scholarly journals Effect of Aromatic System Expansion on Crystal Structures of 1,2,5-Thia- and 1,2,5-Selenadiazoles and Their Quaternary Salts: Synthesis, Structure, and Spectroscopic Properties

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4908
Author(s):  
Jan Alfuth ◽  
Beata Zadykowicz ◽  
Artur Sikorski ◽  
Tadeusz Połoński ◽  
Katarzyna Eichstaedt ◽  
...  

Rational manipulation of secondary bonding interactions is a crucial factor in the construction of new chalcogenadiazole-based materials. This article reports detailed experimental studies on phenanthro[9,10-c][1,2,5]chalcogenadiazolium and 2,1,3-benzochalcogenadiazolium salts and their precursors. The compounds were synthesized, characterized employing NMR and UV-Vis spectroscopy. TD-DFT calculations were also performed. The influence of the size of the aromatic system on the molecular motifs formed by the compounds in the solid state has been studied by means of single-crystal X-ray diffraction. In case of the salts, the nature of an anion was also taken into consideration. The results show that cyclic [E···N]2 supramolecular synthon connects neighboring molecules of phenanthro[9,10-c][1,2,5]chalcogenadiazoles, with a relatively large aromatic system, in dimers regardless of the chalcogen atom in the molecule. Both N-methyl-2,1,3-benzothiadiazolium and N-methylphenanthro[9,10-c][1,2,5]chalcogenadiazolium cations have a strong affinity for triflate and iodide anions, therefore the formation of S···N or Se···N secondary bonding interactions is observed only in two out of the eight quaternary salts. Less coordinating anions must be used to enable the building blocks studied to form cyclic [E···N]2 synthons. Moreover, for two of the triflate salts, which are isostructural, a new supramolecular motif has been observed.

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3029
Author(s):  
Wojciech Sas ◽  
Dawid Pinkowicz ◽  
Marcin Perzanowski ◽  
Magdalena Fitta

Over recent years, investigations of coordination polymer thin films have been initiated due to their unique properties, which are expected to be strongly enhanced in the thin film form. In this work, a crystalline [FeII(H2O)2]2[NbIV(CN)8]∙4H2O (1) film on a transparent Nafion membrane was obtained, for the first time, via ion-exchange synthesis. The proper film formation and its composition was confirmed with the use of energy dispersive X-ray spectroscopy and infrared spectroscopy, as well as in situ Ultraviolet-Visible (UV-Vis) spectroscopy. The obtained film were also characterized by scanning electron microscopy, X-ray diffraction, and magnetic measurements. The [FeII(H2O)2]2[NbIV(CN)8]∙4H2O film shows a sharp phase transition to a long-range magnetically ordered state at Tc = 40 K. The 1 film is a soft ferromagnet with the coercive field Hc = 1.2 kOe. Compared to the bulk counterpart, a decrease in critical temperature and a significant increase in the coercive field were observed in the films indicating a distinct size effect. The decrease in Tc could also have been related to the possible partial oxidation of FeII ions to FeIII, which could be efficient, due to the large surface of the thin film sample.


2018 ◽  
Vol 34 (5) ◽  
pp. 2673-2676
Author(s):  
Humaira Rani ◽  
Vijay Kumar Singh ◽  
Shafaque Asif ◽  
Mohammad Israil Ansari

Metallic nanoparticles, one of the building blocks of nanotechnology, have a variety of applications because of their unique and interesting properties. In this study, we have done the synthesis of silver nanoparticles (AgNPs) by “bottom-up” technique using an extract of Psoralea corylifolia (Babchi) and silver nitrate (AgNO3). The synthesis of AgNPs was monitored by ultraviolet-visible absorption spectroscopy. Primary characterization by UV-Vis spectroscopy and scanning electron microscopy (SEM) micrograph depicted that the synthesized nanoparticles of spherical and cubical in shape with uniform size distribution. In addition, the X-ray diffraction (XRD) further revealed that the nanoparticles were of the size ranging from 50-100 nm.


2014 ◽  
Vol 70 (5) ◽  
pp. 432-436 ◽  
Author(s):  
Ivan Potočňák ◽  
Lucia Váhovská ◽  
Peter Herich

Two new diamagnetic coordination compounds, [Fe(phen)3][C(CN)3]2, (I), and [Fe(bpy)3][C(CN)3]2·1.5H2O, (II), have been synthesized and characterized by single-crystal X-ray diffraction analysis, and IR and UV–Vis spectroscopy (phen is 1,10-phenanthroline, C12H8N2, and bpy is 2,2′-bipyridine, C10H8N2). Both compounds are ionic with distorted octahedral [Fe(phen)3]2+ or [Fe(bpy)3]2+ complex cations, with average Fe—N distances of 1.977 (2) and 1.971 (3) Å, respectively, and two uncoordinated planar tricyanomethanide, or [C(CN)3]−, counter-anions balancing the positive charges of the cations. Solvent water molecules and tcm anions in (II) are linked via O—H...N hydrogen bonds into negatively charged layers and the interlayer space is filled by [Fe(bpy)3]2+ cations. The structures of (I) and (II) are stabilized by π–π interactions between the stacked aromatic rings of the phen ligands of two adjacent cations and by O—H...N hydrogen bonds, respectively, and also by π–π stacking interactions between phen and tcm units in (I).


