Single-crystal Diffraction Research Articles

Increasing completeness in single-crystal high-pressure diffraction experiments by pre-orienting crystals

Increasing completeness in single-crystal high-pressure diffraction experiments by pre-orienting crystals

Novel benzotriazole-benzimidazole metal complexes: structure-activity relationship, synthesis, characterization, and antidiabetic activity

To investigate the relationship between structure and antidiabetic activity, four novel metal complexes [Cu2(ebmb)2Cl4] (1), [Zn2(ebmb)Cl4] (2), [Cu(ebmb)SO4]n (3) and [Cu(mbmb)SO4]n (4) have been synthesized by 1-[(2-ethyl-1H-benzimidazole- 1-yl)methyl]-1H-benzotriazole (ebmb) and 1-[(2-methyl-1H-benzimidazole-1-yl) methyl]-1H-benzotriazole (mbmb), and the antidiabetic activities of them have been evaluated. The X-ray single crystal diffraction analysis reveals that complexes 1-2 are binuclear complexes and isostructural expect the different central metal. Complexes 3-4 possess the same central metal but different ligands, and they have very similar structure and they both possess one-dimensional chain structure. We assessed the in vitro antidiabetic activities of the complexes. The results of the α-amylase and α-glucosidase inhibition assays showed that complexes 1 and 4 possessed strongest inhibitory activities with the IC50 values of 1.29mM±0.04 (1) and 4.69mM±0.43 (4) for α-amylase, 0.75±0.04μM (1) and 1.63±0.11μM (4) for α-glucosidase. Finally, we evaluated the effect of complexes 1 and 4 on the glucose consumption of insulin resistant (IR) HepG2 cells, the results showed that both two complexes can improve the IR state of HepG2 cells, the glucose consumption of complex 1-treated IR-HepG2 cells and complex 4-treated IR-HepG2 cells were 1.3 times and 1.18 times as much as the model group, respectively. What's more, the structure-function relationship of complexes had also been discussed in this paper.

A New Metal–Organic Complex (Br‐C6H3(I)‐NH2)2CuBr2: Growth and Structural Properties

AbstractMetal–organic complexes are a class of promising functional materials, especially for thermoelectric materials. Here, for the first time, a new metal–organic complex (Br‐C6H3(I)‐NH2)2CuBr2 is designed and synthesized. (Br‐C6H3(I)‐NH2)2CuBr2 single crystals are obtained via a vapor diffusion method. X‐ray single crystal diffraction results indicate that the material crystallizes in the triclinic system, with the space group P and the following crystal structural data: a = 4.7825(7) Å, b = 8.8072(12) Å, c = 11.4652(16) Å, α = 80.450(5)°, β = 81.699(6)°, γ = 80.824(5)°, V = 466.67(11) Å3, and Z = 1. The structure of packing in the crystal is alternatively arranged composed of inorganic layers of CuBr2 and organic layers of Br‐C6H3(I)‐NH2. The molecular geometries structure of the crystal is discussed via intra and intermolecular interactions and molecular geometry. This work may provide a new material for new emerging high‐performance thermoelectric materials.

Cocrystal of 4-Nitrophenol and 2,1,3-Benzoselenadizole

The 1:1 cocrystal of 4-nitrophenol (NP) and 2,1,3-benzoselenadiazole (BSA) was successfully synthesized. The X-ray single-crystal diffraction analysis revealed that the structure contained a [Se–N]2 cyclic supramolecular synthon. The synthons were connected into a one-dimensional ribbon by O–H···N hydrogen bonds and N–Se···O chalcogen bonds. Furthermore, adjacent ribbons were stabilized by the π···π stacking interactions between two 2,1,3-benzoselenadiazole molecules, leading to the formation of a two-dimensional network.

