苯并异喹啉酮衍生物的合成及其荧光性质

苯并异喹啉酮衍生物的合成及其荧光性质;苯并咪唑苯并异喹啉酮;萘酰亚胺;荧光量子产率;亲核取代反应;合成     

2-异丙基-3-乙氧甲酰基-1,2,3,4-四氢异喹啉-4-酮衍生物的合成

报道了利用3-乙氧甲酰基异喹啉-4-酮分别与胍、脒、脲及硫脲类化合物缩合 反应合成异喹啉并嘧啶衍生物，邻氨基苯甲醛、邻氨基胡椒醛分别与异喹啉-4-酮 反应合成异喹啉并喹啉化合物．6个新化合物的结构通过元素分析、红外光谱、核 磁共振氢谱和质谱予以证实．     

α-吡喃酮衍生物的合成及聚集荧光增强性质研究

设计合成了具有4个苯基取代的α-吡喃酮衍生物,研究了该化合物在溶液中的稳态光物理过程,以及在四氢呋喃/水混合溶剂中的聚集行为和发光性质.该化合物在良溶剂中几乎没有发光,而形成聚集体后发出明亮的蓝绿色荧光,荧光量子产率达17%,比溶液中增强了253倍.根据化合物的结构和低温荧光实验结果推断,聚集荧光增强主要是聚集体中分子...     

苯并咪唑苯并异喹啉酮及其衍生物的电子结构和光谱性质的理论研究

采用密度泛函、含时密度泛函和单激发组态相互作用(CIS)方法研究了苯并咪唑苯并异喹啉酮(1)及其衍生物的电子结构特性和光谱性质,并用极化连续模型考虑了溶剂的影响.结果表明,化合物1及其衍生物的吸收和荧光发射过程的电子垂直跃迁是由于分子内的电荷迁移.化合物1中取代基的位置及给吸电子能力影响其HOMO-LUMO能隙和电荷迁移量.在分子中引入吸电子和给电子取代基,均使最大吸收波长和最大荧光发射波长红移,计算的结果与实验结果吻合得较好.     

镍催化分子氧氧化脱氢偶联反应制备N-芳基四氢异喹啉化合物（英文）

以NiCl_2为催化剂催化N-四氢异喹啉的分子氧氧化脱氢偶联反应,以较高产率制备了一系列N-芳基四氢异喹啉化合物.该方法对不同的N-四氢异喹啉衍生物和亲核试剂均具有较好的适用性,反应均能以较高的产率获得相应的目标产物.与已有方法相比,本方法采用分子氧为氧化剂,具有反应条件温和、底物适用范围广、操作简便等优点,为四氢异喹啉衍生物的制备提供了一种有效途径.     

羿喹啉及其衍生物的电子结构与缓蚀性能关系的研究

本文在30℃, 1.0mol.dm^-3 HCl溶液中用电化学方法测定了异喹啉及其羟基,羧基衍生物对Fe电极的缓蚀效率。并用HMO和CNDO/2方法计算了这些化合物的量子化学参数, 发现异喹啉及其衍生物分子中氮原子电荷和π净电荷越小, 缓蚀性能越好; 随着这些化合物异喹啉环中吡啶环上原子电荷之和的增大, 缓蚀性能提高; 吡啶环亲核前沿电荷与缓蚀效率有很好的线性关系, 提出了这类缓蚀剂分子可能呈平卧方式吸附于金属电极表面, 从而起缓蚀作用, 预测了五个新分子的缓蚀性能。     

羿喹啉及其衍生物的电子结构与缓蚀性能关系的研究

本文在30℃, 1.0mol.dm^-3 HCl溶液中用电化学方法测定了异喹啉及其羟基,羧基衍生物对Fe电极的缓蚀效率。并用HMO和CNDO/2方法计算了这些化合物的量子化学参数, 发现异喹啉及其衍生物分子中氮原子电荷和π净电荷越小, 缓蚀性能越好; 随着这些化合物异喹啉环中吡啶环上原子电荷之和的增大, 缓蚀性能提高; 吡啶环亲核前沿电荷与缓蚀效率有很好的线性关系, 提出了这类缓蚀剂分子可能呈平卧方式吸附于金属电极表面, 从而起缓蚀作用, 预测了五个新分子的缓蚀性能。     

