hydrogen bond

氢键
  • 文章类型: Journal Article
    标题化合物(系统名称:吡啶4-甲基-苯磺酸盐),C5H6N+·C7H7O3S-,是对甲苯磺酸的吡啶盐。在水晶里,经典的N-H_O氢键以及C-H_O触点将阳离子和阴离子实体连接到平行于ab平面的薄片中。
    The title compound (systematic name: pyridinium 4-methyl-benzene-sulfonate), C5H6N+·C7H7O3S-, is the pyridinium salt of para-toluene-sulfonic acid. In the crystal, classical N-H⋯O hydrogen bonds as well as C-H⋯O contacts connect the cationic and anionic entities into sheets lying parallel to the ab plane.
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  • 文章类型: Journal Article
    在标题化合物中,C14H14O3,芳环之间的二面角为39.76(9)°。在水晶里,摩尔分子缔合形成通过成对O-H-O氢键连接的中心对称酸-酸二聚体。当前单晶研究中的几何参数精度比以前的粉末衍射研究好一个数量级[Chattopadhyay等人。(2013年版)。CrystEngComm,15,1077-1085]。
    In the title compound, C14H14O3, the dihedral angle between the aromatic rings is 39.76 (9)°. In the crystal, the mol-ecules associate to form centrosymmetric acid-acid dimers linked by pairwise O-H⋯O hydrogen bonds. The precision of the geometric parameters in the present single-crystal study is about an order of magnitude better than the previous powder diffraction study [Chattopadhyay et al. (2013 ▸). CrystEngComm, 15, 1077-1085].
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  • 文章类型: Journal Article
    标题化合物,C15H15NO2在不对称单元中与两个摩尔分子结晶。在水晶里,两个摩尔分子通过成对O-H-O氢键缔合形成酸-酸二聚体。
    The title compound, C15H15NO2, crystallizes with two mol-ecules in the asymmetric unit. In the crystal, the two mol-ecules associate to form an acid-acid dimer by pairwise O-H⋯O hydrogen bonds.
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  • 文章类型: Journal Article
    理论MP2和B3LYPD3计算,以及实验基质隔离红外光谱研究,用于研究乙醇酸和水之间形成的1:1复合物。在五种计算预测的GA→H2O络合物形式中,最稳定的形式是在固体氩气中通过实验检测到的。该结构的特征在于两个分子间OH-O氢键,描绘了六元环,其中水既充当质子受体又充当质子供体。还初步建议在固体氩气中存在另外两种具有醇性OH基团作为质子供体的结构。
    Theoretical MP2 and B3LYPD3 calculations, as well as experimental matrix isolation infrared spectroscopy studies, were used to investigate the 1:1 complexes formed between glycolic acid and water. Out of five computationally predicted forms of GA⋯H2O complex the most stable one was detected experimentally in solid argon. This structure is characterized by two intermolecular OH⋯O hydrogen bonds depicting a six-member ring in which water acts both as a proton acceptor and as a proton donor. Two other structures with the alcoholic OH group acting as a proton donor are also tentatively suggested to be present in solid argon.
