scholarly journals Crystal engineering with pyrazolyl-thiazole derivatives: Structure-directing role of π-stacking and σ-hole interactions

CrystEngComm ◽  
2021 ◽  
Author(s):  
Muhammad Naeem Ahmed ◽  
Murtaza Madni ◽  
Shaista Anjum ◽  
Saiqa Andleeb ◽  
Shahid Hameed ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Noncovalent Interactions ◽  
Thiazole Derivatives ◽  
X Ray ◽  
Π Stacking

The synthesis and X-ray characterization of 1-(2-(3-(4-bromophenyl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-methylthiazol-5-yl)ethanone (7), ethyl 2-(5-(4-bromophenyl)-3-(4-chlorophenyl)-4,5-dihydropyrazol-1-yl)thiazole-4-carboxylate (8) and 2-(5-(4-chlorophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-N'-(2-hydroxy-3-methoxybenzylidene)thiazole-4-carbohydrazide (10) is described in this manuscript. The structure-directing role of a variety of noncovalent interactions have been...

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

Synthesis and crystallographic studies of two new 1,3,5-triazines

2020 ◽  
Vol 76 (4) ◽  
pp. 322-327
Author(s):  
Emmanuel Blas Patricio-Rangel ◽  
Margarita Tlahuextl ◽  
Hugo Tlahuext ◽  
Antonio Rafael Tapia-Benavides
Keyword(s):  
Noncovalent Interactions ◽  
Synthesis And Characterization ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positional Disorder ◽  
Hydrated Salt ◽  
Symmetry Space ◽  
Symmetry Space Group

The synthesis and characterization of two new 1,3,5-triazines containing 2-(aminomethyl)-1H-benzimidazole hydrochloride as a substituent are reported, namely, 2-{[(4,6-dichloro-1,3,5-triazin-2-yl)amino]methyl}-1H-benzimidazol-3-ium chloride, C11H9Cl2N6 +·Cl− (1), and bis(2,2′-{[(6-chloro-1,3,5-triazine-2,4-diyl)bis(azanediyl)]bis(methylene)}bis(1H-benzimidazol-3-ium)) tetrachloride heptahydrate, 2C19H18ClN9 2+·4Cl−·7H2O (2). Both salts were characterized using single-crystal X-ray diffraction analysis and IR spectroscopy. Moreover, the NMR (1H and 13C) spectra of 1 were obtained. Salts 1 and 2 have triclinic symmetry (space group P-1) and their supramolecular structures are stabilized by hydrogen bonding and offset π–π interactions. In hydrated salt 2, the noncovalent interactions yield pseudo-nanotubes filled with chloride anions and water molecules, which were modelled in the refinement with substitutional and positional disorder.

scholarly journals The Role of Percent Volume Buried in the Characterization of Copper(I) Complexes for Lighting Purposes

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2647 ◽  
Author(s):  
Murat Alkan-Zambada ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Quantum Yields ◽  
X Ray ◽  
Photophysical Behavior

The usefulness of percent volume buried (%Vbur) as a readily quantifiable property is investigated with regard to [Cu(NN)(PP)]+ complexes of interest for lighting purposes. Photoluminescence quantum yields (PLQYs) and single crystal X-ray structures of 100 reported compounds were assembled, %Vbur of the ligand systems were calculated and analyzed for correlations. We found that increased shielding of the central Cu(I) cation relying on shared contributions of both (NN) and (PP) ligand systems led to increased PLQYs. These findings are of relevance for future characterizations of Cu(I)-based complexes and their photophysical behavior in the solid-state.

scholarly journals Structural characterization of gephyrin by AFM and SAXS reveals a mixture of compact and extended states

2013 ◽  
Vol 69 (10) ◽  
pp. 2050-2060 ◽  
Author(s):  
Bodo Sander ◽  
Giancarlo Tria ◽  
Alexander V. Shkumatov ◽  
Eun-Young Kim ◽  
J. Günter Grossmann ◽  
...  
Keyword(s):  
Conformational Dynamics ◽  
Cd Spectroscopy ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Extended States ◽  
High Degree

