Antibacterial and antibiofilm activities of selenium nanoparticles-antibiotic conjugates against anti-multidrug-resistant bacteria

The crucial demand to overcome the issue of multidrug resistance is required to refine the performance of antibiotics. Such a process can be achieved by fastening them to compatible nanoparticles to obtain effective pharmaceuticals at a low concentration. Thus, selenium nanoparticles (Se NPs) are considered biocompatible agents that are applied to prevent infections resulting from bacterial resistance to multi-antibiotics. The current evaluated the effectiveness of Se NPs and their conjugates with antibiotics such as amikacin (AK), levofloxacin (LEV), and piperacillin (PIP) against Pseudomonas aeruginosa (P. aeruginosa). In addition, the study determined the antibacterial and antibiofilm properties of Se NPs and their conjugates with LEV against urinary tract pathogens such as Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis), P. aeruginosa, and Escherichia coli (E. coli). The result of minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) for eight isolates of P. aeruginosa revealed that the conjugation of Se NPs with AK, LEV, and PIP resulted in a reduction in the concentration of antibiotic-conjugated Se NPs. The concentration was found to be about 10-20 times lower than that of bare antibiotics. The MIC of the Se NPs with LEV (i.e., Se NPs:LEV) for S. aureus, E. faecalis, P. aeruginosa, and E. coli was found to be 1.4:0.5, 0.7:0.25, 22:8, and 11:4 µg/mL, respectively. The results of the half-maximal inhibitory concentration (IC50) demonstrated that Se NPs:LEV conjugate have inhibited 50 % of the mature biofilms of S. aureus, E. faecalis, P. aeruginosa, and E. coli at a concentration of 27.5 ± 10.5, 18.8 ± 3.1, 40.6 ± 10.7, and 21.6 ± 3.3 µg/mL, respectively compared to the control. It has been suggested that the antibiotic-conjugated Se NPs have great potential for biomedical applications. The conjugation of Se NPs with AK, LEV, and PIP increases the antibacterial potency against resistant pathogens at a low concentration.

Lithium-Based Upconversion Nanoparticles for High Performance Perovskite Solar Cells

In this work, we report an easy, efficient method to synthesize high quality lithium-based upconversion nanoparticles (UCNPs) which combine two promising materials (UCNPs and lithium ions) known to enhance the photovoltaic performance of perovskite solar cells (PSCs). Incorporating the synthesized YLiF₄:Yb,Er nanoparticles into the mesoporous layer of the PSCs cells, at a certain doping level, demonstrated a higher power conversion efficiency (PCE) of 19%, additional photocurrent, and a better fill factor (FF) of 82% in comparison to undoped PSCs (PCE = ~16.5%; FF = 71%). The reported results open a new avenue toward efficient PSCs for renewable energy applications.

Tin Complexes Containing an Atenolol Moiety as Photostabilizers for Poly(Vinyl Chloride)

The lifetime of poly(vinyl chloride) (PVC) can be increased through the addition of additives to provide protection against irradiation. Therefore, several new tin complexes containing atenolol moieties were synthesized and their photostabilizing effect on PVC was investigated. Reacting atenolol with a number of tin reagents in boiling methanol provided high yields of tin complexes. PVC was then mixed with the tin complexes at a low concentration, producing polymeric thins films. The films were irradiated with ultraviolet light and the resulting damage was assessed using different analytical and surface morphology techniques. Infrared spectroscopy and weight loss determination indicated that the films incorporating tin complexes incurred less damage and less surface changes compared to the blank film. In particular, the triphenyltin complex was very effective in enhancing the photostability of PVC, and this is due to its high aromaticity (three phenyl rings) compared to other complexes. Such an additive acts as a hydrogen chloride scavenger, radical absorber, and hydroperoxide decomposer.

Protection of Poly(Vinyl Chloride) Films against Photodegradation Using Various Valsartan Tin Complexes

Poly(vinyl chloride) is a common plastic that is widely used in many industrial applications. Poly(vinyl chloride) is mixed with additives to improve its mechanical and physical properties and to enable its use in harsh environments. Herein, to protect poly(vinyl chloride) films against photoirradiation with ultraviolet light, a number of tin complexes containing valsartan were synthesized and their chemical structures were established. Fourier-transform infrared spectroscopy, weight loss, and molecular weight determination showed that the non-desirable changes were lower in the films containing the tin complexes than for the blank polymeric films. Analysis of the surface morphology of the irradiated polymeric materials showed that the films containing additives were less rough than the irradiated blank film. The tin complexes protected the poly(vinyl chloride) films against irradiation, where the complexes with high aromaticity were particularly effective. The additives act as primary and secondary stabilizers that absorb the incident radiation and slowly remit it to the polymeric chain as heat energy over time at a harmless level.