2-乙烯基硝基苯-8-羟基喹啉锌配合物的合成及紫外、荧光性质研究

设计合成了3种8-羟基喹啉衍生物配体:(E)-2-[2-(2-硝基苯基)乙烯基]-8-羟基喹啉(4a),(E)-2-[2-(3-硝基苯基)乙烯基]-8-羟基喹啉(4b),(E)-2-[2-(4-硝基苯基)乙烯基]-8-羟基喹啉(4c)及其相应的锌配合物5a～5c,产物经1H NMR,IR,MS和元素分析技术进行了结构表征.通过紫外滴定模拟了金属锌与配体的配位过程,分别测定了它们固态和溶液状态下的荧光性质:光谱显示化合物5a～5c固体荧光光谱的λmax分别是596,625,592 nm,在DMF溶液中的λmax分别是562,536,618 nm.荧光光谱显示硝基位置的改变可以调控8-羟基喹啉锌配合物的发光性质.     

含三氟苯基8-羟基喹啉锌配合物的合成及紫外、荧光性能对比研究

设计合成了两种含三氟苯基的新型8-羟基喹啉衍生物配体:(E)-2-[2-(2,4,6-三氟苯基)乙烯基]-8-羟基喹啉(B)、(E)-5-[2-(2,4,6-三氟苯基)亚胺基]-8-羟基喹啉(C)及其相应的锌配合物D与E,产物经NMR,IR,MS,元素分析等进行结构表征。通过核磁、紫外滴定跟踪了金属锌与配体的配位过程,并测定了两者溶液状态下的荧光性质:化合物D,E在甲醇溶液中的荧光发射峰位置分别在599 nm和572 nm处;相比于8-羟基喹啉,2位和5位取代8-羟基喹啉衍生物的荧光发生了明显红移。锌配合物固体荧光寿命的测定结果表明,配合物D表现出较长的荧光寿命。     

2-异丙基-1,3-二氢-4(1H)异喹啉酮及其衍生物的合成

报道了异喹啉酮与格氏试剂反应合成四氢-4-羟基异喹啉酮化合物,NBS和混酸(HNO~3/HAc)与异喹啉酮反应合成异喹啉酮衍生物。6个新化合物的结构,通过元素分析,红外光谱和核磁共振氢谱,质谱给予证实。     

NaNO2/FeSO4存在下聚苯乙烯大分子引发剂的合成及嵌段共聚

用NaNO2/FeSO4·7H2O体系替代TEMPO在有机相中合成分子量可控的聚苯乙烯大分子引发剂,引发苯乙烯聚合及酯类单体[如甲基丙烯酸甲酯(MMA)、丙烯酸甲酯(MA)和丙烯酸乙酯(EA)等]聚合,得到两嵌段共聚物.其多分散性指数小于1.5,体现了可控聚合的特征.用大分子引发剂引发苯乙烯进行活性链增长,单体的转化率较高.嵌段共聚物的实测分子量与理论分子量相近,结构经1HNMR和GPC表征.NaNO2/FeSO4·7H2O体系在纯有机相中的应用降低了活性聚合的成本,有利于工业化应用.     

Solvent-controlled photoinduced electron transfer between porphyrin and carbon nanotubes

