Theo-chlorotoluene photodissociation at 266 nm

Based on theab initio calculation results, the hydrogen atom transfer has been investigated. In order to explain the experimental results, a new mechanism is proposed, that is, hydrogen transfer occurs before but not after CI atom eliminates from aromatic ring. The calculation result strongly supports this mechanism.     

Cl+HD反应产物的极化与态分布

利用准经典轨线理论 ,在BW 2和G3两个势能面上 ,研究了Cl +HD反应的动力学 .计算结果表明 ,产物的转动取向对势能面及反应体系的质量因子非常敏感 .在BW 2势能面上 ,计算的两个产物的转动取向强于在G3势能面上计算的结果 ,而无论是在BW 2势能面上还是在G3势能面上 ,DCl产物的取向都强于HCl产物的取向 .计算结果还表明 ,在不同的势能面上反应物的转动激发对反应的影响有着显著的不同 .在BW 2势能面上 ,反应物的初始转动激发有利于Cl+HD反应的进行 ;而在G3势能面上 ,反应物的初始转动激发消弱了反应的反应性     

环境质量评价热力学方法探讨

对理想气体或理想溶液有:■实际分析中有 X(大气)→1,■考虑评价的任一组分有 E_p=RT■,E_p 取决于 X■的选定和 X_p 环境监测值的大小,以此为基础进行环境质量评价方法探讨.     

Colloidal Synthesis and Charge‐Carrier Dynamics of Cs2AgSb1−yBiyX6 (X: Br,Cl; 0 ≤y ≤1) Double Perovskite Nanocrystals

A series of lead‐free double perovskite nanocrystals (NCs) Cs₂AgSb_1?yBi_yX₆ (X: Br, Cl; 0≤y≤1) is synthesized. In particular, the Cs₂AgSbBr₆ NCs is a new double perovskite material that has not been reported for the bulk form. Mixed Ag–Sb/Bi NCs exhibit enhanced stability in colloidal solution compared to Ag–Bi or Ag–Sb NCs. Femtosecond transient absorption studies indicate the presence of two prominent fast trapping processes in the charge‐carrier relaxation. The two fast trapping processes are dominated by intrinsic self‐trapping (ca. 1–2 ps) arising from giant exciton–phonon coupling and surface‐defect trapping (ca. 50–100 ps). Slow hot‐carrier relaxation is observed at high pump fluence, and the possible mechanisms for the slow hot‐carrier relaxation are also discussed.     

Air‐Stable,Lead‐Free Zero‐Dimensional Mixed Bismuth‐Antimony Perovskite Single Crystals with Ultra‐broadband Emission

Lead‐free zero‐dimensional (0D) organic‐inorganic metal halide perovskites have recently attracted increasing attention for their excellent photoluminescence properties and chemical stability. Here, we report the synthesis and characterization of an air‐stable 0D mixed metal halide perovskite (C₈NH₁₂)₄Bi_0.57Sb_0.43Br₇?H₂O, in which individual [BiBr₆]^3? and [SbBr₆]^3? octahedral units are completely isolated and surrounded by the large organic cation C₈H₁₂N⁺. Upon photoexcitation, the bulk crystals exhibit ultra‐broadband emission ranging from 400 to 850 nm, which originates from both free excitons and self‐trapped excitons. This is the first example of 0D perovskites with broadband emission spanning the entire visible spectrum. In addition, (C₈NH₁₂)₄Bi_0.57Sb_0.43Br₇?H₂O exhibits excellent humidity and light stability. These findings present a new direction towards the design of environmentally‐friendly, high‐performance 0D perovskite light emitters.     

Three‐in‐One Oxygen Vacancies: Whole Visible‐Spectrum Absorption,Efficient Charge Separation,and Surface Site Activation for Robust CO2 Photoreduction

A facile and controllable in situ reduction strategy is used to create surface oxygen vacancies (OVs) on Aurivillius‐phase Sr₂Bi₂Nb₂TiO₁₂ nanosheets, which were prepared by a mineralizer‐assisted soft‐chemical method. Introduction of OVs on the surface of Sr₂Bi₂Nb₂TiO₁₂ extends photoresponse to cover the whole visible region and also tremendously promotes separation of photoinduced charge carriers. Adsorption and activation of CO₂ molecules on the surface of the catalyst are greatly enhanced. In the gas‐solid reaction system without co‐catalysts or sacrificial agents, OVs‐abundant Sr₂Bi₂Nb₂TiO₁₂ nanosheets show outstanding CO₂ photoreduction activity, producing CO with a rate of 17.11 μmol g^?1 h^?1, about 58 times higher than that of the bulk counterpart, surpassing most previously reported state‐of‐the‐art photocatalysts. Our study provides a three‐in‐one integrated solution to advance the performance of photocatalysts for solar‐energy conversion and generation of renewable energy.     

石墨烯材料生物降解的策略研究

自2004年被发现以来,前沿新材料石墨烯及其衍生物由于其独特的电学、光学和力学性能被广泛关注,在许多领域都展露了光彩,包括新型电池、传感器、新能源和生物医学等领域,尤其在生物医药领域发展迅速.石墨烯及其衍生物良好的生物相容性使其在生物领域中具有重要的应用前景.为了实现石墨烯材料的体内应用,材料的可降解性是值得深入研究的焦点,研究其生物降解行为有助于提高其对环境、生命系统的安全性.到目前为止,石墨烯的生物降解研究主要集中在材料的生物酶促降解,利用一系列方法如异质原子掺杂、表面功能化修饰等对石墨烯材料进行改性,可以调控石墨烯材料的降解.综述了近年来石墨烯材料及其衍生物在生物应用上的降解的研究进展,重点介绍石墨烯的酶促降解和其在生物医学领域的应用前景,为进一步促进石墨烯材料的体内研究提供重要的研究基础和指导意义.     

5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚的合成及其对Zn2+的识别

本文利用2-氨基吡啶与4-二乙胺基水杨醛反应合成了5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚(探针L),对其结构进行了表征。在DMSO/Tris(6:4, v/v, pH =7.4)溶液中,探针L高选择性荧光“关-开”识别Zn₂₊,在365 nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L与Zn₂₊的结合比为1:1,结合常数为2.6×10₃ L. mol_-1,检测限为 9.39×10_-7mol/L,pH适用范围为7-11,并可检测水样中的Zn₂₊。     

A New Thiosemicarbazone-Based Fluorescence “Turn-on” Sensor for Zn<Superscript>2+</Superscript> Recognition with a Large Stokes Shift and its Application in Live Cell Imaging

Selective fluorescence turn on Zn²⁺ sensor with long-wavelength emission and a large Stokes shift is highly desirable in Zn²⁺ sensing area. We reported herein the synthesis and Zn²⁺ recognition properties of a new thiosemicarbazone-based fluorescent sensor L. L displays high selectivity and sensitivity toward Zn²⁺ over other metal ions in DMSO-H₂O (1:1, v/v, HEPES 10 mM, pH = 7.4) solution with a long-wavelength emission at 572 nm and a large Stokes shift of 222 nm. Confocal fluorescence microscopy experiments demonstrate that L is cell-permeable and capable of monitoring intracellular Zn²⁺.

Open image in new window

Graphical Abstract We report a new thiosemicarbazone-based fluorescent sensor (L) for selective recognition of Zn²⁺ with a long wavelength emission and a large Stokes shift.