Single-crystal Diffractometry Research Articles

Piperine-hydroxybenzoate as phytochemistry antiosteoarthritis combination: Structural, solubility, and in vivo antiinflammatory study

This study discusses the composition and structure determination of a new multicomponent system from antiinflammatory natural ingredients, consisting of piperine (Pip) and 4-hydroxybenzoic acid (HBA), named Pip-HBA. In addition, this research studied its solubility and anti-inflammatory activity. After screening the stoichiometric proportions, this multicomponent system formation reaction was carried out using the solvent-dropped grinding and evaporation methods. Characterizations using solid analysis including differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), and Fourier transform infrared spectroscopy (FTIR), confirmed the formation of Pip-HBA. These multicomponent systems showed different thermograms and diffractograms. Furthermore, the FTIR spectrum of Pip-HBA multicomponent system differs from the physical mixture and its constituent components. Single crystal diffractometry (SCXRD) determined Pip-HBA to be a new multicomponent system structure in three dimensions. Pip-HBA showed increased solubility and anti-inflammatory activity compared to single piperine. Therefore, Pip-HBA multicomponent system has quite potential for further preparation development.

Iron(III)-Complexes with N-Phenylpyrazole-Based Ligands

The use of iron as a replacement for noble metals in photochemical and photophysical applications is challenging due to the typically fast deactivation of short-lived catalytically active states. Recent success of a cyclometalated iron(III) complex utilizing a bis-tridentate ligand motif inspired the use of phenyl-1H-pyrazole as a bidentate ligand. Five complexes using the tris(1-phenylpyrazolato-N,C2)iron(III) complex scaffold are presented. In addition to the parent complex, four derivatives with functionalization in the meta-position of the phenyl ring are thoroughly investigated by single crystal diffractometry, UV-Vis-spectroscopy, and cyclic voltammetry. Advanced X-ray spectroscopy in the form of X-ray absorption and emission spectroscopy allows unique insights into the electronic structure as well as DFT calculations. The ligand design leads to overlapping MLCT and LMCT absorption bands, and emissive behavior is suppressed by low-lying MC states.

ПОИСК И СИНТЕЗ НОВЫХ ФТОРСОДЕРЖАЩИХ БОРАТОВ ОДНО- И ДВУХВАЛЕНТНЫХ МЕТАЛЛОВ

By evaporating the solution, crystals of two new fluoroborates, M(BF4)23H2O, M = Sr, Ba, were obtained. Their crystal structure was determined by single crystal diffractometry. Sr(BF4)23H2O crystallizes in the tetragonal system, while Ba(BF4)23H2O crystallizes in the orthorhombic system. The crystal structure of these compounds is formed by isolated BF4 tetrahedra with alkali metal and water atoms between them. By fluorination of Li2B4O7, by its reaction with NH4BF4 in the range of 30–120 °C, NH4BF4, the fluoroborate Li2B3O4F3 was obtained.

Synthesis and Characterization of Chiral Iridium Complexes Bearing Carbohydrate Functionalized Pyridincarboxamide Ligands and Their Application as Catalysts in the Asymmetric Transfer Hydrogenation of α-Ketoacids in Water

[Cp*IrLnCl] complexes [L1 = (methyl-β-d-glucopyranosid-2-yl)picolinamide, 1; L2 = (methyl-3,4,6-tri-O-acetyl-β-d-glucopyranosid-2-yl)picolinamide, 2; L3 = (2,3,4,6-tetra-O-acetyl-β-d-glucopyranosid-1-yl)picolinamide, 3] have been synthesized and completely characterized in solution, by 1D- and 2D-NMR spectroscopy, and in the solid state, by X-ray single crystal diffractometry. Despite the chirality of the Ln-moiety and metal, a single diastereoisomer is observed for L1 (1) and L2 (2) having a (R)-iridium configuration: the pyranose moiety is oriented in a way to minimize the interactions of the axial protons, vicinal to the amide moiety, and Cp*, with the OMe-group pointing toward the Cp*-ligand and away from Ir–Cl. Such a diastereoisomer is also favored by the establishment of an O–H···Cl–Ir hydrogen bond (2.356 Å) and by the minimization of the steric repulsion between one acetyl moiety of L2 and Cp* and picolinamide ligands in 1 and 2, respectively. DFT calculations computed a stabilization by more than 5.9 and 3.1 kcal/mol of this diastereoisomer with respect to other possible ones. Two interconverting diastereoisomers with different chirality at iridium are instead observed in solution for complex 3 in which −CH2OAc [3a, 63%, (R)] and −OAc [3b, 37%, (S)] moieties, respectively, are oriented toward Cp* and N-arm of picolinamide ligands. Consistently, DFT calculations indicate that 3a and 3b have a comparable stability (ΔE = 1.2 kcal/mol). Complexes 1–3 catalyze the asymmetric transfer hydrogenation of RC(O)C(O)OH to RCH(OH)C(O)OH [R = Ph (PGA), CH2Ph (PPA), CH2(4-OH)C6H4 (HPPA)], using both HCOOH and H3PO3 as hydrogen donor, in water at pH 7 (by phosphate buffer), with excellent chemoselectivity and efficiency (conversion >99%) and moderate to good enantioselectivity (30–70% ee). Utilizing catalyst 3 instead of 2, bearing the pseudoenantiomeric L3 of L2 ligand, causes a reduction of the percentage of the major enantiomer (R) with PGA and an inversion of stereoselectivity from (R) to (S) with PPA and HPPA substrates.

