Elucidating the crystal structure of the antimalarial drug (±)-mefloquine hydrochloride: a tetragonal hydrated species

2014 ◽  
Vol 47 (4) ◽  
pp. 1380-1386 ◽  
Author(s):  
Vânia Mendes do Prado ◽  
Rafael Cardoso Seiceira ◽  
Altivo Pitaluga Jr ◽  
Tarciso Andrade-Filho ◽  
Wendel Andrade Alves ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Fourier Transform ◽  
Biological Activity ◽  
Infrared Spectroscopy ◽  
Antimalarial Drug ◽  
Theoretical Calculations ◽  
Active Pharmaceutical Ingredient ◽  
Hydrated Form ◽  
X Ray ◽  
Structure And Bonding

Albeit widely studied, the structure of the antimalarial drug (±)-mefloquine hydrochloride is still a controversial issue. A combination of X-ray powder diffraction, theoretical calculations and Fourier transform–infrared spectroscopy is used to unambiguously determine the crystal structure of the molecule in its active pharmaceutical ingredient. It is demonstrated that water is incorporated into the structure, leading to a hydrated form and, most importantly, to significant differences in both structure and bonding. Such changes can lead to significant differences in biological activity.

scholarly journals Effects of removal of extractives on the chemical composition and mechanical properties of wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8631-8647
Author(s):  
Dongliang Zhao ◽  
Haibiao Yu ◽  
Xiuchun Bao ◽  
Jinwei Liu ◽  
Haoqiang Yuan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Great Influence ◽  
Wood Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Extraction Treatment ◽  
Adsorption Of N2

Poplar and pine wood were extracted with water, 1% NaOH (wt%) solution, and benzene:ethanol solution (V1 : V2, 2 : 1) to investigate the governing factors and mechanism by which extractives affect wood structure and mechanical properties. The structure, pore distribution, crystal structure, and mechanical properties of samples were analyzed by Fourier transform infrared spectroscopy (FTIR), adsorption of N2 gas, X-ray diffraction (XRD), and mechanical testing, respectively. The results demonstrated that cellulose, hemicellulose, and lignin were degraded to some extent in the course of the dissolution of the extractives. This degradation had a great influence on the structure and quantity of pores. The extraction treatment did not change the crystallization type of the wood, but it increased the crystallinity of the wood, and the length and width of the crystallization area changed. In addition, the mechanical properties of wood were changed when the content of the extractives was reduced.

Effect of Polyaniline on Structural and Optical Characteristics of Fe3O4 and TiO2 Nanoparticles

2020 ◽  
Vol 851 ◽  
pp. 9-15
Author(s):  
Ahmad Taufiq ◽  
M.Sofiyudin Nuroni ◽  
Nurul Hidayat ◽  
ST.Ulfawanti Intan Subadra ◽  
Sunaryono ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Data Analysis ◽  
Diffraction Data ◽  
Functional Group ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray

In this work, Fe3O4 nanoparticles (NPs) were synthesized using coprecipitation method and TiO2 NPs were synthesized using sonication method. Fe3O4/polyaniline and TiO2/polyaniline nanocomposites (NCs) were synthesized using polymerization methods. The samples were characterized by X-ray diffractometer, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. The results of X-ray diffraction data analysis presented that polyaniline decreased the crystallinity of Fe3O4 and TiO2 NPs. However, the crystal structure of Fe3O4 and TiO2 NPs did not change, which successively formed the cubic spinel and the tetragonal anatase phases. Furthermore, the functional groups of Ti-O-Ti and Fe-O were detected in the wavenumber ranges of 620-580 cm-1 and 410-520 cm-1, respectively. The presence of polyaniline was also detected by the emergence of a functional group of polyaniline which also showed that there was an interaction of Fe3O4 and TiO2 NPs with polyaniline. Meanwhile, the results of UV-Vis data analysis showed that the addition of polyaniline decreased the bandgap energy of Fe3O4 and TiO2 NPs significantly from 2.186 to 2.174 eV and from 3.374 to 3.320 eV, respectively.