Convenient Synthesis of New Heterocycles Containing the Quinoxaline Ring System

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The aim of the current article was to describe simple procedures for the synthesis of new heterocycles incorporating the quinoxaline moiety using benzene-1,2-diamine and quinoxaline-2,3- dithiol as precursors. Simple synthetic methods are described for the synthesis of new heterocycles using commercially available chemicals. Also, the new compounds were determined using analytical and spectroscopic methods including single X-ray crystal structures. A series of new heterocycles containing the quinoxaline nucleus have been synthesized in good yields using simple and convenient procedures. A process has been described for the synthesis of new heterocycles containing the quinoxaline moiety that might be difficult to synthesize by other routes.

Atomic-Level Microstructure of Efficient Formamidinium-Based Perovskite Solar Cells Stabilized by 5-Ammonium Valeric Acid Iodide Revealed by Multinuclear and Two-Dimensional Solid-State NMR

Chemical doping of inorganic-organic hybrid perovskites is an effective way of improving the performance and operational stability of perovskite solar cells (PSCs). Here we use 5-ammonium valeric acid iodide (AVAI) to chemically stabilize the structure of α-FAPbI₃. Using solid-state MAS NMR, we demonstrate the atomic-level interaction between the molecular modulator and the perovskite lattice and propose a structural model of the stabilized three-dimensional structure, further aided by density functional theory (DFT) calculations. We find that one-step deposition of the perovskite in the presence of AVAI produces highly crystalline films with large, micrometer-sized grains and enhanced charge-carrier lifetimes, as probed by transient absorption spectroscopy. As a result, we achieve greatly enhanced solar cell performance for the optimized AVA-based devices with a maximum power conversion efficiency (PCE) of 18.94%. The devices retain 90% of the initial efficiency after 300 h under continuous white light illumination and maximum-power point-tracking measurement.

Photostabilization of Poly(vinyl chloride) by Organotin(IV) Compounds against Photodegradation

Poly(vinyl chloride) (PVC), a polymer widely used in common household and industrial materials, undergoes photodegradation upon ultraviolet irradiation, leading to undesirable physicochemical properties and a reduced lifetime. In this study, four telmisartan organotin(IV) compounds were tested as photostabilizers against photodegradation. PVC films (40-µm thickness) containing these compounds (0.5 wt%) were irradiated with ultraviolet light at room temperature for up to 300 h. Changes in various polymeric parameters, including the growth of hydroxyl, carbonyl, and alkene functional groups, weight loss, reduction in molecular weight, and appearance of surface irregularities, were investigated to test the efficiency of the photostabilizers. The changes were more noticeable in the blank PVC film than in the films containing the telmisartan organotin(IV) compounds. These results reflect that these compounds effectively inhibit the photodegradation of PVC, possibly by acting as hydrogen chloride and radical scavengers, peroxide decomposers, and primary photostabilizers. The synthesized organotin(IV) complexes could be used as PVC additives to enhance photostability.

The crystal structure of N-(7-(4-fluorobenzylidene)-3-(4-fluorophenyl)-3,3a,4,5,6,7-hexahydro-2H-indazole-2-carbonothioyl)benzamide, C28H23F2N3OS

C28H23F2N3OS, monoclinic, I2/a (no. 15), a = 20.3481(8) Å, b = 10.2647(4) Å, c = 23.6975(11) Å, β = 105.317(5)°, V = 4773.8(4) Å3, Z = 8, R gt(F) = 0.0489, wR ref(F 2) = 0.1543, T = 296(2) K.

5-Methyl-N′-[5-methyl-1-(4-methylphenyl)-1H-1,2,3-triazole-4-carbonyl]-1-(4-methylphenyl)-1H-1,2,3-triazole-4-carbohydrazide, C22H22N8O2

C22H22N8O2, monoclinic, P21/c (no. 14), a = 15.5175(5) Å, b = 7.9715(3) Å, c = 17.3941(5) Å, β = 90.005(3)°, V = 2151.61(12) Å3, Z = 4, R gt(F) = 0.0592, wR ref(F 2) = 0.1780, T = 293(2) K.