Beamline setup for in situ measurements of particles in turbulent spray flames using small angle X-ray scattering

The particle formation in spray flame synthesis (SFS) is a fast and complex process involving many sub-steps that may happen simultaneously. To investigate the mechanisms that typically lead to small aggregated primary particles, a sophisticated technique for in situ measurements in the flame is necessary to provide information about primary particles and the aggregates as well. This work describes the development of an in situ measurement setup using small angle X-ray scattering (SAXS) to investigate the entire particle formation mechanism of zirconia nanoparticles in and above a turbulent spray flame. In preparation for the in situ measurements, a beamline for single crystal diffractometry at Karlsruhe Research Accelerator (KARA) was adapted for low scattering SAXS experiments including optimizations of the optics and measurement protocol. As a result, a significant dependence of scattering intensity was detected as a function of the height above the burner. A detailed analysis of the SAXS data and comparison with TEM images allow insights into the primary particle growth, the development of fractal properties and the aggregation process.

New Organic Salt from Levofloxacin-Citric Acid: What Is the Impact on the Stability and Antibiotic Potency?

This research dealt with the composition, structure determination, stability, and antibiotic potency of a novel organic salt composed of levofloxacin (LF) and citric acid (CA), named levofloxacin-citrate (LC). After a stoichiometric proportion screening, the antibiotic-antioxidant reaction was conducted by slow and fast evaporation methods. A series of characterizations using thermal analysis, powder X-ray diffractometry, vibrational spectroscopy, and nuclear magnetic resonance confirmed LC formation. The new organic salt showed a distinct thermogram and diffractogram. Next, Fourier transform infrared indicated the change in N-methylamine and carboxylic stretching, confirmed by 1H nuclear magnetic resonance spectra to elucidate the 2D structure. Finally, single-crystal diffractometry determined LC as a new salt structure three-dimensionally. The attributive improvements were demonstrated on the stability toward the humidity and lighting of LC compared to LF alone. Moreover, the antibiotic potency of LF against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) enhanced ~1.5–2-fold by LC. Hereafter, LC is a potential salt antibiotic-antioxidant combination for dosage formulas development.

Revealing the Configuration and Conformation of Surface Organometallic Catalysts with DNP-Enhanced NMR

Although single-site, supported organometallic catalysts were designed with homogeneity in mind, little is strictly known about their atomic-level structure and uniformity. This is in large part due to the inability of conventional characterization tools to provide structural information with adequate resolution and range for this purpose. Here, we show that dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (NMR) enables the measurement of distances between the surface and individual carbons, making it possible to orient complexes and molecules on surfaces. We use this approach to determine the orientation and configuration of naturally 13C-abundant acetate and supported organoiridium(III) pincer complex, both supported on γ-Al2O3. By combining solid-state NMR and extended X-ray absorption fine structure spectroscopy (EXAFS) experiments with periodic density functional theory (DFT) calculations, we are able to determine the three-dimensional arrangement of ligands around the metal center and thereby identify the structure of the supported complex at a resolution reminiscent of that associated with single-crystal diffractometry.

