single-crystal X-ray diffraction

单晶 X射线衍射
  • 文章类型: Journal Article
    结合来自同一样品的粉末衍射数据,成功地进行了LaAlO3拟摩面体孪晶晶体的域分辨同步加速器单晶X射线衍射研究。从一个单晶确定从微米到纳米到原子尺度的多尺度结构信息。在低于400K的温度下,畴比几乎没有变化,表明畴壁没有运动。在450至700K的温度范围内观察到指示畴壁运动的畴比变化,这与之前的机械测量结果一致。还发现四个孪生组分的比例变得相等(25%),低于相变温度。这些发现对于与LaAlO3相关的领域工程和理论研究具有重要意义。除第一加热过程至840K外,在加热和冷却循环中保留了畴比的温度依赖性。因此,加热到840K后的畴结构是晶体固有的。通过晶胞参数校准和域分辨结构分析确定了精确的结构参数。推导了从双晶数据中校准晶胞参数的方法,并将其用于解决当前和以前研究中单晶和粉末数据之间的晶胞参数不一致的问题。
    A domain-resolved synchrotron single-crystal X-ray diffraction study of a LaAlO3 pseudo-merohedral twin crystal was successfully carried out in combination with powder diffraction data from the same sample. Multiscale structure information ranging from micro- to nano- to atomic scale was determined from one single crystal. There is almost no change of domain ratios at temperatures of less than 400 K indicating no movement of the domain wall. The changes in domain ratio indicating domain-wall movement were observed in the temperature range of 450 to 700 K, which is consistent with the result of the previous mechanical measurement. It is also found that the ratio of four twin components becomes equal (25%), just below phase transition temperature. These findings are important for domain engineering and theoretical studies related to LaAlO3. The temperature dependence of domain ratio was preserved in the heating and cooling cycle except for the first heating process to 840 K. Therefore, the domain structure after heating to 840 K is intrinsic to the crystal. Accurate structure parameters were determined through unit-cell parameter calibration and domain-resolved structure analysis. The method for calibration of unit-cell parameters from twin crystal data was derived and used to solve the inconsistent unit-cell parameters between single crystal and powder data in the present and previous studies.
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  • 文章类型: Journal Article
    使用实验模型的统计设计对晶体海绵{[(ZnI2)3(tpt)2·x(溶剂)]n}方法的分析物浸泡条件的研究提供了对实验变量影响的基本见解。这种方法侧重于通过60个实验(20个独特条件)测试的单个分析物,以确定成功和整体客体结构质量的主要影响。这被用作开发新型分子结构分级系统的基础,该系统可以量化客体交换质量。
    Investigation of the analyte soaking conditions on the crystalline sponge {[(ZnI2)3(tpt)2·x(solvent)]n} method using a statistical design of experiments model has provided fundamental insights into the influence of experimental variables. This approach focuses on a single analyte tested via 60 experiments (20 unique conditions) to identify the main effects for success and overall guest structure quality. This is employed as a basis for the development of a novel molecular structure grading system that enables the quantification of guest exchange quality.
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  • 文章类型: Journal Article
    获得了两种基于5-硝基吡啶甲酸配体(5-npic)的新镧系元素配合物,并对其进行了充分表征。单晶X射线衍射表明,这些化合物与Dy配合物同构,以前由我们出版,基于双核单体与扩展的氢键网络连接在一起,提供[Ln2(5-npic)6(H2O)4]·(H2O)2的最终化学式,其中Ln=Dy(1),Gd(2),Tb(3)。初步的光致发光研究显示,所有配合物都以配体为中心的发射。在前列腺癌细胞系(PC-3;第二常见的男性癌性疾病)中测定了这些材料的潜在抗肿瘤活性,显示出显着的抗癌活性(在500μg·mL-1时为50-60%)。反过来,两者的高生物相容性,人类免疫学HL-60细胞中的复合物及其前体,有证据。鉴于由游离5-npic配体(〜40-50%)提供的肿瘤细胞系中最强的毒性作用,整体抗癌复合物的性能似乎是由该分子的存在引发的。
    Two new lanthanide-complexes based on the 5-nitropicolinate ligand (5-npic) were obtained and fully characterized. Single-crystal X-ray diffraction revealed that these compounds are isostructural to a Dy-complex, previously published by us, based on dinuclear monomers link together with an extended hydrogen bond network, providing a final chemical formula of [Ln2(5-npic)6(H2O)4]·(H2O)2, where Ln = Dy (1), Gd (2), and Tb (3). Preliminary photoluminescent studies exhibited a ligand-centered emission for all complexes. The potential antitumoral activity of these materials was assayed in a prostatic cancer cell line (PC-3; the 2nd most common male cancerous disease), showing a significant anticancer activity (50-60% at 500 μg·mL-1). In turn, a high biocompatibility by both, the complexes and their precursors in human immunological HL-60 cells, was evidenced. In view of the strongest toxic effect in the tumoral cell line provided by the free 5-npic ligand (~ 40-50%), the overall anticancer complex performance seems to be triggered by the presence of this molecule.