Long-Term Effect of Ultraviolet Irradiation on Poly(vinyl chloride) Films Containing Naproxen Diorganotin(IV) Complexes

As poly(vinyl chloride) (PVC) photodegrades with long-term exposure to ultraviolet radiation, it is desirable to develop methods that enhance the photostability of PVC. In this study, new aromatic-rich diorganotin(IV) complexes were tested as photostabilizers in PVC films. The diorganotin(IV) complexes were synthesized in 79-86% yields by reacting excess naproxen with tin(IV) chlorides. PVC films containing 0.5 wt % diorganotin(IV) complexes were irradiated with ultraviolet light for up to 300 h, and changes within the films were monitored using the weight loss and the formation of specific functional groups (hydroxyl, carbonyl, and polyene). In addition, changes in the surface morphologies of the films were investigated. The diorganotin(IV) complexes enhanced the photostability of PVC, as the weight loss and surface roughness were much lower in the films with additives than in the blank film. Notably, the dimethyltin(IV) complex was the most efficient photostabilizer. The polymeric film containing this complex exhibited a morphology of regularly distributed hexagonal pores, with a honeycomb-like structure-possibly due to cross-linking and interactions between the additive and the polymeric chains. Various mechanisms, including direct absorption of ultraviolet irradiation, radical or hydrogen chloride scavenging, and polymer chain coordination, could explain how the diorganotin(IV) complexes stabilize PVC against photodegradation.

Synthesis of Telmisartan Organotin(IV) Complexes and their use as Carbon Dioxide Capture Media

Novel, porous, highly aromatic organotin(IV) frameworks were successfully synthesized by the condensation of telmisartan and an appropriate tin(IV) chloride. The structures of the synthesized organotin(IV) complexes were elucidated by elemental analysis, 1H-, 13C-, and 119Sn-NMR, and FTIR spectroscopy. The surface morphologies of the complexes were inspected by field emission scanning electron microscopy. The synthesized mesoporous organotin(IV) complexes have a Brunauer-Emmett-Teller (BET) surface area of 32.3-130.4 m2·g-1, pore volume of 0.046-0.162 cm3·g-1, and pore size of around 2.4 nm. The tin complexes containing a butyl substituent were more efficient as carbon dioxide storage media than the complexes containing a phenyl substituent. The dibutyltin(IV) complex had the highest BET surface area (SBET = 130.357 m2·g-1), the largest volume (0.162 cm3·g-1), and was the most efficient for carbon dioxide storage (7.1 wt%) at a controlled temperature (323 K) and pressure (50 bars).

Crystal structure of 5-(5-(4-chlorophenyl)-1-phenyl-1H-pyrazol-3-yl)-N-phenyl-2-amine, C23H16ClN5O

C23H16ClN5O, monoclinic, P21/c (no. 14), a = 10.0503(6) Å, b = 17.5265(9) Å, c = 22.8763(16) Å, β = 91.554(6)°, V = 4028.1(4) Å3, Z = 8, R gt(F) = 0.0748, wR ref(F 2) = 0.2274, T = 296(2) K.

Crystal structure of N′-(1-(benzofuran-2-yl)ethylidene)-2-cyanoacetohydrazide, C13H11N3O2

C13H11N3O2, triclinic, P1̄ (no. 2), a = 7.889(2) Å, b = 9.367(3) Å, c = 9.630(3) Å, α = 64.82(3)°, β = 106.507(4)°, γ = 84.57(2), V = 585.1(3) Å3, Z = 2, R gt(F) = 0.0550, wR ref(F 2) = 0.1455, T = 293(2) K.

Perovskite Solar Cells Yielding Reproducible Photovoltage of 1.20 V

High photovoltages and power conversion efficiencies of perovskite solar cells (PSCs) can be realized by controlling the undesired nonradiative charge carrier recombination. Here, we introduce a judicious amount of guanidinium iodide into mixed-cation and mixed-halide perovskite films to suppress the parasitic charge carrier recombination, which enabled the fabrication of >20% efficient and operationally stable PSCs yielding reproducible photovoltage as high as 1.20 V. By introducing guanidinium iodide into the perovskite precursor solution, the bandgap of the resulting absorber material changed minimally; however, the nonradiative recombination diminished considerably as revealed by time-resolved photoluminescence and electroluminescence studies. Furthermore, using capacitance-frequency measurements, we were able to correlate the hysteresis features exhibited by the PSCs with interfacial charge accumulation. This study opens up a path to realize new record efficiencies for PSCs based on guanidinium iodide doped perovskite films.