In situ reduction synthesis of quinoline-based copper(I) complexes: “Self-activating” chemical nuclease, antioxidation and anticancer activity

Two new Cu(І) complexes, [Cu2(L1)2(μ-Br)2] (1) and [Cu2(L1)2(μ-Cl)2] (2) were synthesized from Cu(II) halogen salts and the reduced Schiff base ligand. Stable Cu(І) complexes were obtained via in situ reduction of Cu(II) to Cu(I) and the CN was oxidize to C = N in the ligand. The structures of two complexes were characterized by X-ray single crystal diffraction analysis as well as IR and UV–Vis spectra. The two complexes have potential antioxidant capacity and exhibit efficiently self-activated DNA cleavage activity and hydroxyl radical ROS cleavage mechanism. MTT was used to assay cytotoxicity of the complexes toward a series of tumor cell and HUVEC cell lines. Both complexes exhibited higher selective cytotoxicity against tumor cells than normal cells, which is significantly superior to the positive control. The complexes could induce cell apoptosis via mitochondrial pathway by increase of ROS levels and decrease of mitochondrial membrane potential (Δψm). Furthermore, the complexes can obviously inhibit the migration and invasion of the quiz tumor cells, as well as inhibit the angiogenesis of HUVEC cells.

Synthesis and X-ray Crystal Structure Analysis of Substituted 1,2,4-Triazolo [4’,3’:2,3]pyridazino[4,5-b]indole and Its Precursor

The hit compound 1,2,4-triazolo[4’,3’:2,3]pyridazino[4,5-b]indole 3 was synthesized from the reflux of 4-amino-5-indolyl-1,2,4-triazole-3-thione 1 with 4′-bromoacetophenone 2 in methanol catalyzed by concentrated HCl and the desired final molecule was obtained by recrystallization from methanol. The suggested structures of compounds 1 and 3 based on the spectral characterizations were confirmed by X-ray single crystal diffraction analysis. Compound 3 crystallized in the triclinic crystal system and P-1 space group with a = 5.9308(2) Å, b = 10.9695(3) Å, c = 14.7966(4) Å, α = 100.5010(10)°, β = 98.6180(10)°, and γ = 103.8180(10)°. On the other hand, the crystal system of 1 is monoclinic, where a = 6.23510(10) Å, b = 26.0156(4) Å, c = 12.4864(2) Å, β = 93.243(2)° and the space group is P21. The triazole and indole rings are found twisted from each other in both compounds. The twist angle is higher in 3 (12.65°) than 1 (4.94–7.22°). In the case of the former, the H…H (39.6%), H…C (22.0%), N…H (12.8%) and Br…H (13.2%) contacts are the most dominant while the C…C, C…H, Br…H, N…H and S…S contacts have the characteristics of strong interactions. In the latter, the C…H, N…H, S…H, S…S, and C…C contacts are the most important. In this case, the percentages of the H…H, C…H, N…H and S…H contacts are in the range of 34.9–37.4, 20.5–24.0, 12.2–13.6, 14.0–15.8, respectively. In both systems, the shape index and curvedness of surfaces confirmed the presence of π–π stacking interactions.

Palladium complexes containing NNN pincer type ligands and their activities in Suzuki-Miyaura cross coupling reaction

Five new NNN pincer-type ligands and their palladium complexes were successfully synthesised and characterised by FT-IR, 1H NMR, 13C NMR, and UV–vis analyses. TEM analysis was used to observe the morphological character of the black residues obtained from the fourth cycle of the reusability test. Furthermore, suitable crystals of the N2,N6-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamide and its palladium complex were elucidated with the X-ray single crystal diffraction method. Both the ligand and its palladium complex crystallise in a monoclinic system with space group P21/c for the H2L4 and C2/c for the palladium complex. The structure of the pincer ligand and its palladium complex were stabilised by intramolecular and intermolecular C–H⋅⋅⋅O, C–H⋅⋅⋅N, and N–H⋅⋅⋅N contacts. A Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid was used to assess the catalytic abilities of the palladium pincer complexes. All of the prepared complexes exhibited considerable catalytic activity. However, complexes 4 (Acetonitrile-N2,N6-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamidopalladium(II)) and 5 (Acetonitrile-N2,N6-bis(2-nitrophenyl)pyridine-2,6-dicarboxamidopalladium(II)) provided almost 100% conversion with nearly 100% yield in the reaction between 4-bromotoluene and phenylboronic acid. Furthermore, these active complexes catalysed the reaction of the sterically hindered and deactivated substrates (1-Bromo-4-izobutylbenzene and 2-bromo-6-methoxynaphthalene) with phenylboronic acid, and complete conversion and yields up to 100% were achieved in a short time with the 2-bromo-6-methoxynaphthalene.