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  • 文章类型: Journal Article
    单磺化偶氮染料的五种铵盐形式的结构,4-(2-苯基二嗪-1-基)苯磺酸酯的衍生物,通式为[NH4][O3S(C6H4)NN(C6H3)RR']·XH2O[R=OH,给出了NH2或N(C2H4OH)2;R1'=H或OH]。全部形成简单的层状结构,具有交替的疏水(有机)和亲水(阳离子,溶剂和极性基团)层。为了评估铵阳离子与M+离子的同构行为,将这些结构的填料与文献实例进行了比较。为了帮助进行比较,本文还提供了单磺化偶氮染料的四种钾盐形式的相应结构。在五种铵盐中,发现三种具有同构等同物。在两种情况下,这种等价物是钾盐形式,在一种情况下,它是铷盐形式。离子堆积以及晶胞对称性和尺寸的等结构性可以容忍铵离子与共形成物类形成的相互作用类型与钾或铷离子不同的情况。没有发现钠盐形式与任何铵当量是同构的。然而,对于由一种偶氮阴离子物种的铵盐和ru盐形式以及不同偶氮物种的钠盐和银盐形式组成的一组,发现了单个疏水层内阴离子堆积的相似性。
    The structures of five ammonium salt forms of monosulfonated azo dyes, derivatives of 4-(2-phenyldiazen-1-yl)benzenesulfonate, with the general formula [NH4][O3S(C6H4)NN(C6H3)RR\']·XH2O [R = OH, NH2 or N(C2H4OH)2; R\' = H or OH] are presented. All form simple layered structures with alternating hydrophobic (organic) and hydrophilic (cation, solvent and polar groups) layers. To assess for isostructural behaviour of the ammonium cation with M+ ions, the packing of these structures is compared with literature examples. To aid this comparison, the corresponding structures of four potassium salt forms of the monosulfonated azo dyes are also presented herein. Of the five ammonium salts it is found that three have isostructural equivalents. In two cases this equivalent is a potassium salt form and in one case it is a rubidium salt form. The isostructurality of ion packing and of unit-cell symmetry and dimensions tolerates cases where the ammonium ions form somewhat different interaction types with coformer species than do the potassium or rubidium ions. No sodium salt forms are found to be isostructural with any ammonium equivalent. However, similarities in the anion packing within a single hydrophobic layer are found for a group that consists of the ammonium and rubidium salt forms of one azo anion species and the sodium and silver salt forms of a different azo species.
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  • 文章类型: Journal Article
    BipoladiensA-E(1-5),五种新的ophiobolin衍生的酯萜类化合物,和已知的化合物6(双极霉素R)从植物病原真菌BiParlismaydis的培养物中分离出来。根据全面的光谱分析阐明了它们的结构和绝对构型,HRESIMS,电子圆二色性(ECD)计算,和单晶X射线衍射分析。值得注意的是,化合物1具有未描述的四环5/8/5/7稠合碳骨架,化合物2具有罕见的多环笼环体系。通过一系列氧化和环化反应,从6开始提出了1的生物合成途径。化合物6对A549细胞系显示出优异的抗增殖和凋亡诱导作用。此外,化合物5和6对蜡样芽孢杆菌表现出明显的抗菌能力,金黄色葡萄球菌,和表皮葡萄球菌.这些发现不仅发展了ophiobolin-sisterterpenoid的化学和生物活性多样性,而且为促进天然产物在食品病原体控制中的应用提供了思路。
    Bipoladiens A-E (1-5), five new ophiobolin-derived sesterterpenoids, and a known compound 6 (bipolaricin R) were isolated from the cultures of the phytopathogenic fungus Bipolaris maydis. Their structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, HRESIMS, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction analyses. Notably, compound 1 has an undescribed tetracyclic 5/8/5/7 fused carbon skeleton, and compound 2 possesses a rare multicyclic caged ring system. The biosynthetic pathway of 1 was proposed starting from 6 via a series of oxidation and cyclization reactions. Compound 6 showed excellent antiproliferation and apoptosis induction effects against A549 cell line. Additionally, compounds 5 and 6 exhibited noticeable antimicrobial ability against Bacillus cereus, Staphylococcus aureus, and Staphylococcus epidermidis. These findings not only developed the chemical and bioactivities diversities of ophiobolin-sesterterpenoid but also provided an idea to boost the application of natural products in the control of food pathogens.
