偶氮连苯三酚试剂的合成及其光谱特性

合成了 2 -羧基苯胺重氮盐和 2 -羟基苯胺重氮盐 ,它们与连苯三酚偶联 ,得到新的偶氮试剂 4 - (2 -羧基苯偶氮 ) -连苯三酚和 4 - (2 -羟基苯偶氮 ) -连苯三酚。研究了偶氮试剂的红外光谱、紫外光谱和荧光光谱特性。     

Cu2+/TiO2对甲基橙的光催化降解机理

以自制的掺铜离子的混晶型二氧化钛为光催化剂,考察了甲基橙光催化降解过程中pH值和光源的影响,提出了两种不同的光催化降解机理:在高压汞灯照射下,TiO2的价带电子被激发到导带,光生电子和空穴主要通过Cu2+ 的短路循环而复合,光催化剂的活性降低;在太阳光照射下,甲基橙发生自身光敏化氧化反应,受激电子从单线态或三线态的甲基橙分子跃迁到TiO2的导带,Cu2+起到电荷传递中继站的作用,加速了注入电子向H2O2的转移,从而促进了甲基橙的光催化降解。     

Z-scan determination of the third-order optical nonlinearities of an azo dye using diode-pumped Nd:Yag laser

Optical nonlinearity of dye solutions are studied with considerable interest for their wide spread applications ranging from gain media in lasers to all-optical processing signal devices. The third-order nonlinear optical properties of Brilliant Crocein dye was measured by the Z-scan technique and measurements were carried out for different concentrations. The negative sign of the nonlinear refractive index n₂ indicates that this material exhibits self-defocusing optical nonlinearity and purely saturation absorption at the wavelength 532 nm of the diode-pumped Nd:YAG. These results show that Brilliant Crocein has potential applications in nonlinear optics.     

Light-Responsive Polyblend Films with Reconfigurable Surface Micropatterns as Rewritable Information Storage Media

Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering. Herein, a cost-effective yet practical strategy is proposed to fabricate photo-sensitive patterning surface on film/substrate wrinkle system based on an azo-containing polyblend. By manipulating the stress field of the bilayer system globally and/or locally upon the stress relaxation triggered by the reversible cis-trans isomerization of the azobenzene, heating/cooling triggered surface wrinkles on the polyblend films could be tailor-made with visible-light-irradiation. Notably, upon selective photo-irradiation, bespoke surface patterns may be cyclically generated or eliminated, allowing these reconfigurable patterned polyblend surfaces to be used as rewritable information storage media for non-ink printing. The as-prepared photo-printed information patterns with high-resolution are shown to be rewritable for multiple cycles and legible for over 90 d in dark ambient conditions. This study not only provides a versatile strategy for flourishing the stimulus-sensitive systems, but also sheds light on the stress relaxation-triggered morphological evolution of the wrinkling polyblend films.      

Bispalladium(II) Complexes of di-p-Pyrirubyrin Derivatives as Promising Near-Infrared Photoacoustic Dyes

The insertion of palladium(II) into di-p-pyrirubyrin results in mutually convertible bimetallic complexes. Post-synthetic functionalization of one of them yielded bispalladium(II) dioxo-di-p-pyrirubyrin and, after demetallation, dioxo-di-p-pyrirubyrin, introducing for the first time the α,β′-pyridin-2-one unit into the macrocyclic frame. Bispalladium(II) di-p-pyrirubyrin 6 , bispalladium(II) dioxo-di-p-pyrirubyrin 9 , and dioxo-di-p-pyrirubyrin 10 absorb and emit light around 1000 nm and are characterized by high photostability. Thus, they are promising candidates for near-infrared photoacoustic dyes, ideally targeting ( 9 ) the wavelength of Yb-based fiber lasers. The incorporation of an α,β′-pyridine moiety into expanded porphyrins opens a highly interesting area of research due to the attractive optical and coordination properties of the resulting molecules.     

In-situ Monitoring of Photocontrollable Wrinkle Erasure in Azobenzene-based Supramolecular Systems

In this contribution, dynamic photoinduced wrinkle erasure enabled by photomechanical changes in supramolecular polymer-azo complexes was characterized via confocal microscopy. Different photoactive molecules, disperse yellow 7 (DY7) and 4,4′-dihydroxyazobenzene (DHAB), were compared to 4-hydroxy-4′-dimethylaminoazobenzene (OH-azo-DMA). The characteristic erasure times of wrinkles were quickly assessed by using an image processing algorithm. The results confirm that the photoinduced movement on the topmost layer can be successfully transferred to the substrate. Furthermore, the chosen supramolecular strategy allows decoupling the effect of molecular weight of the polymer and photochemistry of the chromophore, allowing quantitative comparison of wrinkling erasure efficiency of different materials and providing a facile way to optimize the system for specific applications.     

Simple sonochemical synthesis,characterization of TmVO4 nanostructure in the presence of Schiff-base ligands and investigation of its potential in the removal of toxic dyes

Thulium vanadate (TmVO4) nanorods were successfully prepared by a simple sonochemical approach using Schiff-base ligands. Additionally, TmVO₄ nanorods were employed as a photocatalyst. The most optimal crystal structure and morphology of TmVO4 have been determined and optimized by varying Schiff-base ligands, the molar ratio of H2Salen, the sonication time and power, and the calcination time. A Eriochrome Black T (EBT) analysis revealed that the specific surface area was 24.91 m2/g. A bandgap of 2.3 eV was determined by diffuse reflectance spectroscopy (DRS) spectroscopy, which makes this compound suitable for visible photocatalytic applications. In order to assess the photocatalytic performance under visible light, two anionic dyes (EBT) and cationic dyes (Methyl Violet (MV)) were used as models. A variety of factors have been studied in order to improve the efficiency of the photocatalytic reaction, including dye type, pH, dye concentration, and catalyst loading. Under visible light, the highest efficiency was achieved (97.7%) when 45 mg TmVO4 nanocatalysts were present in 10 ppm Eriochorome Black T at pH = 10.     

Thiazolylazopyrazoles as Nonsymmetric Bis-Heteroaryl Azo Switches: High-Yield Visible-Light Photoisomerization and Increased Z-Isomer Stability by o-Carbonylation

Following the progress on mono-heteroaryl azo switches (Het-N=N-Ph), a few bis-heteroaryl azo switches (Het-N=N-Het) have been studied recently, whereas the nonsymmetric bis-heteroaryl ones (Het₁-N=N-Het₂) that can combine the respective merits of each heterocycle, have received little attention. Here we report thiazolylazopyrazoles as nonsymmetric bis-heteroaryl azo switches that combine the visible-light switching character of the thiazole ring and the ease of o-substitution of the pyrazole ring. Thiazolylazopyrazoles can achieve (near-)quantitative visible-light isomerization in both directions and long Z-isomer thermal half-lives of several days. In contrast to the drastically destabilizing effect of o-methylation, o-carbonylation of the pyrazole ring can remarkably stabilize Z isomers by inducing attractive intramolecular interactions (dispersion, C−H⋅⋅⋅N bond, and lone-pair⋅⋅⋅π interaction). Our work highlights the importance of the rational combination of two heterocycles and suitable structural substitution in developing bis-heteroaryl azo switches.