A novel approach towards the synthesis of an oxazine scaffold using scandium trifluoromethanesulfonate catalysed N, O-acetal and olefin cyclisation sequence

A novel approach to [1,3]oxazin-1-ones from 1,1-disubstituted alkene and N,O-acetals through scandium trifluoromethanesulfonate as catalyst in dichloroethane at 60 °C. The structure of this product is easily accessible. This protocol merits several advantages, such as very gentle conditions, cheap starting materials, and high yields. Altogether, 22 cases were investigated, and all the products were confirmed by spectrum methods. Three compounds were performed single crystal diffraction. The diastereochemistry was also studied in several cases.

A new ternary derivative of the Laves phases in the Mg-Co-Ga system.

Crystal structures of MgCoGa, Mg0.74CoGa0.52 and Mg0.49CoGa0.15 phases from the Mg-Co-Ga system were investigated using single-crystal diffraction. These structures belong to the family of so-called Laves phases. Hexagonal MgCoGa crystallizes as a disordered phase within the MgZn2 structure type. The orthorhombic structure of Mg0.74CoGa0.52 is a distortion variant of MgZn2 and URe2 structure type, and the structural relation is demonstrated in terms of a Bärnighausen formalism group-subgroup transformation scheme. The structure of trigonal phase Mg0.49CoGa0.15 is strongly disordered, as is shown by the presence of adjacent atomic sites which cannot be occupied simultaneously. In Mg0.49CoGa0.15, two subcells (A and B) were obtained in a ratio of 9:1. Subcell A is closely related to MgZn2-type.

Acidity of Carboxylic Acid Ligands Influences the Formation of VO2(A) and VO2(B) Nanocrystals under Solvothermal Conditions.

Vanadium dioxide (VO2) can adopt many different crystal structures at ambient temperature and pressure, each with different, and often desirable, electronic, optical, and chemical properties. Understanding how to control which crystal phase forms under various reaction conditions is therefore crucial to developing VO2 for various applications. This paper describes the impact of ligand acidity on the formation of VO2 nanocrystals from the solvothermal reaction of vanadyl acetylacetonate (VO(acac)2) with stoichiometric amounts of water. Carboxylic acids examined herein favor the formation of the monoclinic VO2(B) phase over the tetragonal VO2(A) phase as the concentration of water in the reaction increases. However, the threshold concentration of water required to obtain phase-pure VO2(B) nanocrystals increases as the pKa of the carboxylic acid decreases. We also observe that increasing the concentration of VO(acac)2 or the concentration of acid while keeping the concentration of water constant favors the formation of VO2(A). Single-crystal electron diffraction measurements enable the identification of vanadyl carboxylate species formed in reactions that do not contain enough water to promote the formation of VO2. Increasing the length of the carbon chain on aliphatic carboxylic acids did not impact the phase of VO2 nanocrystals obtained but did result in a change from nanorod to nanoplatelet morphology. These results suggest that inhibiting the rate of hydrolysis of the VO(acac)2 precursor either by decreasing the ratio of water to VO(acac)2 or by increasing the fraction of water molecules that are protonated favors the formation of VO2(A) over VO2(B).

Visible-Light-Responsive 2D Photocatalysts Assembled by Evans-Showell-Type POMs and Metalloviologen Frameworks for Sulfide-Sulfoxide Transformation.