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  • 文章类型: Journal Article
    通过修饰/未修饰的氨基酸的自组装形成的纳米结构具有在几种生物/非生物应用中有用的潜力。在这方面,γ-氨基酸提供的构象空间越大,由于它们额外的骨架扭转自由度和增强的蛋白水解稳定性,与他们的α-同行相比,应该探索。不过,通过利用源自苯丙氨酸(Phe)的主链同源的单取代γ-氨基酸,开发了修饰的基于单氨基酸的纳米材料,例如纳米带或水凝胶。能够容纳溶剂分子的单个基于γ-氨基酸的多孔纳米结构的实例并不真正已知。修饰的γ4(R)Phe残基的晶体结构,Boc-γ4(R)Phe-OH,在不同的温度下,表明氢键结合的水分子在亲水纳米通道内形成导线。通过分析在不同温度点获得的单晶结构进行的自然键合轨道(NBO)计算结果,研究了水丝与通道内壁之间的分子间相互作用与温度变化的关系。NBO结果显示,从325K开始,水线中的水-水相互作用的强度越来越弱,然而,对于水-内壁的相互作用,它变得更强,表明水分子的取向随温度发生了有利的变化,对于后者。
    Nanostructures formed by the self-assembly of modified/unmodified amino acids have the potential to be useful in several biological/nonbiological applications. In that regard, the greater conformational space provided by γ-amino acids, owing to their additional backbone torsional degrees of freedom and enhanced proteolytic stability, compared to their α-counterparts, should be explored. Though, modified single amino acid-based nanomaterials such as nanobelts or hydrogels are developed by utilizing the monosubstituted γ-amino acids derived from the backbone homologation of phenylalanine (Phe). Examples of a single γ-amino acid-based porous nanostructure capable of accommodating solvent molecules are not really known. The crystal structures of a modified γ4(R)Phe residue, Boc-γ4(R)Phe-OH, at different temperatures, showed that hydrogen-bonded water molecules are forming a wire inside hydrophilic nanochannels. The dynamics of intermolecular interactions between the water wire and the inner wall of the channel with relation to the temperature change was investigated by analyzing the natural bonding orbital (NBO) calculation results performed with the single crystal structures obtained at different temperature points. The NBO results showed that from 325 K onward, the strength of water-water interactions in the water wire are getting weaker, whereas, for the water-inner wall interactions, it getting stronger, suggesting a favorable change in the orientation of water molecules with temperatures, for the latter.
