scholarly journals Ligand pathways in neuroglobin revealed by low-temperature photodissociation and docking experiments

IUCrJ ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 832-842 ◽  
Author(s):  
Chiara Ardiccioni ◽  
Alessandro Arcovito ◽  
Stefano Della Longa ◽  
Peter van der Linden ◽  
Dominique Bourgeois ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Storage Site ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Biophysical Approach ◽  
The Central Nervous System ◽  
Uv Visible ◽  
X Ray Absorption

A combined biophysical approach was applied to map gas-docking sites within murine neuroglobin (Ngb), revealing snapshots of events that might govern activity and dynamics in this unique hexacoordinate globin, which is most likely to be involved in gas-sensing in the central nervous system and for which a precise mechanism of action remains to be elucidated. The application of UV–visible microspectroscopy in crystallo, solution X-ray absorption near-edge spectroscopy and X-ray diffraction experiments at 15–40 K provided the structural characterization of an Ngb photolytic intermediate by cryo-trapping and allowed direct observation of the relocation of carbon monoxide within the distal heme pocket after photodissociation. Moreover, X-ray diffraction at 100 K under a high pressure of dioxygen, a physiological ligand of Ngb, unravelled the existence of a storage site for O2 in Ngb which coincides with Xe-III, a previously described docking site for xenon or krypton. Notably, no other secondary sites were observed under our experimental conditions.

scholarly journals Microwave-Assisted Synthesis and Characterization of [Rh2(OAc)4(L)2] Paddlewheel Complexes: A Joint Experimental and Computational Study

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Oscar F. Gonzalez-Belman ◽  
Yazmín Varela ◽  
Marcos Flores-Álamo ◽  
Kazimierz Wrobel ◽  
Silvia Gutierrez-Granados ◽  
...  
Keyword(s):  
Computational Study ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
Experimental Conditions ◽  
X Ray ◽  
Paddlewheel Complexes ◽  
Uv Visible ◽  
Insight Into

The synthesis of four rhodium(II) paddlewheel complexes bearing axial aromatic amines and coumarin ligands, with formula [Rh2(OAc)4(L)2] (L = NH2Mesityl (1), NH2Dip (2), NH2Couma (3), coumarin (4)), prompted by microwave irradiation, was carried out successfully. All of the complexes were characterized by the melting point, elemental analysis, NMR, IR, and UV/Visible spectroscopy. Additionally, the structure of complexes 1-2 and 4 was corroborated by single-crystal X-ray diffraction. Cyclic voltammetry, ESI-MS, and tandem MS analyses were carried out in compound 1 for gaining further insight into its stability. Finally, a DFT study shows that complexes 1–4 are the thermodynamic products, having as intermediates complexes 1′–4′ which, under our experimental conditions, cannot be isolated.

Characterization of New Nonstoichiometric Ferroelectric (Li0.95Cu0.15)Ta0.76Nb0.19O3 and Comparative Study With (Li0.95Cu0.15)Ta0.57Nb0.38O3 as Photocatalysts in Microbial Fuel Cells

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
S. Louki ◽  
N. Touach ◽  
A. Benzaouak ◽  
V. M. Ortiz-Martínez ◽  
M. J. Salar-García ◽  
...  
Keyword(s):  
Power Density ◽  
Microbial Fuel Cells ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ferroelectric Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Uv Visible

This work investigates the photocatalytic activity of new ferroelectric material with formula (Li0.95Cu0.15)Ta0.76Nb0.19O3 (LT76) in a single chamber microbial fuel cell (MFC) and compares its performance with the similar photocatalyst (Li0.95Cu0.15)Ta0.57Nb0.38O3 (LT57). The photocatalysts LT76 and LT57 were synthesized by ceramic route under the same conditions, with the same starting materials. The ratio Ta/Nb was fixed at 4.0 and 1.5 for LT76 and LT57, respectively. These phases were characterized by different techniques including X-ray diffraction (XRD), transmission electronic microscopy (TEM), particle size distribution (PSD), differential scanning calorimetry (DSC), and ultraviolet (UV)–visible (Vis). The new photocatalyst LT76 presents specific surface area of 0.791 m2/g and Curie temperature of 1197 °C. The photocatalytic efficiency of this material is assessed in terms of wastewater treatment and electricity generation by power density and removal rate of chemical oxygen demand (COD) in the presence of a light source. The values of maximum power density and COD removal were 19.77 mW/m3 and 93%, respectively, for LT76.

scholarly journals Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Daisuke Ogawa ◽  
Ryo Kitaura ◽  
Takeshi Saito ◽  
Shinobu Aoyagi ◽  
Eiji Nishibori ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Yield ◽  
Single Wall Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Wall Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Organometallic Molecules ◽  
X Ray Absorption

Thermally fragile tris(η5-cyclopentadienyl)erbium (ErCp3) molecules are encapsulated in single-wall carbon nanotubes (SWCNTs) with high yield. We realized the encapsulation of ErCp3with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+) is confirmed by X-ray absorption spectrum.