Sulfide-sulfoxide aerobic photo-oxidation is of great interest in organic and medicinal chemistry; however, developing efficient and facile heterogeneous photocatalytic systems without additional additives remains challenging. Herein, we intentionally designed and synthesized two polyoxometalate (POM)-based metalloviologen frameworks, formulated as [MII(4-PBPY)2(H2O)][MII(H2O)4][CoIII2MoVI10H4O38]·nH2O (M = Cu, n = 10 for 1; M = Co, n = 11 for 2), prepared by the mild one-step synthesis strategy and characterized in detail. X-ray single-crystal diffraction analysis shows that they present a two-dimensional layered structure formed by two parallel metalloviologen layers pillared by dimeric Evans-Showell-type POMs. The connection of POM to the metalloviologen framework enables easier flow of electrons to the POM port, which can theoretically further induce O2 to generate reactive oxygen species (O2•-) to oxidize substrates to form target products. As expected, both 1 and 2 exhibit outstanding photocatalytic activity in the oxidation of sulfides. Within 6 h, methyl phenyl sulfide can be quantitatively converted into methyl phenyl sulfoxide. The in-depth mechanism reveals that there is also a synergistic energy-transfer pathway in the catalytic system in addition to the electron-transfer pathway. In addition, the corresponding catalytic activity and structure can be well maintained after at least 10 cycle experiments.

Synthesis and Characterization of Iron Bispyridine Bisdicyanamide, Fe[C5H5N]2[N(CN)2

Fe[C5H5N]2[N(CN)2]2 (1) was synthesized from a reaction of stoichiometric amounts of NaN(CN)2 and FeCl2·4H2O in a methanol/pyridine solution. Single-crystal and powder diffraction show that 1 crystallizes in the monoclinic space group I2/m (no. 12), different from Mn[C5H5N]2[N(CN)2]2 (P21/c, no. 14) due to tilted pyridine rings, with a = 7.453(7) Å, b = 13.167(13) Å, c = 8.522(6) Å, β = 114.98(6)° and Z = 2. ATR-IR, AAS, and CHN measurements confirm the presence of dicyanamide and pyridine. Thermogravimetric analysis shows that π-stacking interactions of the pyridine rings play an important role in structural stabilization. Based on DFT-optimized structures, a chemical bonding analysis was performed using a local-orbital framework by projection from a plane-wave basis. The resulting bond orders and atomic charges are in good agreement with the expectations based on the structure analysis. SQUID magnetic susceptibility measurements show a high-spin state FeII compound with predominantly antiferromagnetic exchange interactions at lower temperatures.

Magnetic ground state and perturbations of the distorted kagome Ising metal TmAgGe

Magnetic order and excitations of the distorted kagome intermetallic magnet TmAgGe are explored using a variety of methods, including single-crystal neutron diffraction, inelastic neutron scattering, Monte Carlo simulations, and the random phase approximation. The magnetic properties are governed by strong, local single-ion anisotropy and geometrically frustrated magnetic exchanges. The authors establish multi-k structures at several different magnetic field configurations and model effective exchange parameters using field-dependencies of the magnetic neutron diffraction reflections and the weakly dispersive crystal electric field mode.

Synthesis, Hirshfeld atom refinement of crystal structure, and Hirshfeld surface analysis of 5-ethoxycarbonyl-6-methyl-4-(2-(trifluoromethyl)phenyl)-3,4-dihydropyrimidin-2-(1H)-one formic acid monosolvate

We report the cyanamide-based multicomponent synthesis and crystal structure of the title compound, 5-ethoxycarbonyl-6-methyl-4-(2-(trifluoromethyl)phenyl)-3,4-dihydropyrimidin-2-(1H)-one which crystallized as a binary cocrystal with formic acid, C15H15F3N2O3·HCO2H (DHPM···FA). The molecular structure of the DHPM···FA heterosynthon was unequivocally confirmed using X-ray single crystal diffraction techniques and spectroscopic methods. X-ray diffraction analysis shows that this cocrystalline material crystallizes in the monoclinic space group P21/n, Z = 4 with the 3,4-dihydropyrimidin-2-(1H)-one ring in a twist-boat form attached to the ester and phenyl group in an s−cis/s−cis and sp−conformation, respectively. The molecular structure and crystalline packing are stabilized by intermolecular N2–H2∙∙∙O1, N1–H1∙∙∙O5, O4–H4A∙∙∙O1, C4–H4∙∙∙O5, C6–H6∙∙∙O3 and C16–H16∙∙∙O3 hydrogen bonds into a 3D supramolecular network R22(8). Furthermore, the Hirshfeld surface analysis confirms that the most important contributions for the crystal packing are the H∙∙∙O/O∙∙∙H (58.7%), C − H···C (17.8%), H∙∙∙H (30.4%) and H∙∙∙F/F∙∙∙H (18.3%) surface contacts.