A dual‐channel ‘turn‐on’ fluorescent chemosensor for high selectivity and sensitivity detection of CN¯ based on a coumarin‐Schiff base derivative in an aqueous system

Novel strategies still need to be proposed, which can be used to identify and detect toxic environmental pollutants. In this paper, two channels of colorimetry and fluorescence "turn-on" fluorescent probe 1 (7-hydroxy-8-[(2-hydroxy- phenylimino)- methyl]-4-methylbenzopyran-2-one) for a simple yet highly selective detection of CN¯ have been successfully designed and synthesized. And the crystal features of probe 1 were defined by X-ray single crystal diffractometer. This probe 1 showed strongly colorimetric and fluorescent response to CN¯, which induces obvious naked-eye color changes in aqueous solution (DMSO/H2 O, 3:1 v:v), respectively. Besides, the probe 1 for CN¯ detection displayed low detection limits of 3.91 × 10-8 M, which is significantly lower than the 1.9 × 10-6 M maximum level specified by WHO for potable water. And the sensing mechanism of probe 1 was attributed to the deprotonation process by 1 H NMR titration. Moreover, based on the visible colorimetry and fluorescence change for the probe 1 to CN¯, the measurement was performed for simulated water samples containing CN¯. This study provides a broad prospect for solving other pollution problems and promoting the design of new fluorescent materials.

Preparation, spectral characterization and single crystal analysis of bromo derivative of 2-acetyl-1-naphthol

Present work deals with the synthesis of the 1-(4-bromo-1-hydroxynaphthalen-2-yl)ethan-1-one 3 from 2-acetyl-1-naphthol 2 using Br 2 /AcOH (20%) as brominating agent. The structure compound 3 was confirmed on the basis of spectral study such as FTIR, 1 H NMR, 13 C NMR and GCMS. The crystal structure of 4-bromo-2-acetyl-1-naphthol was also confirmed by the X-ray single-crystal diffractometry analysis and revealed the unit cell parameters, packing style. The single crystal has been grown by slow evaporation method at ambient temperature. The crystal size for compound 3 was found to be 0.150 × 0.120 × 0.100 mm3 . The crystal has grown with monoclinic crystal system with Z value of four and space group symmetry was P21/c. The unit cell parameters and angles were a; 7.3584 Å, b; 17.772 Å, c; 8.357 Å, α; 90°, β; 108.711°, √; 90°. The crystal structure of 3 is stabilized via one strong classical hydrogen bond interaction and two weak intermolecular hydrogen bonding. The observed average bond lengths of C C, C H, C O, C Br and O H bonds were 1.410, 0.941, 1.289, 1.899 and 0.80 Å respectively. Single crystal packing view of 1-(4-bromo-1-hydroxynaphthalen-2-yl)ethan-1-one

Permethylated dinuclear Mn(III) coordination nanostructure with stripe‐ordered magnetic domains

A di‐manganese(III) complex structure was built by an original approach consisting of a two‐step procedure. First, the mononuclear complex of the manganese(III) with the Schiff base of the salen‐type ligand (H2L) derived from 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane and 3,5‐di‐tert‐butyl‐2‐hydroxybenzaldehyde was prepared. The main feature of note is the 12‐membered chelate ring formed upon coordination of the Schiff base to central atom, which adopts a distorted N2O4 octahedron environment. In the second step, the acetato co‐ligand in this complex is replaced by the carboxylate anion of a dicarboxilic acid, namely adipic acid. This metathesis reaction leads to the formation of dinuclear structure by connecting two manganese centers. The structure, as was determined by X‐ray single crystal diffractometry, elemental and spectral analysis, is permethylated dinuclear complex with long aliphatic bridge. Thermal and magnetic properties were studied. In addition, the formation of magnetically induced stripe‐ordered domains was highlighted by the magnetic force microscopy (MFM) on films born from diluted solution.

Composing Novel Diclofenac Potassium and l-Proline Salt Cocrystal as a Strategy to Increase Solubility and Dissolution

This research dealt with the multicomponent crystal developed from diclofenac potassium and l-proline to improve the pharmaceutical performance of this anti-inflammatory drug. Slow evaporation of the component mixture at a 1:1 M ratio, supported by ultrasonication, yielded a new salt cocrystal, which was characterized using thermal analysis, Karl Fischer titration, infrared spectrophotometry, powder diffractometry, and single crystal diffractometry. This salt cocrystal was confirmed as a tetrahydrate that comprised diclofenac potassium, l-proline, and water (1:1:4), named DKPH. The new salt cocrystal enhanced the solubility of diclofenac potassium by up to 3.56 folds and accelerated the intrinsic dissolution rate of 3.36 folds. It was supported by the solid and solution phase intermolecular interaction study. A different phase, which indicated a monohydrate form of the salt cocrystal, was found from the low humidity chamber during the isotherm sorption study. However, the tetrahydrate, DKPH, was proven as a stable form under ambient conditions.

