIGRATION AND TRAPPING IN NAPHTHALENE-CONTAINING POLYELECTROLYTES*

Polymers of 1- and 2-vinylnaphthalene containing more than about 50mol% sulfonic acid groups dissolve in water to form "hypercoiled" conformations whichhave many of the properties of micelles. Hydrophobic molecules such as anthracene andperylene are selectively absorbed in these pseudo micellar structures, and their fluorescenceemission is sensitized by energy transfer from the surrounding naphthalene chromophores.When irradiated with UV light in the presence of oxygen, the emission of perylene rapidlydecreases. It is proposed that this is due to reaction of singlet oxygen with the perylenetrapped in the hypercoiled polymer.     

Theoretical investigation of hole mobility in 9,10-diphenylanthracene by density functional calculations

The charge transfer property of the 9,10-diphenylanthracene (DPA) single-crystal system was investigated by density functional calculations. The hole mobility of DPA was predicted according to a hopping mechanism and compared with that of two standard organic single-crystal systems, namely, naphthalene and anthracene. The reorganization energy was calculated by the adiabatic potential energy surface method. The electronic coupling matrix elements were calculated by two methods, namely, the energy splitting in dimer (ESD) method and charge transfer integral (CTI) method. Using the coupling matrix calculated by the CTI method, we predicted a hole mobility of 2.15?cm²/(Vs) for DPA, whereas the CTI method gives the values of 0.35 and 1.39?cm²/(Vs) for naphthalene and anthracene, respectively. It is shown that the electronic coupling calculated by the CTI method gives the qualitatively satisfactory result for the hole mobilities of the three single-crystal systems.     

Novel chemosensor for alkaline earth metal ion based on 9-anthryl aromatic amide using a naphthalene as a TICT control site and intramolecular energy transfer donor

Novel fluorescent chemosensors 1 and 2 with two different fluorophores (naphthalene and anthracene) at the both ends of polyether was synthesized. These compounds based on 9-anthryl aromatic amide adopted a naphthalene as a TICT controller and an intramolecular energy transfer source. Compound 1 shows high fluorescence efficiency upon complexation with metal ion, and the fluorescence efficiency of 2 is regulated by metal ionic size.     

2-脲基-4[1氢]-嘧啶酮四氢键萘-蒽超分子组装体系:"通过键"机制的单重态能量传递

设计合成了基于2-脉基-4[1氢]-嘧啶酮AADD四氢键萘-葱超分子组装体系UPNa·UPAn.稳态和时间分辨荧光光谱研究表明UPNa·UPAn四氢键组装体可以发生从茶到葱的高效、快速的单重态能量传递过程.体系内光诱导单重态能量传递的速度和效率远大于通过F(o)rster机制的单重态能量传递速率,表明组装体系UPNa·...     

Theoretical study on oligoacenes and polycyclic aromatic hydrocarbons using the restricted active space self-consistent field method

This is the first study, to my knowledge, to report the optimized geometries and vibrational frequency analysis for oligoacenes (naphthalene, anthracene, naphtacene, and pentacene) and polycyclic aromatic hydrocarbons (PAHs; perylene, phenanthrene, and picene) by using the restricted active space self-consistent field (RASSCF) method. For naphthalene, both the complete active space self-consistent field (CASSCF) and RASSCF calculations were performed. As a result, it was confirmed that the RASSCF, with its small computational costs, is appropriate for oligoacenes and PAHs. It should be noted that, for anthracene and perylene, the optimized geometries under D(2h) symmetry were not the minimum energy points, whereas the optimized geometries under C(s) symmetry were the minimum energy points. For naphthalene, anthracene, naphtacene, pentacene, and phenanthrene, the calculated bond lengths and infrared absorption spectra by the RASSCF were in good agreement with the experimental values.     

Electronic structure and chemical bond in naphthalene and anthracene

We investigated the electronic structure of crystalline naphthalene and anthracene within the framework of density functional theory including van der Waals interactions (DFT-D). It is established that for better agreement with experimental values it is necessary to use the increased values of the van der Waals radii, which is caused by an overestimated value of the van der Waals interactions in crystalline linear oligoacenes. Utilization of the DFT-D leads to a correct account of the dispersion forces, which results in a high precision of the computed lattice parameters and cohesive energy. Based on the relaxed crystal structures, we have computed the total and deformation electron density and determined the mechanism of chemical bonds formation in crystals of naphthalene and anthracene. It has been established that the chemical bond in molecular crystals is formed under the influence of not only intramolecular but also intermolecular interactions. On the basis of the Mulliken population analysis it was revealed that two C(3) atoms in naphthalene (or C(3) and C(4) in anthracene) have a positive charge and the population of the rest of the carbon atoms increased, as compared with isolated molecule.     

Investigation on photophysical properties of a substituted 3H-indole-modified β-cyclodextrin: II. Efficient photoinduced energy transfer with naphthalene and its derivatives

Photoinduced energy transfer is observed in the supramolecular assemblies of mono-6-deoxy-(2-[(p-amino) phenyl]-3,3-dimethyl-5-carboxyl-3H-indole)-β-CD (compound A) with naphthalene and its derivatives, which are stabilized via hydrophobic interactions in aqueous solutions. According to Förster theory, the critical transfer radius R₀ was calculated. It was found that the energy transfer efficiency from naphthalene and its derivatives to compound A is very high and is increased with increasing their inclusion percents in the β-CD cavity of compound A. Energy transfer efficiencies for 2-methoxynaphthalene and 2-naphthol are not much different, but larger than that of naphthalene at the same molar ratio of donor to acceptor. But, when the molar ratio reaching 1:10, the difference in the energy transfer efficiency for the three donors is negligible.     

Aspects of plastic scintillators. II. Energy transfer studies in polymerizing media

Changes in scintillation efficiency during formation of plastic scintillator compositions have been studied. The separate roles of energy transfer and solute fluorescence efficiencies in the determination of the observed luminescence output of the systems were elucidated. Bis-1,4-2-(5-phenyloxazolyl)benzene(POPOP); 1,1′,4,4′-tetraphenylbutadiene(TPB), and 9-methyl anthracene (MAN) were employed as scintillator solutes. The increased scintillation yield of polymerizing solutions of POPOP is primarily a consequence of increased energy transfer efficiency from solvent to solute. Solutions of TPB exhibit enormous increases in luminescence output upon formation of polymers. The major contributor to the overall effect is the great enhancement of the fluorescence efficiency of TPB which occurs when the microviscosity of the medium is increased. MAN solutions exhibit a decreasing luminescence yield upon polymerization despite increasing energy transfer efficiency. Structural rearrangements of the fluor, consequent upon involvement in the polymerization kinetic chain, are responsible for the decreased scintillation efficiency.