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  • 文章类型: Journal Article
    木质素,一种来自植物生物质的生物聚合物,由于其动态连接和官能团,被认为是开发自修复聚合物的非常有前途的物质。本文对木质素基自修复聚合物进行了全面的综述,从提取木质素的过程中,化学改性,合成技术,如通过可逆加成-断裂链转移(RAFT)聚合,与聚乙烯醇(PVA)和壳聚糖等聚合物交联,并与异氰酸酯反应以产生具有可逆相互作用的木质素基网络。这项工作还总结了自我修复能力的优化,例如包括动态共聚物,封装愈合剂如二环戊二烯和聚己内酯(PCL),和具有二硫化物或Diels-Alder(DA)部分的扩链剂。该材料的表征侧重于其通过氢键和动态再缔合恢复的能力,木质素的刚性结构改善了机械性能,和增强的耐温性。主要障碍涉及木质素提取的优化,增强聚合物相容性,并建立有效的合成和表征程序。总的来说,木质素作为自修复聚合物的可再生成分显示出巨大的潜力,有很多进一步发展的机会。
    Lignin, a biopolymer derived from plant biomass, is recognized as a highly promising substance for developing self-healing polymers owing to its dynamic linkages and functional groups. This paper provides a thorough review of lignin-based self-healing polymer, from the process of extracting lignin, chemical modification, synthesis techniques such as via reversible addition-fragmentation chain transfer (RAFT) polymerization, crosslinking with polymers like polyvinyl alcohol (PVA) and chitosan, and reactions with isocyanates to create lignin-based networks with reversible interactions. This work also summarizes the optimization of self-healing ability, such as including dynamic copolymers, encapsulating healing agents like dicyclopentadiene and polycaprolactone (PCL), and chain extenders with disulfide or Diels-Alder (DA) moieties. The material\'s characterization focuses on its capacity to recover via hydrogen bonding and dynamic re-associations, improved mechanical properties from lignin\'s rigid structure, and enhanced temperature resistance. Primary obstacles involve the optimization of lignin extraction, enhancement of polymer compatibility, and the establishment of efficient procedures for synthesis and characterization. Overall, lignin shows great potential as a renewable component of self-healing polymers, with plenty of opportunities for further development.
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  • 文章类型: Journal Article
    结构,机械,电子,振动,通过密度泛函理论研究了新型高能低灵敏度的5,5'-二硝基氨基-3,3'-偶氮-恶二唑4,7-二氨基吡啶并[4,5-c]呋喃盐的氢键性质。计算的振动特性表明,低频模式主要由-NO2组的振动贡献,高频模式主要由-NH2基团的振动和使阳离子质子化的N7-H3键贡献。此外,据分析,第一个键断裂可能是N-NO2键。计算的氢键性质表明,水分子与阳离子之间的氢键为N7-H3...O5(1.563µ),这是所有氢键中最短的氢键。这种非常短的氢键的存在使N7-H3和H6-O5键在高频下抗破坏,强调氢键在稳定含能材料结构中的关键作用。鉴于缺乏电子的实验和理论数据,机械,到目前为止,材料的振动特性,我们的计算为高能量和低灵敏度的离子盐提供了有价值的理论见解。
    所有计算均基于密度泛函理论(DFT)进行,并在CASTEP代码中实现。利用保模伪势来描述平面波扩展函数,而广义梯度近似(GGA)内的PBE函数用于表征交换相关相互作用。此外,色散校正采用Grimme的DFT-D方法。
    UNASSIGNED: The structure, mechanical, electronic, vibration, and hydrogen bonding properties of a novel high-energy and low-sensitivity 5, 5\'-dinitroamino-3, 3\'-azo-oxadiazole 4, 7-diaminopyridazino [4, 5-c] furoxan salt have been studied by density functional theory. The calculated vibrational properties show that the low-frequency mode is mainly contributed by the vibration of the -NO2 group, and the high-frequency mode is mainly contributed by the vibration of the -NH2 group and the N7-H3 bond which protonates the cation. In addition, it is analyzed that the first bond to break may be the N-NO2 bond. The calculated hydrogen bond properties indicate that the hydrogen bond between water molecules and cations is N7-H3… O5 (1.563 Å), which is the shortest hydrogen bond among all hydrogen bonds. The presence of this exceptionally short hydrogen bond renders the N7-H3 and H6-O5 bonds resistant to disruption at high frequencies, underscoring the pivotal role of hydrogen bonding in stabilizing the structure of energetic materials. Given the absence of experimental and theoretical data on the electronic, mechanical, and vibrational properties of the material thus far, our calculations offer valuable theoretical insights into the ionic salts of high energy and low sensitivity.
    UNASSIGNED: All calculations have been carried out based on density functional theory (DFT) and implemented in the CASTEP code. The mode-conserving pseudopotential is utilized to describe the plane wave expansion function, while the PBE functional within the generalized gradient approximation (GGA) is employed to characterize the exchange-correlation interaction. Additionally, dispersion correction is applied using Grimme\'s DFT-D method.