Field-induced partial disorder in a Shastry-Sutherland lattice

A 2-Q antiferromagnetic order of the ferromagnetic dimers was found below TN = 2.9 K in the Shastry-Sutherland lattice BaNd2ZnS5 by single crystal neutron diffraction. The magnetic order can be understood by the orthogonal arrangement of local Ising Nd spins, identified by polarized neutrons. A field was applied along [1 -1 0] to probe the observed metamagnetic transition in the magnetization measurement. The field decouples two magnetic sublattices corresponding to the propagation vectors q1 = (½, ½, 0) and q2 = (−½, ½, 0), respectively. Each sublattice shows a “stripe” order with a Néel-type arrangement in each single layer. The “stripe” order with q1 remains nearly intact up to 6 T, while the other one with q2 is suppressed at a critical field Hc ~1.7 T, indicating a partial disorder. The Hc varies with temperature and is manifested in the H-T phase diagram constructed by measuring the magnetization in BaNd2ZnS5.

Cytotoxic pyridine alkaloids from a marine-derived fungus Arthrinium arundinis exhibiting apoptosis-inducing activities against small cell lung cancer

Small cell lung cancer (SCLC) is a kind of high-grade neuroendocrine carcinoma, which is characterized by a higher proliferative rate, earlier metastasis and more poor outcomes compared to non-small cell lung cancer (NSCLC). Under the guidance of MS/MS based molecular networking, three undescribed pyridone alkaloids, namely, arthpyrones M–O (1–3), together with two known pyridone derivatives, arthpyrones C (4) and G (5), were isolated from a sponge-derived Arthrinium arundinis. Their structures were determined through extensive spectroscopic analysis, ECD calculations, and X-ray single-crystal diffraction. Arthpyrone M (1) possessed a novel cage structure bearing an ether bridge functionality rarely reported in this class of metabolites. All isolated compounds were evaluated for their cytotoxicities against five cancer cell lines. As a result, compounds 1–5 showed cytotoxicity against some or all of the five cancer cell lines with IC50 values ranging from 0.26 to 6.43 μM. Among them, arthpyrone O (3) not only exhibited potent efficacy against the proliferative activity of SCLC cells and induced apoptosis in vitro, but also significantly inhibited the growth of xenograft tumor based on SCLC cells in vivo, which indicated 4-hydroxy-2-pyridone alkaloids might been revised as privileged scaffolds in drug discovery.

Synthesis of N-acylated pyrazolines: Spectroscopic, crystallographic, Hirshfeld Surface, lead sensing and theoretical studies

N-Acylated-2-pyrazolines (NA2Pyr) were synthesized from chalcone and hydrazine hydrate under one pot cyclocondensation in the presence of propionic acid and trifluoroacetic acid respectively. The structures were determined using FT-IR, 1H NMR, 13C NMR spectral analyses, as well as single crystal diffraction study (Sc-XRD). An effective metal ion sensor (Lead ion) with a flat glassy carbon electrode (GCE) was produced for prospective use by coupling a conducting coating binder (PEDOT:PSS) with a thin-layer NA2Pyr modified electrode (NA2Pyr/GCE). Linear sweep voltammetry was used to detect lead (Pb2+) ions in phosphate aqueous phase. The sensitivity (11,867 uAnM−1cm−2) of the chemical sensor probe was measured utilizing the calibration curve slope and the adjusted electrode active surface area. The linear dynamic range (LDR: 0.01 nM to 10.0 mM) was computed using the calibration plot's maximal linearity line. The detection limit (0.008 nM) was calculated by including 3σ/m (where σ is the standard deviation of the blank response and m is the slope of the calibration curve). The novel electrochemical method is dependable and effective technique for detecting heavy metal ions as a selective lead-sensor for the protection of large-scale medical, biochemical, and environmental fields. Density functional theory (TD-DFT/B3LYP/6-311++G(d,p) was used to computed FMO computations and further study using the optimized geometric parameters of the ground state molecules. According to the predicted energies for HOMO and LUMO, in which the charge of molecule is conveyed, and MEP map, the chemically reactive zone suitable for drug action was identified. The Electron Localization Function (ELF), Non-Bonding Orbitals, Excitation Energies, AIM Charges, and Fukui Functions are also calculated. The docking study contributed to the analysis of EGFR protein binding.