Gephyrin is a trimeric protein involved in the final steps of molybdenum-cofactor (Moco) biosynthesis and in the clustering of inhibitory glycine and GABAAreceptors at postsynaptic specializations. Each protomer consists of stably folded domains (referred to as the G and E domains) located at either terminus and connected by a proteolytically sensitive linker of ∼150 residues. Both terminal domains can oligomerize in their isolated forms; however, in the context of the full-length protein only the G-domain trimer is permanently present, whereas E-domain dimerization is prevented. Atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS) reveal a high degree of flexibility in the structure of gephyrin. The results imply an equilibrium between compact and extended conformational states in solution, with a preference for compact states. CD spectroscopy suggests that a partial compaction is achieved by interactions of the linker with the G and E domains. Taken together, the data provide a rationale for the role of the linker in the overall structure and the conformational dynamics of gephyrin.

Growth and characterization of Al–Cu–Li quasicrystals

1988 ◽  
Vol 3 (2) ◽  
pp. 233-237 ◽  
Author(s):  
J. M. Parsey ◽  
H. S. Chen ◽  
A. R. Kortan ◽  
F. A. Thiel ◽  
A. E. Miller ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Alloy System ◽  
Icosahedral Phase ◽  
Solidification Velocity ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pseudobinary Phase Diagram ◽  
Melt Composition

The alloy system Al–Li–Cu was investigated extensively over the composition range 5.8–8 Al–Cu–3Li to develop a detailed understanding of the formation and properties of the icosahedral phase, known as T2. Material from the various charges was analyzed by optical and electron microscopy, energy dispersive x-ray analysis, differential thermal analysis, and differential scanning calorimetry. The role of the melt composition and the solidification velocity were found to be crucial in determining the micro- and macrostructure and the existence of the icosahedral phase. A pseudobinary phase diagram for the region around Al6CuLi3, is presented based on these analyses. Based on this phase diagram the largest single icosahedral crystals of Al5.1CuLi3 yet reported, with diameters greater than 1 cm, were produced by Bridgman methods.

scholarly journals Synthesis of Iron Oxide Nanoparticles Using Isobutanol

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Diana Kostyukova ◽  
Yong Hee Chung
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Ammonium Hydroxide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Ferrous Chloride ◽  
X Ray ◽  
Superparamagnetic Properties

Iron oxide nanoparticles were synthesized by precipitation in isobutanol with sodium hydroxide and ammonium hydroxide. The isobutanol played a role of a surfactant in the synthesis. The nanoparticles were calcined for 100 min to 5 hours in the range of 300 to 600°C. The characterization of the samples by FTIR (Fourier-transform infrared) and XRD (X-ray diffraction) confirmed the formation ofγ-Fe2O3(maghemite) from Fe3O4(magnetite) at calcination at 300°C. The morphology and particle size were studied by SEM (scanning electron microscope). Nanoparticles in the range of 11–22 nm prepared at 0.09 M of ferrous chloride exhibited superparamagnetic properties. Nanoparticles synthesized with ferrous chloride and ammonium hydroxide at 75°C and calcined at 530°C for 2 h wereα-Fe2O3(hematite).

scholarly journals Growth and Characterization of High-Quality GaN Nanowires on PZnO and PGaN by Thermal Evaporation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
L. Shekari ◽  
H. Abu Hassan ◽  
S. M. Thahab ◽  
Z. Hassan
Keyword(s):  
Gallium Nitride ◽  
Thermal Evaporation ◽  
Lattice Mismatch ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gan Nanowires ◽  
Transmission Electron

In the current research, an easy and inexpensive method is used to synthesize highly crystalline gallium nitride (GaN) nanowires (NWs) on two different substrates [i.e., porous zinc oxide (PZnO) and porous gallium nitride (PGaN)] on Si (111) wafer by thermal evaporation without any catalyst. Microstructural studies by scanning electron microscopy and transmission electron microscope measurements reveal the role of the substrates in the nucleation and alignment of the GaN NWs. Further structural and optical characterizations were performed using high-resolution X-ray diffraction, energy-dispersive X-ray spectroscopy, and photoluminescence spectroscopy. Results indicate that the NWs have a single-crystal hexagonal GaN structure and growth direction in the (0001) plane. The quality and density of GaN NWs grown on different substrates are highly dependent on the lattice mismatch between the NWs and their substrates. Results indicate that NWs grown on PGaN have better quality and higher density compared to NWs on PZnO.