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  • 文章类型: Journal Article
    纤维素基气凝胶为含油废水处理提供了卓越的前景,但低机械强度和有限的应用功能的挑战仍然存在。受动物骨骼和竹茎中渐变多孔结构的启发,我们首先在这里报道了一种逐步溶剂扩散诱导的相分离方法,用于构建梯度孔密度三维(3D)纤维素支架(GPDS)。有利于调节反溶剂与纤维素溶液中离子液体(IL)之间的竞争性氢键,GPDS表现出沿着溶剂扩散方向逐渐减小的主要通道尺寸和增加的次要孔隙量。这些赋予GPDS具有低密度(0.019g/cm)和超强度(高达870KPa)的特征。GPDS在油水分离领域的应用取得了显著成效,包括油/有机溶剂吸收(13-25g/gGPDS),不混溶的油水混合物分离(效率高达99.8%,通量>2000L/m2·h),和表面活性剂稳定的水包油乳液(效率高达97.7%)。此外,简单的疏水处理进一步实现了油包水乳液的高效分离(效率98.5%)。制造的GPDS相应地实现了在油水分离领域的多功能应用。因此,为构建3D纤维素多孔支架作为含油废水处理中的吸附材料开辟了一条新途径。
    Cellulose-based aerogels offer exceptional promise for oily wastewater treatment, but the challenge of low mechanical strength and limited application functions persists. Inspired by the graded porous structures in the animal skeleton and bamboo stem, we firstly report here a stepwise solvent diffusion-induced phase separation approach for constructing the gradient pore-density three-dimensional (3D) cellulose scaffold (GPDS). Benefiting from the regulation of competitive hydrogen bonding between the anti-solvents and the ionic liquid (IL) in cellulose solution, GPDS exhibits the decreased major channels size and increased minor pores amount gradually along the solvent diffusion direction. These endow GPDS with the characteristics of low density (0.019 g/cm) and super strength (high up to 870 KPa). The application of GPDS in the field of oil-water separation has achieved remarkable results, including oil/organic solvent absorption (13-25 g/gGPDS), immiscible oil-water mixture separation (high efficiency up to 99.8 %, flux > 2000 L/m2·h), and surfactant-stabilized oil-in-water emulsion (efficiency up to 97.7 %). Moreover, a simple hydrophobic treatment further realizes the efficient separation of water-in-oil emulsion (98.5 % efficiency). The as-fabricated GPDS accordingly achieves the multifunctional application in oil-water separation field. Thus, a new avenue is opened to construct 3D cellulose porous scaffold as adsorbent materials in oily wastewater treatment.
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  • 文章类型: Journal Article
    高水分挤压技术具有高效、低能耗等优点,是一种很有前途的南极磷虾肉加工策略。因此,本研究旨在制备不同含水量下具有丰富纤维结构的高水分纹理南极磷虾肉(HMTAKM)(53%,57%,和61%),并揭示水分子的结合和分布规律,与HMTAKM的纤维结构密切相关,研究较少。氢键网络结果表明存在至少两种或更多种类型的具有不同氢键的水分子。增加HMTAKM的含水量促进了水分子与蛋白质分子之间氢键的形成,导致β-折叠过渡到α-螺旋。这些发现为南极磷虾提供了一种新颖可行的加工技术,并对高水分纹理蛋白的纤维形成有了新的了解。
    High-moisture extrusion technique with the advantage of high efficiency and low energy consumption is a promising strategy for processing Antarctic krill meat. Consequently, this study aimed to prepare high-moisture textured Antarctic krill meat (HMTAKM) with a rich fiber structure at different water contents (53 %, 57 %, and 61 %) and to reveal the binding and distribution regularity of water molecules, which is closely related to the fiber structure of HMTAKM and has been less studied. The hydrogen-bond network results indicated the presence of at least two or more types of water molecules with different hydrogen bonds. Increasing the water content of HMTAKM promoted the formation of hydrogen bonds between the water molecules and protein molecules, leading to the transition of the β-sheet to the α-helix. These findings offer a novel viable processing technique for Antarctic krill and a new understanding of the fiber formation of high-moisture textured proteins.