High-pressure single-crystal diffraction at the Australian Synchrotron.

A new high-pressure single-crystal diffraction setup has been designed and implemented at the Australian Synchrotron for collecting molecular and protein crystal structures. The setup incorporates a modified micro-Merrill-Bassett cell and holder designed specifically to fit onto the horizontal air-bearing goniometer, allowing high-pressure diffraction measurements to be collected with little to no modification of the beamline setup compared with ambient data collections. Compression data for the amino acid, L-threonine, and the protein, hen egg-white lysozyme, were collected, showcasing the capabilities of the setup.

Two Purely Inorganic Cationic Tellurite Materials Based on Group IB Metal Tetrafluoroborates with Similar Lamellar Cationic Layers: [Cu2F(Te2O5)](BF4) and [Ag18O2(Te4O9)4(Te3O8)(BF4)2]·2HBF4.

Two new purely inorganic cationic tellurite networks of Group IB metal-based tetrafluoroborates, namely, [Cu2F(Te2O5)](BF4), 1, and [Ag18O2(Te4O9)4(Te3O8)(BF4)2]·2HBF4, 2, have been hydrothermally synthesized under mild conditions. The prepared materials have been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR and Raman spectroscopy, SEM-energy-dispersive spectroscopy, UV-vis-NIR diffuse reflectance, magnetic study, and TG analyses. Single-crystal diffraction studies show that both materials have similar cationic Cu/Ag tellurite layers with tetrafluoroborates as interlamellar charge-balancing anions. Magnetic results indicate that [Cu2F(Te2O5)](BF4), 1, exhibits a mainly short-range antiferromagnetic ordering within the 2D layer, and further detailed analysis of magnetic susceptibility analysis confirms a spin-singlet ground state with an energy gap of 85 K.

Two New Compounds Based on Bi-Capped Keggin Polyoxoanions and Cu-Bpy Cations Contain Both CuII and CuI Complexes: Synthesis, Characterization and Properties.

Two inorganic-organic hybrid complexes based on bi-capped Keggin-type cluster, {([CuII(2,2'-bpy)2]2[PMoVI8VV2VIV2O40(VIVO)2])[CuI(2,2'-bpy)]}∙2H2O (1) and {[CuII(2,2'-bpy)2]2[SiMoVI8.5MoV2.5VIVO40(VIVO)2]}[CuI0.5(2,2'-bpy)(H2O)0.5] (2) (bpy = bipyridine), had been hydrothermally synthesized and structurally characterized by elemental analysis, FT-IR, TGA, PXRD and X-ray single-crystal diffraction analysis. Compound 1 consists of a novel 1-D chain structure constructed from [CuI(2,2'-bpy)]+ unit linking bi-supported POMs anion {[CuII(2,2'-bpy)2]2[PMoVI8VV2VIV2O40(VIVO)2]}-. Compound 2 is a bi-capped Keggin cluster bi-supported Cu-bpy complex. The main highlights of the two compounds are that Cu-bpy cations contain both CuI and CuII complexes. Furthermore, the fluorescence properties, the catalytic properties, and the photocatalytic performance of compounds 1 and 2 have been assessed, and the results show that both compounds are active for styrene epoxidation and degradation and adsorption of Methylene blue (MB), Rhodamine B (RhB) and mixed aqueous solutions.