X-ray Crystallography Diffraction Research Articles

Biogenic mediated green synthesis of NiO nanoparticles for adsorptive removal of lead from aqueous solution

The spread of heavy metal in water bodies, particularly lead (Pb), has occurred as a global threat to human existence. In this study, NiO nanoparticles (NPs) was prepared by coprecipitation approach using Hagenia abyssinica plant extract mediated as a reducing and template agent for the removal of Pb from aqueous solution. X-ray crystallographic diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and Brunauer-Emmett-Teller (BET) techniques were employed for the characterization of as prepared NiO NPs. The efficacy of adsorbent was evaluated on the removal of Pb2+ by varying the adsorptive parameters such as pH, Bio-NiO amount, interaction time, and Pb2+ concentration. The adsorption was 99.99% at pH, 0.06 g of NiO NPs dose, 60 mg L−1 concentrations of Pb2+ within 80 min contact time. The higher removal efficiency is could be due to higher surface area (151 m2g-1). The adsorption process was best fitted with Freundlich isotherm and pseudo-second order kinetic models, implying that it was chemical adsorption on the heterogeneous surface. The adsorption intensity (n) was found to be 1/n < 1 (0.47) indicating adsorption of Pb2+ on the surface of Bio-NiO NPs was favorable with a maximum adsorption capacity 60.13 mg g−1. The reusability studies confirmed that the synthesized bio-NiO NPs were an effective adsorbent for removing Pb2+ from aqueous solution up to five cycles.

Investigating the antimicrobial potential of diorganotin(IV) complexes incorporating hydrazone ligands: Synthesis, structural elucidation, X-ray crystallography, DFT, and antimicrobial activity

Sixteen diorganotin(IV) complexes having the general formula R2SnL1-4, (where R = Me, Et, Bu, and Ph) have been synthesized from hydrazone ligands, which were obtained by the condensation reaction of 4-(benzyloxy)-2-hydroxybenzaldehyde with hydrazide derivatives. The synthesized compounds were fully characterized by several spectroscopic and physicochemical techniques, like elemental analysis, FT-IR, (1H, 13C, and 119Sn) NMR, mass spectrometry, UV–Vis. and TGA. The obtained spectroscopic data revealed that hydrazone ligand bound to the tin atom in a tridentate fashion via phenolic O, imine N, and enolic O donor atoms and forms a pentacoordinated environment which was further confirmed by the X-ray crystallography diffraction analysis of complex 4. Complex 4 crystallizes in triclinic cell with space group P-1 and exhibits a distorted trigonal bipyramidal geometry. The equilibrium geometry of selected compounds was estimated using density functional theory (DFT) calculations implemented at B3LYP/LanL2DZ theory level to get insight into geometric and electronic structures using Gaussian 9 software package. Furthermore, the synthesized compounds were tested for their in vitro antimicrobial activity against four bacterial and two fungal strains. The results demonstrated that diorganotin(IV) complexes displayed better activity as compared to the hydrazone ligands. The best results are shown by complexes 4, 8, 12 and 16 with MIC values in the range of 0.0048–0.0050 µmol/mL, respectively against B. subtilis and C albicans strains, further suggesting their greater lipophilicity which may have a substantial impact on facilitating microbial cell penetration.

Dual-nodes bridged cobalt-modified Keggin-type polyoxometalate-based chains for highly efficient CO2 photoconversion.

The design of efficient catalysts for photocatalytic CO2 conversion is of great importance for the sustainable development of society. Herein, three polyoxometalate (POM)-based crystalline materials were formulated prepared by substituting transition metals and adjusting solvent acidity with 2-(2-pyridyl) benzimidazole (pyim) as the light-trapping ligand, namely {[SiW12O40][Co(pyim)2]2}·2C2H5OH (SiW12Co2), {[SiW12O40][Ni(pyim)2]2}·2C2H5OH (SiW12Ni2), and {[SiW12O40][Mn(pyim)2]2}·2C2H5OH (SiW12Mn2). X-ray crystallography diffraction analysis indicates that the three complexes exhibit isostructural properties, and form a stable one-dimensional chain structure stabilized by two [M(pyim)2]22+ (M = Co, Ni, and Mn) fragments serving as dual-nodes to the adjacent SiW12 units. A comprehensive analysis of the structural characterization and photocatalytic CO2 reduction properties is presented. Under light irradiation, SiW12Co2 exhibited a remarkable CO generation rate of 10 733 μmol g-1 h-1 with a turnover number of 328, outperforming most of the reported heterogeneous POM-based photocatalysts. Besides, cycling tests revealed that SiW12Co2 is an efficient and stable photocatalyst with great recyclability for at least four successive runs. This study proves that the successful incorporation of diverse transition metals into the POM anion could facilitate the development of highly efficient photocatalysts for the CO2RR.

