Theoretical study of proton coupled electron transfer reaction in the light state of the AppA BLUF photoreceptor

The BLUF (blue light sensor using flavin adenine dinucleotide) domain is widely studied as a prototype for proton coupled electron transfer (PCET) reactions in biological systems. In this work, the photo-induced concerted PCET reaction from the light state of the AppA BLUF domain is investigated. To model the simultaneous transfer of two protons in the reaction, two-dimensional potential energy surfaces for the double proton transfer are first calculated for the locally excited and charge transfer states, which are then used to obtain the vibrational wave function overlaps and the vibrational energy levels. Contributions to the PCET rate constant from each pair of vibronic states are then analyzed using the theory based on the Fermi's golden rule. We show that, the recently proposed light state structure of the BLUF domain with a tautomerized Gln63 residue is consistent with the concerted transfer of one electron and two protons. It is also found that, thermal fluctuations of the protein structure, especially the proton donor-acceptor distances, play an important role in determining the PCET reaction rate. © 2018 Wiley Periodicals, Inc.     

Preparation,rheological and drag reduction properties of hydrophobically associating polyacrylamide polymer

Hydrophobically associating polymer (HAMDP) was synthesized by using acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid and dodecyl 2-methylacrylate as main monomers. Dynamic rheometer and self-made simulation evaluation apparatus were used to test the rheological and drag reduction properties of HAMDP. With the mass concentration increased, the apparent viscosity of HAMDP increased. The critical aggregation concentration was 2.29g/L. With the changement of the strain, the elastic modulus was larger than viscous modulus. With the increment of HAMDP, the area of thixotropic loop increased. Compared with commercial polyacrylamide, the drag reduction rate of HAMDP could be up to 62.38%.     

Using tritium and 222Rn to estimate groundwater discharge and thawing permafrost contributing to surface water in permafrost regions on Qinghai-Tibet Plateau

Journal of Radioanalytical and Nuclear Chemistry - On the Qinghai-Tibet Plateau, permafrost degradation and associated release of permafrost meltwater has undoubtedly modified the annual and...     

TiO2/CNTs复合材料涂覆隔膜的制备及在锂硫电池中的应用

以金属有机框架材料MIL-125(Ti)为模板制备了多孔TiO₂, 同时引入碳纳米管, 得到碳纳米管交联包覆多孔TiO₂的三维导电复合材料. 将该复合材料涂覆在隔膜表面并应用于锂硫电池. 利用透射电子显微镜(TEM)、 扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等对材料的结构和组成进行了表征. 电化学测试结果表明,在0.5C(1C=1675 mA/g)倍率下, CNTs/S复合正极材料表现出高达1051.1 mA·h/g的放电容量, 循环150周后仍可保持在904.8 mA·h/g. 在1C倍率下, 放电容量最高可达1036.9 mA·h/g, 循环250周后仍有763.0 mA·h/g, 展现出了良好的倍率性能和循环稳定性.     

Toward Transition-Metal-Templated Construction of Arylated B4 Chains by Dihydroborane Dehydrocoupling

The reactivity of a diruthenium tetrahydride complex towards three selected dihydroboranes was investigated. The use of [DurBH₂] (Dur=2,3,5,6-Me₄C₆H) and [(Me₃Si)₂NBH₂] led to the formation of bridging borylene complexes of the form [(Cp*RuH)₂BR] (Cp*=C₅Me₅; 1 a : R=Dur; 1 b : R=N(SiMe₃)₂) through oxidative addition of the B−H bonds with concomitant hydrogen liberation. Employing the more electron-deficient dihydroborane [3,5-(CF₃)₂-C₆H₃BH₂] led to the formation of an anionic complex bearing a tetraarylated chain of four boron atoms, namely Li(THF)₄[(Cp*Ru)₂B₄H₅(3,5-(CF₃)₂C₆H₃)₄] ( 4 ), through an unusual, incomplete threefold dehydrocoupling process. A comparative theoretical investigation of the bonding in a simplified model of 4 and the analogous complex nido-[1,2(Cp*Ru)₂(μ-H)B₄H₉] ( I ) indicates that there appear to be no classical σ-bonds between the boron atoms in complex I , whereas in the case of 4 the B₄ chain better resembles a network of three B−B σ bonds, the central bond being significantly weaker than the other two.     

单组份有机太阳能电池纳米相分离调控新策略

<正>有机太阳能电池因其质轻、柔性、结构可调、可溶液加工等特点具有潜在的应用前景,近年来成为研究热点。其中,双组份或多组分的本体异质结型太阳能电池的研究最为深入,其能量转换效率已超过13%~(1,2);然而这类器件存在优化步骤多、稳定性差等缺点,不利于大面积制备。单组份太阳能电池中电子给体与受体通过共价键连接组成单     

C_(60)与MoO_3混合材料做空穴注入层的单层有机电致发光器件

我们制备研究了基于结构为氧化铟锡(ITO)/C_(60)(1.2nm):MoO_3(0.4nm)/1,3,5-三(1-苯基-1H-苯并咪唑-2-基)苯(TPBi):三(2-苯基吡啶)铱[Ir(ppy)_3](33%,90 nm)/LiF (0.7 nm)/Al (120 nm)的高效绿色磷光单层有机发光二极管(OLED)。分别将C_(60),MoO_3与C_(60):MoO_3混合物作为空穴注入层(HIL)作为对比。TPBi在发光层中起着主体以及电子传输材料的双重作用。在使用电子传输型主体的单层OLED中,空穴注入层性质对于调节电子/空穴注入以获得电荷载流子传输平衡起重要作用。因此,适当调节空穴注入层是实现高效单层OLED的关键因素。由于MoO_3较大的电子亲和能(6.37 eV)会诱导电子从C_(60)的最高占据分子轨道(HOMO)能级转移至MoO_3,从而形成C_(60)阳离子,并使得Mo元素的价态从+6降至+5,C_(60):MoO_3混合就可以较好的调节空穴注入性质。最终实现最大电流效率为35.88 cd·A~(-1)的单层有机发光器件。     

马兰戈尼效应在有机半导体成膜中的应用

<正>1背景介绍以有机发光二极管、有机太阳能电池和有机场效应晶体管为主的有机半导体薄膜器件,因在便携、可穿戴电子器件领域有巨大的应用前景,而逐渐成为无机半导体器件的一个重要补充。溶液法生长有机半导体薄膜工艺更使有机半导体器件的低成本、可在柔性基底上大面积制备的优点得到体现,因而受到广泛关注。但是,溶液法制备工艺也存在着诸多不足,比如被称为"咖啡环"效应的溶剂自然挥发造成的薄     

A zinc(Ⅱ) MOF based on secondary building units of infinite wavy-shaped chain exhibiting obvious luminescent sense effects

A new metal-organic framework (MOF),{[Zn_7 (BPS)_4 (OH)_6 (H_2O)_2]·5 H_2O]_n}(1), (H_2 BPS=4,4′-bibenzoic acid-2,2′-sulfone), based on a wavy and infinite chain-shaped secondary building units, has been synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction and further confirmed by PXRD, TGA and IR spectrum. The solid-state emission spectra reveal that compound 1 presents strong luminescence emission bands at room temperature. The fluorescent properties of compound 1 in diverse organic solvents indicated that 1 has palpable luminescent sense effects for DMF and DMAC.     

Protection of Li metal anode by surface-coating of PVDF thin film to enhance the cycling performance of Li batteries

The PVDF thin film on the surface of the lithium metal can highly suppress the lithium dendrites.