Author(s):  
S.N. Shreenivasan ◽  
C. Chinnasamy

In this study an experimental investigation has been carried out on diesel engine to understand the engine behaviour with respect to its performance and emission characteristics while using Aluminium oxide (Al2O3) Nano particle as additive with a blend of diesel and biodiesel sourced from Waste Plastic Oil (WPO). The Alumina Nano particles are characterized by X- ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) analysis, UV-Vis Spectroscopy and Zeta Potential Analysis. The alumina Nano particles are blended with Waste Plastic Oil in the mass fractions of 10 and 20 ppm using an Ultrasonicator. The experiments are carried out in single cylinder four stroke Variable Compression Ratio diesel engine by varying the load using eddy current dynamometer. The experimental results reveal that there is a significant improvement in the performance characteristics like Brake Thermal Efficiency and Brake Specific Fuel Consumption and considerable reduction in the emission constituents like carbon Monoxide (CO) and Unburned Hydrocarbon (HC) and smoke but in turn increase in Nitric oxide (NOx) emissions were observed.


2016 ◽  
pp. 21-28
Author(s):  
Mahendra Kumar Trivedi ◽  
Alice Branton ◽  
Dahryn Trivedi ◽  
Gopal Nayak ◽  
Ragini Singh ◽  
...  

Toluic acid isomers are widely used as a chemical intermediate in manufacturing of dyes, pharmaceuticals, polymer stabilizers, insect repellent and other organic synthesis. The aim of present study was to evaluate the impact of biofield treatment on physical, thermal and spectroscopic properties of ortho isomer of toluic acid (OTA). The OTA sample was divided into two groups, served as control and treated. The treated group received Mr. Trivedi’s biofield treatment. Subsequently, the control and treated samples were evaluated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis/ derivative thermogravimetry (TGA/DTG), Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy. XRD result showed 26.66% decrease in crystallite size in treated OTA sample as compared to control. Furthermore, DSC analysis result showed that latent heat of fusion was considerably reduced by 6.68% in treated OTA sample as compared to control. However, an increase in melting point was observed in treated sample. The melting point of treated OTA sample was found to be 107.96°C as compared to control (105.47°C) sample. Moreover, TGA/ DTG studies showed that Tmax (temperature, at which sample lost its maximum weight) was decreased by 1.21% in treated OTA sample as compared to control. It indicates that vaporisation of treated OTA sample might increase as compared to control. The FT-IR and UV-Vis spectra did not show any significant changes in spectral properties of treated OTA sample as compared to control. These findings suggest that biofield treatment has significantly altered the physical and thermal properties of OTA, which could make it more useful as chemical intermediate.


2020 ◽  
Vol 16 ◽  
Author(s):  
Nimisha Jadon ◽  
Gulzar Ahmad Bhat ◽  
Manoharmayum Vishwanath Sharma ◽  
Harendra Kumar Sharma

Background: The study focuses on the synthesis of chitosan/ Fe2O3 nanocomposite, its characterization and application in methyl orange dye degradation. Methods: The synthesized chitosan/ Fe2O3 nanocomposite was characterized with Powder X-Ray Diffraction, Fourier Transformation Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and UV-Vis Spectroscopy. Results: The characterization showed that the Fe2O3nanoparticles were embedded in the polymer matrix of chitosan. The size of the Fe2O3nanoparticles were less than 10nm and the crystallite size was 1.22 nm.The synthesized chitosan/ Fe2O3nanocomposite was tested for methyl orange degradation using different parameters such as effect of contact time, effect of dose, effect of concentration and effect of pH for the degradation of methyl orange dye in aqueous solution.The Fruendlich, Langmuir and Temkin isotherm studies were also conducted for adsoption of methyl orange on Chitosan/ Fe2O3nanocomposite. Conclusion: The study indicated that the synthesized chitosan/Fe2O3 nanocomposite had the potential of degrading methyl orange dye up to 75.04% under the set condition in this experiment which indicate that Chitosan/ Fe2O3 nanocomposite is a viable option that can be used for the degradation of methyl orange dye.


1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.


Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5970
Author(s):  
Nabil Al-Zaqri ◽  
Mohammed Suleiman ◽  
Anas Al-Ali ◽  
Khaled Alkanad ◽  
Karthik Kumara ◽  
...  

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2–sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.


Polyhedron ◽  
2011 ◽  
Vol 30 (15) ◽  
pp. 2550-2557 ◽  
Author(s):  
Katarzyna Suracka ◽  
Alina Bieńko ◽  
Jerzy Mroziński ◽  
Rafał Kruszyński ◽  
Dariusz Bieńko ◽  
...  

2018 ◽  
Vol 84 (3) ◽  
pp. 30301 ◽  
Author(s):  
Wided Zerguine ◽  
Djamila Abdi ◽  
Farid Habelhames ◽  
Meriem Lakhdari ◽  
Hassina Derbal-Habak ◽  
...  

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.


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