Limonoids from the Branches and Leaves of Aglaia lawii and Their Cytotoxic Activities.

Three undescribed limonoids (1-3), named aglaians G-I, and one new natural product azedaralide (4), together with nine known analogues (5-13) were isolated from the branches and leaves of Aglaia lawii by RP C18 column, silica gel column, Sephadex LH-20 column chromatography and preparative HPLC. The structures of the new compounds were elucidated by IR, HRESIMS, 1D, 2D NMR, electronic circular dichroism (ECD) calculations and X-ray crystallography diffraction analysis. The results of bioassay showed that the compound 12 exhibited potential inhibitory activity against six human tumor cell lines (MDA-MB-231, MCF-7, Ln-cap, A549, HeLa and HepG-2) with IC50 values as 8.0-18.6 μM.

In Vitro Insight on Antifungal-Specific Potentiality of Ni(II) Complex against Colletotrichum siamense and Fusarium equisetum Phytopathogens.

In an initiation to investigate a prospective bioactive compound, a mononuclear Ni(II) complex with N, N, and O donor Schiff base ligand was synthesized and characterized in the present study through FTIR, ESI-mass, and X-ray crystallographic diffraction studies. A slightly distorted octahedral geometry has been obtained for the Ni(II) complex from X-ray crystallographic diffraction studies. In vitro comprehensive biological studies show the antifungal specific efficiency of the complex against Colletotrichum siamense (AP1) and Fusarium equisetum (F.E.) pathogens, which are responsible for anthracnose and wilt disease, respectively, but no inhibitory effect on both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) for these pathogens was observed to be 0.25 and 0.5 mM, respectively. The experiment also reveals that significant damage of mycelia and enlarged, misshaped damaged spores are noticed in comparison to hexaconazole, used as a positive control under a light microscope post 48 h treatment of AP1 and F.E. with the MIC of the complex. The binding interaction studies of the complex with DNA and BSA performed through a variety of spectroscopic techniques demonstrate a strong binding behavior of the complex for both the binding systems. The observed negative ΔH° and ΔS° values for DNA reveal the existence of hydrogen-bonding/van der Waals interactions for DNA which was also exemplified from the molecular docking and self-assembly studies of the complex. The positive ΔH° and ΔS° values for BSA demonstrate the hydrophobic interactions of the complex with BSA. However, cytotoxicity studies against the MDA-MB-231 breast cancer cell line did not demonstrate any significant potentiality of the complex as an anticancer agent. All the bio-experimental studies provide clear evidence that the synthesized Ni(II) complex exhibits potential antifungal activity and could be used as a therapeutic fungicide agent in comparison to hexaconazole in agricultural practices.

Isoselective Polymerization of rac-Lactide by Magnesium Initiators Bearing Achiral Di(2-pyridyl)methyl Substituted Aminophenolate Ligands.