beta-Cyclodextrin (beta-CD)-modified multiwalled carbon nanotubes (MWCNTs) were successfully prepared by reaction of surface-bound carboxylic chloride groups of MWCNTs with aminoethyleneamino-deoxy-beta-CD (ENCD) and comprehensively characterized by FTIR, Raman, and X-ray photoelectron spectroscopy and thermogravimetric and differential thermal analysis. The beta-CD-modified MWCNTs (ENCD-MWCNTs) are highly water-soluble, with a solubility of ca. 9.0 mg x mL(-1). Furthermore, the photoinduced electron transfer (PET) process between tetrakis(4-carboxyphenyl)porphyrin (TCPP) and ENCD-MWCNTs was investigated by means of fluorescence, fluorescence decay, transient absorption spectroscopy, and cyclic voltammetry. Obvious quenching processes were observed upon addition of both MWCNT-COOH and ENCD-MWCNTs to the aqueous solutions of TCPP, indicating that the PET process between TCPP and carbon nanotubes takes place upon irradiation. When 1-adamantane acetic acid was added to the aqueous solutions of TCPP/MWCNT-COOH and TCPP/ENCD-MWCNTs, respectively, the former fluorescence remains, while the latter fluorescence recovers. On the contrary, the fluorescence intensity of TCPP in the DMF solution was hardly decreased upon addition of ENCD-MWCNTs, whereas its fluorescence was quenched in the presence of MWCNT-COOH. The observations indicate that the CD cavities play a vital role on the control of the PET process.     

The peculiarities of the spectral luminescence properties of N-anthryl-substituted pyridinium cations

A structureless fluorescence band λ^max_f ≈ 530 nm) in liquid solution and a fluorescence band with vibrational structure (λ = 376–480 nm) in rigid media (ethanol, 77 K and poly(methyl methacrylate) (PMMA), 296 K) were observed for N-anthryl-substituted pyridinium cations. In liquid solution the long-wave fluorescence is attributed to the biradical structure resulting from the photoinduced electron transfer (PET) from anthracene to the pyridinium ring, and the long-wave, low intensity absorption (and fluorescence excitation) band (λ=465 nm) is attributed to this interfragment PET which is weakly allowed by the torsional vibrations. In rigid media the PET is strongly forbidden (in the strict orthogonal pyridinium-anthracene structure) and radiative deactivation of the anthracene fragment is observed.     

Determination of the electron transfer parameters of a covalently linked porphyrin-quinone with mesogenic substituents - optical spectroscopic studies in solution

The photoinduced electron transfer (PET) of a covalently linked porphyrin-quinone with mesogenic substituents was studied using visible and near-IR (NIR) spectroscopy. Mesogenic substituents were introduced at the porphyrin moiety in order to mimic the anisotropic membrane properties of the native reaction centre of photosynthesis. Photophysical characterization of this system in homogeneous solution is a prerequisite for a better understanding of the effects occurring in anisotropic medium. For this reason, we studied the fluorescence and phosphorescence quenching and lifetime of the charge-separated state. Time-resolved fluorescence measurements indicated an effective singlet PET. The complete set of PET parameters was calculated using Marcus theory of non-adiabatic electron transfer (ET). Steady state measurement of singlet oxygen luminescence, which allows indirect access to phosphorescence quenching, indicated that no triplet PET was involved in the decay processes. Using transient absorption spectroscopy, the lifetime of the charge-separated state was found to be 1.9 ns.     

用于监控过氧化氮的近红外荧光探针的光物理性质及PET机理

含有机硒的七甲川菁染料是基于光诱导电子转移(PET)的近红外(IR)荧光探针, 能在生理条件下高灵敏、高选择性地监控过氧化氮. 本文应用含时密度泛函理论(TD-DFT)计算方法研究其光物理性质和PET机理.结果表明, 在激发态, 荧光母体发生最高占有分子轨道(HOMO)到最低非占有分子轨道(LUMO)的电子跃迁, 识别基团上的HOMO轨道能级提高到荧光母体的单电子占据的HOMO轨道能级之上, 并向其转移一个电子, 使激发态电子回落过程受阻而导致荧光部分淬灭. 硒被氧化后, 识别基团上的HOMO轨道能级降低, PET过程被阻断, 荧光发射恢复. 研究进一步证明, PET效应来自于识别基团上苯胺N原子的p电子, 它的电子转移能力受到其对位苯硒基的氧化-还原状态的影响, 产生了荧光信号的“开-关”作用.     