Design, synthesis, X-ray analysis, and biological screening of new oxime and enaminone thiazoline-2-thione derivatives

ABSTRACT An urgent need exists to develop antimicrobial and anticancer drugs that are safer and less prone to the development of resistance. To this end, a series of 12 new thiazoline-2-thione derivatives (oxime and enaminone) were synthesized using an appropriate synthetic route. The characterization of the newly synthesized compounds was performed using X-ray single-crystal diffractometry, elemental analysis, 1H NMR, 13C NMR, IR, and MS techniques. These compounds were then evaluated for their biological activities against a variety of microbes and human cancer cell lines. Our results revealed that the prepared thiazoline derivatives 4a, 4b, 6a, 6c, and 7 showed potent antifungal activity against Aspergillus fumigatus, comparable to the standard drugs. Additionally, all the thiazoline derivatives, except compound 4b, were effective against Candida albicans. The tested thiazolines also demonstrated potent antibacterial activity comparable to the standard drugs for all tested Gram-positive and Gram-negative bacterial species. The cytotoxicity evaluation of synthesized compounds 3, 6b and 7 against two cancer cell lines (HCT-116 and HepG-2) revealed that they had moderate cytotoxic activities, with compound 6b showing the best cytotoxic activity against the HCT-116 (IC50 = 79 µg/ml) and HepG-2 (IC50 = 49 µg/ml) cell lines. These findings open the pathway for the development of new lead compounds with chemotherapeutic properties.

Crystal structure and spectral properties of Np(VI) and U(VI) methanesulfonates

A new U(VI) complex with methanesulfonic acid was obtained [UO2(OH)(CH3SO3)]. Its crystal structure was determined using X-ray single crystal diffractometry. The compound crystallizes in P21/n space group. Main crystallographic data: a = 8.6825(6) A, b = 8.0551(6) A, c = 8.9298(7) A, β = 102.162(1)˚, V = 610.52(8) A3, Z = 4. Compound has a layered structure, with hydroxyl ions being bridging bidentate ligands and anions of methanesulfonic acid playing the role of bridging tridentate ligands. Np(VI) complex [NpO2(CH3SO3)2(H2O)], was also obtained and found to be isostructural to previously studied 1D polymorph of [UO2(CH3SO3)2(H2O)]. Main crystallographic data: space group P21/c, a = 11.2415(3) A, b = 7.9174(2) A, c = 10.8772(3) A, β = 99.656(1)˚, V = 954.39(4)A3, Z = 4. IR and UV–VIS–NIR spectra confirm structures of the compounds.

First titanium square fragment {Ti4(μ4-Se)(μ2-Se2)4} in its selenoiodide: Synthesis and structure of Ti4Se9I6

The first titanium selenoiodide Ti4Se9I6 was synthesized as black crystals by heating of Ti, Se, and I2 at 250 °C in 5:9:5 M ratio. The crystal structure of the compound was solved by X-ray single-crystal diffractometry (sp. gr. P-1, a = 7.9652(10), b = 10.3390(15), c = 15.692(2) Å; α = 79.116(7)°, β = 75.861(7)°, γ = 71.437(7)°; Z = 2) with final R1 = 0.0397. The structure includes square {Ti4(μ4-Se)(μ2-Se2)4} fragment coordinated by four terminal and four bridging μ2-I atoms. Ti4+ has d0 configuration, and stability of the structure fragments is provided by metal to ligand bonding which was confirmed by DFT calculations.

Quantum Chemistry, NMR Spectroscopy, and Single-Crystal Diffractometry Methods in the Analysis of Protonation Pathways of 2-Amino-4-benzylsulfanyl-6-methylpyrimidines

Protonation pathways of 2-amino-4-benzylsulfanyl-6-methylpyrimidines have been investigated by means of semiempirical PM3 quantum-chemical simulation, 13C NMR spectroscopy, and single-crystal diffractometry methods. In the gas phase and in the bipolar aprotic solvent, the protonation involves the N1 atom. The protonation in the crystalline state is characterized by the formation of a branched system of H-bonds, involving the protons of the amino group besides the mentioned nitrogen atom.

Dislocation Structure of Epitaxial Layers of AlGaN/GaN/α-Al2O3 Heterostructures Containing a GaN Layer Doped with Carbon and Iron

The aim of this work is to study the effect that the process of iron and carbon doping of a GaN epitaxial layer on sapphire can influence (affects) on the features of growth of epitaxial films and their dislocation structure. The following research methods are used in the study: secondary ion mass spectroscopy (SIMS), selective chemical etching of spherical sections, and single-crystal diffractometry. It is shown that carbon doping of a GaN epitaxial layer during growth can lead to a significant decrease in the dislocation density of the epitaxial layers. It is also demonstrated that, for samples doped with iron, a decrease in the number of short dislocations in the bulk of the structure is characteristic; however, a large number of extended dislocations are generated, encouraging iron diffusion into the working regions of the heterostructures, which is confirmed by the iron depth distribution of the layers, measured by the SIMS method.