Reactions of achiral di(2-pyridyl)methyl substituted aminophenols L1-6H (2-{N-R3-N-[di(2-pyridyl)methyl]aminomethyl}-4-R1-6-R2-C6H2OH: R1 = R2 = tBu, R3 = nBu (L1H), R3 = nhexyl (L2H), R3 = cyclohexyl (L3H); R1 = R2 = cumyl, R3 = nBu (L4H), R3 = nhexyl (L5H), R3 = cyclohexyl (L6H)) with {Mg[N(SiMe3)2]2}2 ([L1-6H]:[Mg] = 1:1) afforded a series of magnesium silylamido complexes 1-6. In the solid state, the magnesium center of 3, 4, and 6 is penta-coordinated by the tetradentate aminophenloate ligand and one silylamido ligand to form a seriously distorted square-pyramidal geometry as confirmed by X-ray crystallography diffraction analysis. VT 1H NMR and ROESY experiments further indicate that these magnesium complexes are also five-coordinated in solutions where the coordination of either of the two pyridyl pendants to the magnesium center is maintained. Complexes 1-6 are highly active toward the ring-opening polymerization of rac-lactide (rac-LA) at r.t. both in toluene and in tetrahydrofuran, capable of polymerizing 500 equiv of monomer to high conversions just within minutes. Among them, complex 3 exhibited the highest iso-stereoselectivity, affording moderately isotactic polylactide in toluene (Pm = 0.75). It is found that the isoselectivities and activities of these magnesium complexes toward the polymerization of rac-LA are closely associated with the substituents at the ortho-position of the phenoxide unit and on the skeleton nitrogen atom of the ligand. On the basis of NMR spectroscopic studies, the formation of isotactic PLAs with dominant stereoblock sequences was witnessed by using these magnesium complexes as initiators, and the inequivalent coordination of two pyridyl pendant arms in these magnesium complexes might be the source of exerting isoselective control.

Cost-effective measurement of magnetostriction in nanoscale thin films through an optical cantilever displacement method

A cost-effective method for the quantitative characterization of the magnetostrictive effect in thin films is presented. In this method, a sample's magnetostriction is extrapolated from the tip displacement of a thin-film magnetostrictive cantilever. The tip displacement is measured by monitoring the position of a reflected laser beam using two differentially coupled photodiode positioning sensors. In contrast with alternative optical deflection-angle devices designed for educational purposes, the detection limit of our setup resolves submicron-level displacements from nanoscale thin films. The efficacy of the system is demonstrated through measurements using amorphous 200-nm thick Terfenol-D/Si (100) bimorph cantilevers. In these measurements, magnetostriction values of 106 ± 3.5 ppm at ±4300 Oe applied field were attained, where the voltage noise floor was ±0.05 V (a cantilever displacement uncertainty of ±70 nm). In-plane (IP) and out-of-plane (OOP) magnetization curves and crystallographic x-ray diffraction (XRD) were performed to determine the magnetic behavior and confirm the amorphous nature of the films, respectively. The experimental methods and material characterization systems demonstrated here enhance the understanding of complex magnetic phenomena and introduce common measurement techniques to better equip students with the skills for insightful analysis of fundamental magnetic physics.

New neo-clerodane diterpenes from Teucrium polium subsp. capitatum

Phytochemical investigation of a methanolic extract from the aerial parts of Teucrium polium subsp. capitatum afforded six acetoxylated neo-clerodane diterpenes, including 20-acetylauropolin and 6-acetylteucjaponin A, along with four previously undescribed congeners. The compounds were isolated by a combination of silica gel column chromatography and preparative HPLC-ESIMS. Their structures were determined by extensive NMR analysis, HRESIMS, and by comparison with literature data of related compounds. The absolute configuration of 20-acetylauropolin was confirmed by X-ray crystallographic diffraction analysis. Some of the isolated diterpenes possess structural features unusual in the class of neo-clerodane diterpenes, such as a rare C-20 hemiacetal function which forms an oxepane ring to C-7 of the trans-decalin core structure.

Eremophilane-type and xanthanolide-type sesquiterpenes from the aerial parts of Xanthium sibiricum and their anti-inflammatory activities