Multidisciplinary Investigations of a Double Sided Wooden Icon from Nicula Monastery, Romania

2019 ◽  
Vol 70 (8) ◽  
pp. 2747-2752
Author(s):  
Constantin Marutoiu ◽  
Ioan Bratu ◽  
Mircea Gelu Buta ◽  
Olivia Florena Nemes ◽  
Sergiu Petru Timbus(Monk Siluan) ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Spectroscopic Methods ◽  
X Ray ◽  
Painting Materials ◽  
The Status

A two-sided wooden icon from a monastery in Transylvania was submitted for multidisciplinary investigations involving X-Ray Fluorescence, Radiographic Photographyand Fourier Transform Infrared Spectroscopy. The most important part of the icon is St. Nicholas wooden icon, painted over forty years ago. The spectroscopic methods used revealed the painting materials composition, the status of the wooden stage, and the presence of resins as varnish (Fourier Transform Infrared Spectroscopy). On one side, the St Nicholasicon was painted over an old icon, St. Arch. Michael, which was evidenced by X-Ray Photography. The obtained data can serve for the preservation and the restoration of these wooden icons.

Second-Generation Inhibitors for the Metalloprotease Neprilysin Based on Bicyclic Heteroaromatic Scaffolds: Synthesis, Biological Activity, and X-Ray Crystal-Structure Analysis

2005 ◽  
Vol 88 (4) ◽  
pp. 731-750 ◽  
Author(s):  
Stefan Sahli ◽  
Brian Frank ◽  
W. Bernd Schweizer ◽  
François Diederich ◽  
Denise Blum-Kaelin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biological Activity ◽  
Structure Analysis ◽  
Second Generation ◽  
Crystal Structure Analysis ◽  
X Ray

scholarly journals Changes of Pd Oxidation State in Pd/Al2O3 Catalysts Using Modulated Excitation DRIFTS

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 116
Author(s):  
Gian Luca Chiarello ◽  
Ye Lu ◽  
Miren Agote-Arán ◽  
Riccardo Pellegrini ◽  
Davide Ferri
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Oxidation State ◽  
Diffuse Reflectance ◽  
X Ray ◽  
Spectral Changes ◽  
Diffuse Reflectance Infrared ◽  
X Ray Absorption ◽  
Reversible Reduction

Infrared spectroscopy is typically not used to establish the oxidation state of metal-based catalysts. In this work, we show that the baseline of spectra collected in diffuse reflectance mode of a series of Pd/Al2O3 samples of increasing Pd content varies significantly and reversibly under alternate pulses of CO or H2 and O2. Moreover, these baseline changes are proportional to the Pd content in Pd/Al2O3 samples exhibiting comparable Pd particle size. Similar measurements by X-ray absorption spectroscopy on a different 2 wt.% Pd/Al2O3 confirm that the baseline changes reflect the reversible reduction-oxidation of Pd. Hence, we demonstrate that changes in oxidation state of metal-based catalysts can be determined using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and that this behavior is part of the spectral changes that are returned by experiments under operando conditions.

Synthesis and Crystal Structure of the Flexible Ligand Coordination Polymer [Co3(bpd)5.5(NCS)6(NH3)]n⋅2H2O(bpd= 1,4-bis (4-pyridyl)-2,3-diaza-1,3-butadiene)

2013 ◽  
Vol 803 ◽  
pp. 80-84
Author(s):  
Yu Qi Liu ◽  
Yong Yang ◽  
Rui Yang ◽  
Xiao Jun Xu
Keyword(s):  
Crystal Structure ◽  
Infrared Spectroscopy ◽  
Coordination Polymer ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Elemental Analyses ◽  
Ligand Coordination ◽  
Point Symbol

A novel metalorganic coordination polymer, namely [Co3(bpd)5.5(NCS)6(NH3)]n2H2O (1) (bpd=1,4-bis (4-pyridyl)-2,3-diaza-1,3-butadiene), has been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Compound 1 presents 2D[3,4,-connected 3-nodal net with the point symbol (4268210)(4462)(8210). In addition, four identical 2D single nets is interlocked with each other in parallel, thus directly leading to the formation of a polycatenated layer (2D2D).

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