5-[(4-Chlorophenyl)diazenyl]-2-[5-(4-fluorophenyl)-3-(furan-2-yl)-4,5-dihydro-1H-pyrazol-1-yl]-4-methylthiazole

The title compound, C23H17ClFN5OS, comprises fluorophenyl (A), furanyl (B), pyrazolyl (C), methylthiazoyl (D) and chlorophenyl (E) rings. The B–C–D–E linked ring system is close to planar with the dihedral angles B/C, C/D and D/E being 7.6 (1), 3.4 (1) and 8.4 (1)°, respectively. The fluorophenyl group is almost perpendicular to the pyrazoyl ring, as indicated by an A/C twist angle of 79.4 (1)°. In the crystal, inversion dimers linked by pairs of C—H...S contacts are observed.

N′-[5-Acetyl-3-(4-bromophenyl)-2,3-dihydro-1,3,4-thiadiazol-2-ylidene]-5-(1H-indol-3-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide dimethylformamide monosolvate

The main molecule of the title dimethylformamide monosolvate, C28H20BrN7O2S·C3H7NO, comprises bromophenyl (A), thiadiazolyl (B), pyrazolyl (C), phenyl (D) and indolyl (E) ring systems with twist angles between the planes through neigbouring rings A/B, B/C, C/D and C/E of 33.7 (1), 14.8 (1), 60.7 (2) and 20.9 (1)°, respectively. In the crystal, the molecules are related by c-glide symmetry to form columns parallel to [001] which are linked by intermolecular N—H...O, C—H...O and C—H...Br contacts.

1-(4-Fluorophenyl)-5-methyl-N′-{1-[5-methyl-1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl]ethylidene}-1H-1,2,3-triazole-4-carbohydrazide

The title molecule, C22H21FN8O, comprises fluorophenyl (A), methyltriazolyl (B), methyltriazolyl (C) and tolyl (D) rings. The twist angles between the planes through neighbouring ring pairs A/B, B/C and C/D are 45.0 (1), 9.4 (1) and 43.2 (1)°, respectively. Intermolecular π–π interactions between rings A and C and between B and D propagate the structure in the [010] direction and weak C—H...O interactions also occur.

2-[5-(4-Fluorophenyl)-3-(4-methylphenyl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)thiazole

The title compound, C28H23FN6S, comprises phenyl (A), triazolyl (B), thiazolyl (C), pyrazoyl (D), tolyl (E) and fluorophenyl (F) rings, with twist angles between neighbouring rings pairs A/B, B/C, C/D, D/E and D/F of 64.6 (1), 11.7 (2), 23.5 (2), 8.2 (2) and 73.3 (1)°, respectively. A short intramolecular C—H...N contact and a weak intermolecular C—H...π interaction occur. The crystal chosen for data collection was found to be an inversion twin.

The Morphology and Performance of Poly(Vinyl Chloride) Containing Melamine Schiff Bases against Ultraviolet Light

Five Schiff bases derived from melamine have been used as efficient additives to reduce the process of photodegradation of poly(vinyl chloride) films. The performance of Schiff bases has been investigated using various techniques. Poly(vinyl chloride) films containing Schiff bases were irradiated with ultraviolet light and any changes in their infrared spectra, weight, and the viscosity of their average molecular weight were investigated. In addition, the surface morphology of the films was inspected using a light microscope, atomic force microscopy, and a scanning electron micrograph. The additives enhanced the films resistance against irradiation and the polymeric surface was much smoother in the presence of the Schiff bases compared with the blank film. Schiff bases containing an ortho-hydroxyl group on the aryl rings showed the greatest photostabilization effect, which may possibly have been due to the direct absorption of ultraviolet light. This phenomenon seems to involve the transfer of a proton as well as several intersystem crossing processes.

5-[5-(4-Chlorophenyl)isoxazol-3-yl]-N-phenyl-1,3,4-oxadiazol-2-amine

The title compound, C17H11ClN4O2, consists of chlorophenyl (A), isoxazolyl (B), oxadiazolyl (C) and phenyl (D) rings with twist angles between the planes through neighbouring rings A/B, B/C and C/D of 14.9 (1), 1.8 (1) and 8.9 (1)° respectively. In the crystal, adjacent molecules related by inversion symmetry form columns parallel to the [010] direction through π–π stacking [shortest centroid–centroid separation = 3.6203 (10) Å]; these are cross-linked by N—H...N interactions in the [001] direction.