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  • 文章类型: Journal Article
    小分子活性药物成分的单晶X射线衍射分析是确认分子连通性的关键技术,包括绝对立体化学,以及固态形式。然而,获得适用于活性药物成分的X射线衍射分析的单晶可能是实验上费力的,特别是考虑到多种固态形式(溶剂化物,水合物和多晶型物)。近年来,探索小分子实验结晶空间的方法经历了“阶跃变化”,导致新的高通量技术变得可用。这里,高通量包封纳米液滴结晶在一系列六种二氢吡啶中的应用,钙通道阻滞剂用于治疗高血压相关疾病,被描述。这种方法允许对每个分子平行进行288个单独的结晶实验,导致快速获得所有六种二氢吡啶的晶体和随后的晶体结构,以及揭示了硝苯地平的新溶剂化物多晶型物(1,4-二恶烷溶剂化物)和第一个已知的尼莫地平溶剂化物(DMSO溶剂化物)。这项工作进一步证明了现代高通量结晶方法在探索活性药物成分的固态景观中的力量,以促进通过单晶X射线衍射进行晶型发现和结构分析。
    Single-crystal X-ray diffraction analysis of small molecule active pharmaceutical ingredients is a key technique in the confirmation of molecular connectivity, including absolute stereochemistry, as well as the solid-state form. However, accessing single crystals suitable for X-ray diffraction analysis of an active pharmaceutical ingredient can be experimentally laborious, especially considering the potential for multiple solid-state forms (solvates, hydrates and polymorphs). In recent years, methods for the exploration of experimental crystallization space of small molecules have undergone a `step-change\', resulting in new high-throughput techniques becoming available. Here, the application of high-throughput encapsulated nanodroplet crystallization to a series of six dihydropyridines, calcium channel blockers used in the treatment of hypertension related diseases, is described. This approach allowed 288 individual crystallization experiments to be performed in parallel on each molecule, resulting in rapid access to crystals and subsequent crystal structures for all six dihydropyridines, as well as revealing a new solvate polymorph of nifedipine (1,4-dioxane solvate) and the first known solvate of nimodipine (DMSO solvate). This work further demonstrates the power of modern high-throughput crystallization methods in the exploration of the solid-state landscape of active pharmaceutical ingredients to facilitate crystal form discovery and structural analysis by single-crystal X-ray diffraction.
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  • 文章类型: Journal Article
    在4f元素之间具有金属-金属键的分子化合物的合成被认为是镧系元素金属化学中令人着迷的里程碑之一。由于对其磁性的兴趣,此类研究的主要重点是重镧系元素,而轻镧系元素之间的结合仍未探索。在这项工作中,作为早期镧系元素之间金属-金属键合的案例研究,证明了Nd-二金属富勒烯中的Nd-Nd键。结合实验和计算研究证明,原始Nd2@C80具有开放的壳结构,单电子占据Nd─Nd键合轨道。Nd2@C80通过单电子还原并进一步通过向[Nd2@C80]-添加亲电子CF3来稳定。单晶X射线衍射揭示了具有D5h-C80和Ih-C80碳笼的两种Nd2@C80(CF3)异构体的形成,均具有单电子Nd-Nd键,长度为3.78-3.79µ。分析了外面体CF3基团和内面体金属二聚体在确定加合物分子结构中的相互影响。与Tb或Dy类似物不同,是强单分子磁体,具有高磁化阻挡温度,Nd2@Ih-C80(CF3)中磁化的缓慢弛豫仅在3K以下且存在磁场的情况下通过异相磁化率即可检测到。
    Synthesis of molecular compounds with metal-metal bonds between 4f elements is recognized as one of the fascinating milestones in lanthanide metallochemistry. The main focus of such studies is on heavy lanthanides due to the interest in their magnetism, while bonding between light lanthanides remains unexplored. In this work, the Nd─Nd bonding in Nd-dimetallofullerenes as a case study of metal-metal bonding between early lanthanides is demonstrated. Combined experimental and computational study proves that pristine Nd2 @C80 has an open shell structure with a single electron occupying the Nd─Nd bonding orbital. Nd2 @C80 is stabilized by a one-electron reduction and further by the electrophilic CF3 addition to [Nd2 @C80 ]- . Single-crystal X-ray diffraction reveals the formation of two Nd2 @C80 (CF3 ) isomers with D5h -C80 and Ih -C80 carbon cages, both featuring a single-electron Nd─Nd bond with the length of 3.78-3.79 Å. The mutual influence of the exohedral CF3 group and endohedral metal dimer in determining the molecular structure of the adducts is analyzed. Unlike Tb or Dy analogs, which are strong single-molecule magnets with high blocking temperature of magnetization, the slow relaxation of magnetization in Nd2 @Ih -C80 (CF3 ) is detectable via out-of-phase magnetic susceptibility only below 3 K and in the presence of magnetic field.