多足开链化合物的分子内光诱导电子转移及pH对其荧光的影响

本文合成了含有1～3个萘基取代的脲类柔性开链化合物.通过对该类化合物在溶液中的光物理行为以及受溶液酸度影响的比较研究,发现多足化合物的发光性质强烈地依赖于化合物本身存在的构象形式;同时观察到以叔胺为骨架的三足化合物存在分子内光诱导电子转移反应(PET),且这一过程强烈地依赖于介质的pH值;而叔胺基的氮原子质子化将会减弱这一PET过程.     

Polarized fluorescence spectra of poly(ethylene terephthalate) films

The polarized excitation and fluorescence spectra of lowcrystalline, isotropic poly(ethylene terephthalate) (PET) film samples were measured in the glassy state at room temperature. Whereas the emission anisotropy r₀ of the excitation spectrum, recorded at the fluorescence maximum, changes sharply from 0.35 to 0 with decreasing wavelength in the region around 317 nm, the polarization of the fluorescence spectrum of PET is independent of wavelength. The fluorescence polarization of PET remains constant, if the temperature is increased up to 22 °C above T_g until the light scattering due to the crystallization causes complete depolarization. The photophysical behaviour supports the existence of a dilute solution of groundstate - stable sandwich dimers in the non-crystalline regions of PET.     

The effect of metal catalyst on the discoloration of poly(ethylene terephthalate) in thermo-oxidative degradation

Titanium-based catalyst and ethylene glycol antimony were used as catalysts to prepare poly(ethylene terephthalate) (PET), and the effect of the catalysts on the discoloration of PET in thermo-oxidative degradation was studied by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy. Hydroxylation was found during thermo-oxidative degradation of both the titanium- and antinomy-containing PETs. However, more hydroxylated products were further changed into quinonoid species in the presence of titanium catalyst, which directly results in obviously enhanced coloration of the PET. It indicates that the PET synthesized with titanium-based catalysts is more susceptible to formation of quinonoid groups and discoloration than the PET prepared with ethylene glycol antimony.     

Control of Intermolecular Photoinduced Electron Transfer in Deoxyadenosine-Based Fluorescent Probes

In this work, we report on the Photoinduced Electron Transfer (PET) reaction between a donor (adenine analogue) and an acceptor (3-methoxychromone dye, 3MC ) in the context of designing efficient fluorescent probes as DNA sensors. Firstly, Gibbs energy was investigated in disconnected donor–acceptor systems by Rehm-Weller equation. The oxidation potential of the adenine derivative was responsible for exergonicity of the PET reaction in separated combinations. Then, the PET reaction in donor-π-acceptor conjugates was investigated using steady-state fluorescence spectroscopy, acid-mediated PET inhibition and transient absorption techniques. In conjugated systems, PET is a favorable pathway of fluorescent quenching when an electron-rich adenine analogue ( d7A ) was connected to the fluorophore ( 3MC ). We found that formation of ground-state complexes even at nm concentration range dominated the dye photophysics and generated poorly emissive species likely through intermolecular PET from d7A to 3MC . On the other hand, solution acidification disrupts complexation and turns on the dye emission. Bridging an electron-poor adenine analogue with high oxidation potential ( 8 d7A ) to 3MC presenting low reduction potential is another alternative to prevent complex formation and produce highly emissive monomer conjugates.     

A highly selective and sensitive fluorescence "turn-on" probe for Ag+ in aqueous solution and live cells

A naphthalimide-based fluorescent probe, NPQ, that contains a novel receptor was successfully developed. NPQ exhibited "turn-on" fluorescence and excellent selectivity toward Ag(+) in the presence of various other metal ions in aqueous solution. A series of control compounds were designed and synthesized in order to explore the photoinduced electron transfer (PET) quenching mechanism of NPQ and binding mode of NPQ with Ag(+). Moreover, with the NPQ-Ag(+) complex, I(-) was easily selectively recognized by a marked fluorescence quenching. The live cell imaging experiments demonstrate that NPQ can be used as a fluorescent probe for monitoring Ag(+) in living cells.