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  • 文章类型: Journal Article
    本研究评估了魔芋葡甘聚糖(KGM)对大豆分离蛋白(SPI)聚集及其凝胶相关结构和性质的影响。拉曼结果表明,KGM促进SPI重排形成更多的β-折叠,有助于有序结构的形成。原子力显微镜,共聚焦激光扫描显微镜,小角度X射线散射结果表明,KGM减小了SPI颗粒的尺寸,缩小它们的大小分布,松开SPI颗粒堆积形成的大聚集体,提高凝胶体系的均匀性。随着KGM和SPI分子之间氢键的增强,获得了发达的网络结构,进一步降低了SPI凝胶的固定化水含量(T22),提高了SPI凝胶的保水性(WHC)。此外,这种凝胶结构显示出改进的凝胶硬度和耐小和大变形。这些发现有助于设计和生产具有所需性能的基于SPI的凝胶。
    This study assessed the effect of konjac glucomannan (KGM) on the aggregation of soy protein isolate (SPI) and its gel-related structure and properties. Raman results showed that KGM promoted the rearrangement of SPI to form more β-sheets, contributing to the formation of an ordered structure. Atomic force microscopy, confocal laser scanning microscopy, and small-angle X-ray scattering results indicated that KGM reduced the size of SPI particles, narrowed their size distribution, and loosened the large aggregates formed by the stacking of SPI particles, improving the uniformity of gel system. As the hydrogen bonding between the KGM and SPI molecules enhanced, a well-developed network structure was obtained, further reducing the immobilized water\'s content (T22) and increasing the water-holding capacity (WHC) of SPI gel. Furthermore, this gel structure showed improved gel hardness and resistance to both small and large deformations. These findings facilitate the design and production of SPI-based gels with desired performance.
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  • 文章类型: Journal Article
    在超高清显示器中,非常需要具有国际委员会Ey≤0.08坐标的高性能深蓝色发射器。在这里,我们设计并合成了一种高效的D-π-A深蓝色发射器,2-(6-([1,1\':3\',1\'\'-三联苯]-5\'-基)吡啶-3-基)-1-苯基-1H-菲并[9,10-d]咪唑(mPTPH),利用分子内氢键(H键)和杂化激发态的协同作用。单晶结构分析证实,存在分子内和分子间H键相互作用,可以抑制结构振动并提高光致发光效率。光物理和理论结果表明,mPTPH表现出杂化的局部和电荷转移(HLCT)特征,具有很强的深蓝色发射。最终,基于mPTPH的非掺杂器件表现出20610cdm-2的最高亮度。掺杂器件实现了5.4%的高最大外量子效率和低效率滚降,深蓝色发射峰为413nm,CIE坐标为(0.16,0.08)。
    High performance deep-blue emitters with a Commission International de l\'Eclairage (CIE) coordinate of CIEy ≤ 0.08 are highly desired in ultrahigh-definition displays. Herein, we designed and synthesized an efficient D‒π‒A deep-blue emitter, 2-(6-([1,1\':3\',1\'\'-terphenyl]-5\'-yl)pyridin-3-yl)-1-phenyl-1H-phenanthro[9,10-d] imidazole (mPTPH), using the synergistic effect of intramolecular hydrogen bond (H-bond) and hybridized excited state. Single-crystal structure analysis confirmed that there exist intra- and intermolecular H-bond interactions which could inhibit the structure vibration and increase photoluminescence efficiency. The photophysical and theoretical results show that mPTPH exhibited hybridized local and charge-transfer (HLCT) feature with strong deep-blue emission. Ultimately, the non-doped device based on mPTPH exhibited high maximum luminance of 20610 cd m-2. The doped device achieved high maximum external quantum efficiency of 5.4% and small efficiency roll-off with deep-blue emission peak of 413 nm and CIE coordinate of (0.16, 0.08).
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