The traditional Chinese medicine Xanthium sibiricum Patrin ex Widder is used to treat wind-cold headache, nasal congestion, nasal discharge, allergic rhinitis, sinusitis, urticaria, and arthritis. Our previous studies found that sesquiterpene lactones, the main bioactive constituents of X. sibiricum, relieved airway inflammation in an asthma mouse model. To obtain active sesquiterpenes, five undescribed ones, including a pair of eremophilanes and three xanthanolides, together with eight known xanthanolides were isolated from X. sibiricum. Their structures were identified by IR, UV, HR-ESI-MS and NMR spectroscopic data, and their absolute configurations were determined by X-ray crystallographic diffraction analysis and the comparison between their experimental and calculated electronic circular dichroism. All isolated compounds were evaluated for their inhibitory effects on nitric oxide production, and Tnf-α, Il-1β, and Il-6 mRNA expression induced by lipopolysaccharide in the macrophage cell line RAW264.7. Further investigation showed that xanthsibiriolide and 11β-hydroxyl-13-chloro-8-epi-xanthatin exerted their anti-inflammatory effects by inhibiting the PI3K/AKT/mTOR signaling pathway. Analysis of the structure-activity relationships indicated that the α,β-unsaturated lactone ring and the 1,5-epoxide group might be the bioactive groups of xanthanolides, and these results provide a basis for further exploration of sesquiterpene-type lead compounds with anti-inflammatory activity.

Bioactive Monoterpenes and Polyketides from the Ascidian-Derived Fungus Diaporthe sp. SYSU-MS4722.

There has been a tremendous increase in the rate of new terpenoids from marine-derived fungi being discovered, while new monoterpenes were rarely isolated from marine-derived fungi in the past two decades. Three new monoterpenes, diaporterpenes A–C (1–3), and one new α-pyrones, diaporpyrone A (6), along with nine known polyketides 4, 5, and 7–13 were isolated from the ascidian-derived fungus Diaporthe sp. SYSU-MS4722. Their planar structures were elucidated based on extensive spectroscopic analyses (1D and 2D NMR and HR-ESIMS). The absolute configurations of 1 and 3 were identified by an X-ray crystallographic diffraction experiment using Cu-Ka radiation, and those of compound 2 were assigned by calculating NMR chemical shifts and ECD spectra. It afforded an example of natural epimers with different physical properties, especially crystallization, due to the difference in intermolecular hydrogen bonding. Compounds 9, 10, and 13 showed moderate total antioxidant capacity (0.82 of 9; 0.70 of 10; 0.48 of 13) with Trolox (total antioxidant capacity: 1.0) as a positive control, and compounds 5 and 7 showed anti-inflammatory activity with IC50 values of 35.4 and 40.8 µM, respectively (positive control indomethacin: IC50 = 35.8 µM).

Involucrasin C, Anti-Inflammatory 2,3-Dihydro-1H-Indene Derivative from Chinese Dai Ethnic Medicine Shuteria involucrata.

(±)-Involucrasin C (1), a pair of new 2,3-dihydro-1H-indene enantiomers, along with an enantiomeric analog (2), were isolated from Shuteria involucrata. Their structures were established by the basis of comprehensive spectroscopic data analysis and X-ray crystallographic diffraction. Both 1 and 2 significantly inhibited the secretion of pro-inflammatory cytokines IL-6, TNF-α, and IL-1β, suggesting that these two natural 2,3-dihydro-1H-indene derivatives may be active components of S. involucrata and may block inflammation in the initial stage.

2-Substituted perimidines: Zwitterionic tauterism in solid state, substituent effect on their crystal packing and biological activity

Structural and electronic properties of five 2-substituted 1H-perimidines: 3-(1H-perimidin-2-yl)propanoic acid (SPm), (Z)-3-(1H-perimidin-2-yl)acrylic acid) (MPm), (Z)-3-(1H-perimidin-2-yl)but-2-enoic acid (CPm-1), (Z)-2-methyl-3-(1H-perimidin-2-yl)acrylic acid (CPm-2) and 2-((1H-perimidin-2-yl)methyl)acrylic acid (IPm) have been studied. All perimidines bear aliphatic acidic substituents at 2-position andare distinguished by a carbon-carbon double bond in the substituents. The crystallographic X-ray diffraction analysis revealed that they exist in the solid state as zwitterions. Primary screening of 2-substituted 1H-perimidines against different cancer cell lines were also realized. The results obtained are discussed in terms of the structure-property relationships and compared with density functional theory calculations. Additionally, the effect of inclusion of water molecules in the crystal lattice on the molecular packing is analyzed.