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  • 文章类型: Journal Article
    硅酸盐钙钛矿,矿物名称为Bridgmanite,是地球下地幔中最丰富的矿物。我们研究了两种钙钛矿型富Fe3相的晶体结构和状态方程,FeMg0.5Si0.5O3和Fe0.5Mg0.5Al0.5Si0.5O3,在高压下,采用单晶X射线衍射和同步加速器穆斯堡尔谱。我们在高压下解决了它们的晶体结构,发现FeMg0.5Si0.5O3相采用了一种新型的单斜双钙钛矿结构,在高于12GPa的压力下具有P21/n的空间群,而Fe0.5Mg0.5Al0.5Si0.5O3相采用正交钙钛矿结构,在8GPa以上的压力下具有Pnma的空间群。在高于40GPa的压力下,压力在FeMg0.5Si0.5O3相的(Fe0.7,Mg0.3)O6八面体位置中引起Fe3的铁自旋转变。Fe0.5Mg0.5Al0.5Si0.5O3相没有观察到铁自旋转变,因为所有的Fe3+离子都位于双棱柱位点,其体积大于(Al0.5,Si0.5)O6的八面体位点。
    Silicate perovskite, with the mineral name bridgmanite, is the most abundant mineral in the Earth\'s lower mantle. We investigated crystal structures and equations of state of two perovskite-type Fe3+-rich phases, FeMg0.5Si0.5O3 and Fe0.5Mg0.5Al0.5Si0.5O3, at high pressures, employing single-crystal X-ray diffraction and synchrotron Mössbauer spectroscopy. We solved their crystal structures at high pressures and found that the FeMg0.5Si0.5O3 phase adopts a novel monoclinic double-perovskite structure with the space group of P21/n at pressures above 12 GPa, whereas the Fe0.5Mg0.5Al0.5Si0.5O3 phase adopts an orthorhombic perovskite structure with the space group of Pnma at pressures above 8 GPa. The pressure induces an iron spin transition for Fe3+ in a (Fe0.7,Mg0.3)O6 octahedral site of the FeMg0.5Si0.5O3 phase at pressures higher than 40 GPa. No iron spin transition was observed for the Fe0.5Mg0.5Al0.5Si0.5O3 phase as all Fe3+ ions are located in bicapped prism sites, which have larger volumes than an octahedral site of (Al0.5,Si0.5)O6.
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  • 文章类型: Journal Article
    皮肤伤口易于细菌感染和生长。这里报道了一种抗菌局部水凝胶,其可以充当自药物递送(SDD)系统。当与Zn(NO3)2和一系列非甾体抗炎药(NSAID)反应时,由咪唑/苯并咪唑衍生物衍生的两个双齿配体(L2/L1)产生结晶产物,用单晶X射线衍射(SXRD)对其进行了表征。当二齿配体是水不溶性L2时,结晶产物的成分的简单混合(化学计量由相应的晶体结构指导)产生了水性凝胶(DMSO/水),而水溶性L1在类似条件下容易产生水凝胶。采用动态流变学和扫描电子显微镜(SEM)表征凝胶。区域抑制直径,最小抑制浓度(MIC),最小杀菌浓度(MBC),溶血数据表明,在水凝胶剂中,发现来自L1,甲氯芬酸和Zn(NO3)2的L1MEC对革兰氏阴性菌大肠杆菌最好。相应的水凝胶L1MEC_HG和涂覆有水凝胶的干布绷带片也显示出明显的抗大肠杆菌活性。L1MEC_HG对大肠杆菌的抗菌性能,由此证明,与开发抗菌SDD系统有关,因为据报道大肠杆菌存在于感染的伤口中。
    A skin wound is prone to bacterial infection and growth. An antibacterial topical hydrogel that can act as a self-drug-delivery (SDD) system is reported here. Two bidentate ligands (L2/L1) derived from imidazole/benzimidazole derivatives when reacted with Zn(NO3)2 and a series of nonsteroidal-anti-inflammatory drugs (NSAIDs) produced crystalline products, which were characterized by single-crystal X-ray diffraction (SXRD). Simple mixing of the ingredients of the crystalline products (stoichiometry guided by the corresponding crystal structure) produced an aqueous gel (DMSO/water) when the bidentate ligand was water-insoluble L2, whereas water-soluble L1 readily produced hydrogels under similar conditions. Dynamic rheology and scanning electron microscopy (SEM) were employed to characterize the gels. Zone inhibition diameters, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and hemolysis data suggested that among the hydrogelators, L1MEC derived from L1, meclofenac and Zn(NO3)2, was found to be the best against the Gram-negative bacteria Escherichia coli. The corresponding hydrogel L1MEC_HG and a piece of a dried cloth bandage coated with the hydrogel also showed appreciable activity against E. coli. The antibacterial property of L1MEC_HG against E. coli, thus demonstrated, is relevant in developing an antibacterial SDD system because E. coli is reported to be present in infected wounds.
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