Zn thiosacharinates: From ionic to polymeric structures. Synthesis, characterization and cell proliferation inhibition studies

Abstract A series of Zn thiosacharinates complexes with nitrogen donor co-ligands were synthesized: [Zn(tsac)2(o-phen)], [Zn(tsac)2(TMDP)]n, [(4,4′-bipy)H2][Zn(tsac)4] [Zn(tsac)2(2,2′-bipy)], [Zn(tsac)2(2,2′-bquin)], (tsac, thiosaccharinate anion: 1,1-dioxo-1,2-benzisothiazole-3-thiolato, C7H4NO2S2−, o-phen: 1,10′-phenantroline, TMDP: trimethylenedipyridine, 2,2′-bipy: 2,2′-bipyridine, 4,4′-bipy: 4,4′-bipyridine, 2,2′-bquin: 2,2′-biquinoline). They were fully characterized by means of FTIR, 13C and 1H NMR, elemental analysis and conductivity measurements. Three of them, [Zn(tsac)2(o-phen)], [(4,4′-bipy)H2][Zn(tsac)4], [Zn(tsac)2(TMDP)]n were also characterized by X-ray single crystal diffractometry and their crystal structures are described herein. DFT geometry optimization for the [Zn(tsac)2(o-phen)] complex was performed and its vibrational spectra was predicted. Moreover, we studied the effects of the five complexes on cell proliferation, thus providing preliminary evidence for their therapeutic potential as anti-cancer drugs.

Two new Zinc(II) and Cadmium(II) complexes of a semi-rigid bis(2-benzimidazole): Synthesis and characterization

ABSTRACTTwo new complexes Zn(TBimE)Cl2 1 and Cd(TBimE)(I)2 2 based on a semi-rigid ligand TBimE (TBimE = (E)-1,2-bis(2-benzimidazolyl)ethane) have been synthesized and their structures have been determined by X-ray single crystal diffractometry. X-ray diffraction analyses reveal that the “trans” TBimE is converted into “cis” conformation in the structures of the complexes, so that the TBimE can be used as a bidentate ligand to chelate the Zinc(II) and Cadmium(II) ions. Both 1 and 2 exhibit distorted tetrahedral geometries and the central metal atoms are coordinated by two N atoms from TBimE and two anions. The UV–Vis and emission spectra show that both the absorption and the emission of the complexes are assigned to the intraligand transitions and intraligand fluorescence, respectively.

Use of Stable Amine-Capped Polyynes in the Regioselective Synthesis of Push-Pull Thiophenes.

The reactions of a series of 1-halopolyynes with secondary amines led to novel amine end-capped polyynes exhibiting surprisingly high stability toward moisture. The new compounds were characterized by NMR spectroscopy, ESI-MS spectrometry, and X-ray single-crystal diffractometry. The use of amine end-capped polyynes as precursors to substituted push-pull thiophenes was next presented. The results show the first-to the best of our knowledge-transformation of ynamine to thiophene and the first regioselective transformation of a longer polyynes to butadiyne-substituted thiophene. Photophysical studies of the resulting compounds show that some of the substituted thiophenes have high quantum yield photoluminescence upon UV light irradiation.

New data reduction protocol for Bragg reflections observed by TOF single-crystal neutron diffractometry for protein crystals with large unit cells

In protein crystallography, high backgrounds are caused by incoherent scattering from the hydrogen atoms of protein molecules and hydration water. In addition, the scattering intensity from large unit-cell crystals is very small, which makes it difficult to improve the signal-to-noise ratio. In the case of time-of-flight (TOF) single-crystal neutron diffractometry, the measured spectra cover four-dimensional space including X, Y, and TOF in addition to intensity. When estimating the integrated intensity, 3D background domains in the vicinity of peaks should be clearly classified. In conventional 1D or 2D background evaluation, the evaluation is applied for individual peaks assigned using peak searches; however, it is quite difficult to classify the 3D background domain in TOF protein single-crystal neutron diffraction experiments. We undertook the development of a data reduction protocol for measurements involving large biomacromolecules. At the initial stage of the reduction protocol, appropriate 3D background estimation and eliminations were applied over the entire range of X, Y, and TOF bins. The histograms were then searched for peaks and indexed, and the individually assigned peaks were finally integrated with an effective profile function in the TOF direction. Three-dimensional deconvolution procedures for overlapping peaks associated with large unit cells were implemented as necessary. This data reduction protocol may lead to the improvement of signal-to-noise ratios to enable TOF spectral analysis of large unit-cell protein crystals.