Synthesis, in vitro and in silico antitumor evaluation of 3-(2,6-dichlorophenyl)-1,5-diphenylpentane-1,5‑dione: Structure, spectroscopic, RDG, Hirshfeld and DFT based analyses

New bischalcone derivative 3-(2,6-dichlorophenyl)-1,5-diphenylpentane-1,5‑dione (C23H18Cl2O2) has been efficiently synthesized and the solid state formation of the grown crystals was characterized by X-ray crystallographic diffraction (XRD)analysis at 296 K. The single crystal XRD results show that the title compound belongs to triclinic system with unit cell dimensions, a = 9.4104 (12) (Å), b = 10.2951(13) (Å), c = 10.9411(15) (Å) and V = 980.9(Å3). The key contributor intermolecular interactions C‒O···H/H···O‒C were explored by Hirshfeld surface analysis. The active functional group interpretations have been carried using FT-IR and FT-Raman spectroscopies with the assistance of energy distributions. Density functional theory (DFT) calculations of the synthesized compound carried out for better understanding of molecular futures. Hyperconjugative interactions present in the molecule were also quantified using natural bond orbitals (NBO). Reactivity and stability of the title molecule assessed utilizing global reactivity descriptors. The condensed Fukui functions explored the available electrophile and nucleophile regions in the form of local based descriptors. The reduced density gradient (RDG) isosurfaces reveals the dominance of non-bonded interactions of the title compound. MTT assay revealed that the title compound had potentiate antitumor activity against human lung cancer A549 cells with 40.71 µg/mL IC50 value. Moreover the capability of the compound to be interconnected within the key amino acids of lung cancer receptor binding sites was detected by molecular docking. Antibacterial and antifungal efficacy of the title compound studied using Kirby-Bauer disc diffusion technique.

Two novel macrocyclic organotin (IV) carboxylates based on bipyrazoledicarboxylic acid derivatives: Syntheses, crystal structures and antifungal activities

Two new organotin (IV) bipyrazole-dicarboxylate macrocyclic complexes, C1 (C58H100N8O10Sn4) and C2 (C58H100N8O12Sn4, 4 H2O), are synthesized by reaction of the bipyrazole-dicarboxylic acids L1 = 1,1′-(propane-1,3-diyl)bis(5-methyl-1H-pyrazole-3-carboxylic acid) and L2 = 1,1′-(2-hydroxypropane-1,3-diyl)bis(5-methyl-1H-pyrazole-3-carboxylic acid) with oxide di-(n-butyl)tin. The structure of these complexes is characterized using NMR, IR and UV-visible spectroscopies as well as single crystal X-ray diffraction. Compound C1 crystallizes within the triclinic symmetry in space group P1¯ with a = 12.9410(5), b = 13.6143(5), c = 22.7675(8) Å, α = 92.981(1), β = 91.180(1), γ = 116.966(1) °, while C2 crystallizes within the rhombohedral symmetry in space group R3 with a = b = 29.4419(5), c = 23.0326(5) Å, α = β = 90 and γ = 120 °. The analysis by X-ray crystallography diffraction reveals that both complexes are centrosymmetric macrocycles and contain a tetra-nuclear four-fold ladder-like organo-oxotin cluster. Two Sn atoms are found to be five-coordinated while the two others are four-coordinated. The antifungal activity of these metal-cyclic compounds C1 and C2 is examined and compared to that of the corresponding ligands against the pathogenic strain Fusarium oxysporum f. sp. albedinis. The complexes C1 and C2 possess an interesting fungicidal power even higher than the ligands L1 and L2.

Twisted Intramolecular Charge Transfer—Aggregation-Induced Emission Fluorogen with Polymer Encapsulation-Enhanced Near-Infrared Emission for Bioimaging

Fluorescence probes with strong near-infrared (NIR) emission and water solubility are considered useful visualization tools for localization marking as well as investigating cell migration and tran...

A brief history of modern crystallography and how taking risks run in the family

The history of X-ray crystallography and X-ray diffraction, and their important contributions to science as a whole, is profound. From the first images of Wilhelm Roentgen and Madame Curie taking a...