Synthesis and Electrochemistry of Aluminum Porphycenes: Crystal and Molecular Structure of Methyl-σ-Bonded Aluminum Etioporphycene

1997 ◽  
Vol 01 (02) ◽  
pp. 109-119 ◽  
Author(s):  
ROGER GUILARD ◽  
VIRGINIE PICHON-PESME ◽  
HASSANE LACHEKAR ◽  
CLAUDE LECOMTE ◽  
ALLY M. AUKAULOO ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Structural Data ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Axial Ligands ◽  
Uv Visible

The synthesis and characterization of three monomeric aluminum porphycenes with anionic or σ-bonded axial ligands is reported. The investigated compounds are represented as ( EtioPc ) Al ( CH 3) and ( EtioPc ) AlX where EtioPc represents the dianion of etioporphycene and X = Cl − or OH −. Each synthesized complex was characterized by mass spectrometry. 1 H NMR, IR and UV-visible spectroscopies as well as by electrochemistry. Comparisons are made between the properties of complexes in the aluminum etioporphycene series and related chloro- or methyl σ-bonded Al ( III ) porphyrins containing octaethylporphyrin ( OEP ) or tetraphenylporphyrin ( TPP ) macrocycles. Comparisons are also made between the currently investigated compounds and a previously reported Al ( III ) μ-oxo dimer, [( EtioPc ) Al ]2 O . In addition, the crystal and molecular structure of ( EtioPc ) Al ( CH 3) was determined by X-ray diffraction. The molecular structure of this methyl-σ-bonded aluminum etioporphycene provides the first structural data for an aluminum porphycene compound. The aluminum(III) atom in ( EtioPc ) Al ( CH 3) is pentacoordinated and is located 0.54 Å from the plane of the four N -nitrogens.

In Situ Polymerization and Characterization of Poly(ε-caprolactone)/Layered Double Hydroxide Nanocomposites

2012 ◽  
Vol 557-559 ◽  
pp. 371-374
Author(s):  
Lian Liu ◽  
Teng Yu ◽  
Pei Wang ◽  
Guang Shuo Wang
Keyword(s):  
Layered Double Hydroxide ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Uv Visible ◽  
Absorbance Peak ◽  
Double Hydroxide

Nanocomposites of poly(ε-caprolactone) (PCL) and layered double hydroxide (LDH) were prepared by in situ polymerization at low LDHs loadings in this work. The resultants were characterized by FTIR spectroscopy, X-ray diffraction (XRD), differential scanning calorimeter (DSC) and UV-visible spectroscopy (UV-vis). FTIR showed that the PCL/LDHs nanocomposites were prepared successfully by in situ polymerization and XRD spectra showed that the crystal structure did not change greatly in the presence of LDHS. DSC results confirmed that LDHs could act as nucleating agents. UV-vis spectra showed that LDHs had stronger absorbance peak than LDH. Moreover, the PCL/LDHs nanocomposites had strong anti-ultraviolet effect by introduction of LDHs into polymer matrix.

On X-Ray Diffraction and X-Ray Absorption Spectroscopy Characterization of Ball Milled Iron Copper Solid Solution

1998 ◽  
Vol 269-272 ◽  
pp. 473-478 ◽  
Author(s):  
Francsco Cardellini ◽  
Vittoria Contini ◽  
Gregorio D'Agostino ◽  
Adriano Filipponi
Keyword(s):  
Solid Solution ◽  
Absorption Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Copper ◽  
X Ray Absorption

Microwave-Hydrothermal Synthesis and Characterization of Graphene

2012 ◽  
Vol 602-604 ◽  
pp. 917-920 ◽  
Author(s):  
Zhen Hui Xiao ◽  
Shui Sheng Wu ◽  
Yan Lin Sun ◽  
Yu Lin Zhao ◽  
Ya Ming Wang
Keyword(s):  
Chemical Reduction ◽  
Visible Spectrum ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Hydrothermal ◽  
Ft Ir ◽  
Uv Visible ◽  
Scanning Electron

Graphene was synthesized by microwave-hydrothermal chemical reduction of graphite oxide using hydrazine hydrate as the reducing agent. Graphene was characterized using X-ray diffraction, UV-visible spectrum, FT-IR spectrum and scanning electron microscopy. Results indicated that the as-prepared graphene was wrinkled and comprised fewer graphenes with a highly crystalline structure.

scholarly journals Characterization of CuO thin films for gas sensing applications

2019 ◽  
Vol 14 (31) ◽  
pp. 1-12
Author(s):  
Jamal M. Rzaij
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Cupric Oxide ◽  
Laser Pulses ◽  
X Ray Diffraction ◽  
Energy Increase ◽  
Nano Structure ◽  
X Ray ◽  
Sensing Applications

Nanostructural cupric oxide (CuO) films were prepared on Si and glass substrate by pulsed laser deposition technique (PLD) using laser Nd:YAG, using different laser pulses energies from 200 to 600 mJ. The X-ray diffraction pattern (XRD) of the films showed a polycrystalline structure with a monoclinic symmetry and preferred orientation toward (111) plane with nano structure. The crystallite size was increasing with increasing of laser pulse energy. Optical properties was characterized by using UV–vis spectrometer in the wave lengthrange (200-1100) nm at room temperature. The results showed that the transmission spectrum decreases with the laser pulses energy increase. Sensitivity of NO2 gas at different operating temperatures, (50°C, 100°C, 150°C and 200°C) was calculated.

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