Characterization of CdTe:Zn:V crystals grown under microgravity conditions

2002 ◽  
Vol 17 (12) ◽  
pp. 3037-3041 ◽  
Author(s):  
V. Corregidor ◽  
V. Babentsov ◽  
J. L. Castaño ◽  
M. Fiederle ◽  
T. Feltgen ◽  
...  
Keyword(s):  
Growth Process ◽  
Structural Quality ◽  
Seed Region ◽  
Photoluminescence Spectra ◽  
Positive Role ◽  
X Ray ◽  
Microgravity Conditions

CdTe:Zn:V crystals grown by the seeded Bridgman method in microgravity conditions during the STS95-Spacelab-AGHF-1 mission and in the ground laboratory (l-g) were analyzed and compared. The results obtained clearly show that the structural quality of the space crystal is better. Density of inclusions, concentration of dislocations, and presence of stresses are lower in the microgravity-grown (μ-g) crystal. The l-g crystal contains twins and grains from the beginning of the growth process, that is, from the near-seed region. In general, the concentration of inclusions and amount of segregated impurities on the l-g crystal are larger than in the μ-g crystal. X-ray rocking curves and low-temperature photoluminescence spectra demonstrate the relatively high quality of both crystals on a microscale at the beginning of the growth and show that the l-g conditions were worse at the end. The results of this investigation demonstrate a positive role of contactless growth and μ-g conditions in the melt in suppressing the creation of inclusions and dislocations.

scholarly journals Synthesis and characterization of 2CuCN·DMSO and [CuII(DMSO)6][CuI 6(CN)8] 3-D framework compounds

2013 ◽  
Vol 11 (6) ◽  
pp. 1001-1009 ◽  
Author(s):  
Andrii Vakulka ◽  
Evgeny Goreshnik
Keyword(s):  
Raman Spectroscopy ◽  
Mixed Valence ◽  
Synthesis And Characterization ◽  
Ligand Molecule ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anionic Framework ◽  
Framework Compounds

AbstractTwo novel complexes of CuCN were characterized by using a single-crystal X-ray diffraction technique and Raman spectroscopy. In the structure of 2CuCN·DMSO ligand molecule demonstrates unique bridging mode, being bound to two CuI centers via oxygen and sulfur atoms. The bridging role of both CN groups and DMSO molecules results in the formation of (CuCN·DMSO)n framework. Along the channels of the network are running infinite zig-zag (CuCN)n chains, which are bound to the framework by elongated Cu…(CN) bonds. A mixed-valence [CuII(DMSO)6][CuI 6(CN)8] compound is composed of 3-D [CuI 6(CN)8]n anionic framework and located in the channels of partially disordered [CuII(DMSO)6]2+ cations.

Synthesis and Characterization of Flower-Like Hematite Nanostructures

2011 ◽  
Vol 287-290 ◽  
pp. 169-172
Author(s):  
Hong Wang ◽  
Xi Yang He ◽  
Ying Wang
Keyword(s):  
Electron Microscopy ◽  
Average Length ◽  
Critical Role ◽  
Average Diameter ◽  
Synthesis And Characterization ◽  
Hydrothermal Route ◽  
X Ray ◽  
Scanning Electron

The flower-like α-Fe2O3superstructures were fabricated by a novel hydrothermal route and sequential annealing at 600 °C for 1 h using FeCl3×6H2O as the starting precursor. The structures and morphologies of the synthesized flower-like superstructures have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM). It is revealed that the flower-like α-Fe2O3nanostructures consist of nanorods with the average diameter of about 70 nm and an average length of about 200nm growing from the centers. The critical role of urea in the hydrothermal synthesis of the flower-like nanostructures is discussed.

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