Asymmetric Spirocyclization Enabled by Iridium and Brønsted Acid-Catalyzed Formal Reductive Cycloaddition

A catalytic, enantioselective spirocyclization of formanilides or formylindolines and enamides has been developed herein. The reaction proceeds through a sequential iridium-catalyzed hydrosilylatio...

Synergistic Antitumor Effect of 5-Fluorouracil Combined with Constituents from Pleurospermum lindleyanum in Hepatocellular Carcinoma SMMC-7721 Cells.

A Chinese folk medicine plant Pleurospermum lindleyanum possesses pharmacological activities of heat-clearing, detoxifying and preventing from hepatopathy, coronary heart disease, hypertension, and high altitude sickness. We isolated and characterized its constituents to investigate its synergistic effects against human hepatoma SMMC-7721 cells. The aim of this study was to explore the synergistic anti-cancer activities of isolates from P. lindleyanum with 5-FU on hepatoma SMMC-7721 cells in vitro and their primary mechanisms. Sequential chromatographic techniques were conducted for the isolation studies. The isolate's structures were established by spectroscopic analysis as well as X-ray crystallographic diffraction. Growth inhibition was detected by MTT assay. The isobologram method was used to assess the effect of drug combinations. Flow cytometry and western blot were used to examine apoptosis and protein expression. A new coumarin (16), along with sixteen known compounds, were isolated from the whole plant of P. lindleyanum and their structures were elucidated by spectroscopic methods. Four coumarins (2, 3, 5, and 16), two flavonoids (8 and 9) and three phytosterols and triterpenes (12-14) were found to synergistically enhance the inhibitory effect of 5-FU against SMMC-7721 cells. Among them, compounds 3 and 16 exhibited the best synergistic effects with IC50 of 5-FU reduced by 16-fold and 22-fold possessing the minimum Combination Index (CI) 0.34 and 0.27. The mechanism of action of combinations might be through synergistic arresting for the cell cycle at G1 phases and the induction of apoptosis. Moreover, western blotting and molecular docking revealed that compounds 3 or 5 might promote 5-FU-induced apoptosis by regulating the expression of Caspase 9 and PARP. Constituents from P. lindleyanum may improve the treatment effectiveness of 5-FU against hepatocellular carcinoma cells.

A 24-membered macrocyclic triorganotin(IV) carboxylate: Synthesis, characterization, crystal structure, and antitumor activity

A novel organotin carboxylate based on an amide carboxylic acid, (Ph3Sn)6(L)6 (complex 1) (L = 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)acetic acid), was designed and synthesized. The complex was characterized using elemental analysis, IR spectroscopy, and 1H, 13C, and 119Sn NMR spectroscopy. X-ray crystallography diffraction analysis revealed that the complex is a hexanuclear triphenyltin carboxylate macrocycle. Each bridging ligand of the macrocycle coordinates with two Sn atoms. Intermolecular π···π interactions link the complex into a complicated supramolecular structure, which is discussed in detail. The fluorescence and antitumor activities of complex 1 were also studied.

Antibacterial harziane diterpenoids from a fungal symbiont Trichoderma atroviride isolated from Colquhounia coccinea var. mollis

Fungal endophytes from plants are an important source for discovery of novel bioactive natural products. In this study, five undescribed harziane diterpenoids with a 4/7/5/6 tetracyclic scaffold, harzianols F‒J and three known derivatives, were obtained from the liquid fermentation of an endophytic fungus Trichoderma atroviride B7, which was isolated from the healthy flower of a Lamiaceae plant Colquhounia coccinea var. mollis. Their structures were elucidated by comprehensive spectroscopic analyses and X-ray crystallographic diffraction in the case of harzianol F. Harzianol I exhibited significant antibacterial effect against the growth of Staphylococcus aureus (EC50 = 7.7 ± 0.8 μg/mL), Bacillus subtilis (EC50 = 7.7 ± 1.0 μg/mL), and Micrococcus luteus (EC50 = 9.9 ± 1.5 μg/mL). Meanwhile, cytotoxic activity of harzianol I against three cancer cell lines was also observed. A plausible biosynthetic pathway for harziane diterpenoids was proposed.