N′-[5-Acetyl-3-(4-chlorophenyl)-2,3-dihydro-1,3,4-thiadiazol-2-ylidene]-5-(1H-indol-3-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide dimethylformamide monosolvate

In the title solvate, C28H20ClN7O2S·C3H7NO, the main molecule consists of chlorophenyl (A), thiadiazolyl (B), pyrazolyl (C), phenyl (D) and indolyl (E) rings, with twist angles between neighbouring rings A/B, B/C, C/D and D/E of 32.6 (1), 14.8 (1), 60.8 (1) and 20.1 (1)°, respectively. The dimethylformamide solvent molecule accepts an N—H...O hydrogen bond from the indole group. In the extended structure, molecules related by 21 screw axes are stacked in the [001] direction to form columns linked by weak C—H...O interactions.

SEM analysis of the tunable honeycomb structure of irradiated poly(vinyl chloride) films doped with polyphosphate

The fabrication of tunable poly(vinyl chloride) porous films containing polyphosphate as an additive was successful. Irradiation of poly(vinyl chloride) films containing polyphosphate at a low concentration (0.5% by weight) with an ultraviolet light (λmax = 313 nm) for 300 h leads to the formation of a honeycomb like structure. The scanning electron microscopy images, at different magnification power, confirmed the production of the PVC honeycomb-like structure. The morphological images of the polymeric film showed a rough surface and a large number of regularly distributed hexagonal pores. The number of pores increased upon irradiation time and it was maximum after 300 h. The honeycomb structure formation could be due to the regular aggregation of polyphosphate among the polymeric chains, the increase in solution intrinsic viscosity and evaluation of hydrogen chloride gas through dehydrochlorination process.

Crystal structure of N′-(1-(2-hydroxyphenyl)ethylidene)-5-methyl-1-phenyl-1H-1,2,3-triazole-4-carbohydrazide, C18H17N5O2

C18H17N5O2, monoclinic, P21/n (no. 14), a = 20.3702(7) Å, b = 7.3482(2) Å, c = 23.2504(10) Å, β = 106.507(4)°, V = 3336.8(2) Å3, Z = 8, R gt(F) = 0.0571, wR ref(F 2) = 0.1507, T = 296(2) K.

5-[(4-Bromophenyl)diazenyl]-2-{2-[1-(1H-indol-3-yl)ethylidene]hydrazinyl}-4-methylthiazole dimethylformamide hemisolvate

The asymmetric unit of the title compound, 2C20H17BrN6S·C3H7NO, comprises two molecules of the thiazole derivative and one molecule of dimethylformamide (DMF) solvent. The twist angles between the planes through the bromophenyl, methylthiazolyl and indolyl groups are 10.1 (1) and 44.2 (1)°, respectively, for one molecule and 11.3 (1) and 1.6 (1)° for the other. In the crystal, N—H...N hydrogen bonds link four of the main molecules into tetramers. N—H...O bonds involving the DMF solvent molecule also occur.

Fabrication of Novel Ball-Like Polystyrene Films Containing Schiff Base Microspheres as Photostabilizers

Polystyrene films containing a low concentration of three highly aromatic Schiff bases were prepared using the casting method. The polystyrene films were irradiated with ultraviolet light (300 h). The polystyrene infrared spectra, weight loss, molecular weight reduction and the surface morphology were examined upon irradiation. The Schiff bases acted as photostabilizers and reduced the photodegradation of polystyrene films to a significant level in comparison to the blank film. The images recorded of the surface of the miscible polystyrene/Schiff base blends showed novel ball-like microspheres with a diameter of 3.4⁻4.3 µm. The Schiff bases were able to endow excellent protection to polystyrene against ultraviolet irradiation.

5-Methyl-1-(4-methylphenyl)-N′-[1-(thiophen-2-yl)ethylidene]-1H-1,2,3-triazole-4-carbohydrazide

The asymmetric unit comprises a single molecule of C17H17N5OS with twist angles between the planes through the thiophenyl, methyltriazolyl and tolyl groups of 12.3 (1) and 44.9 (1)°, respectively. A possible weak intramolecular hydrogen bond forms between the methyl substituent on the triazole ring and the adjacent carbonyl O atom. In the crystal structure, π–π interactions occur between phenyl rings of pairs of molecules related by inversion symmetry with a centroid–centroid separation of 3.7647 (18) Å. The shortest intermolecular hydrogen bonding contact is a C—H...O interaction that generates inversion dimers.

Insights about the Absence of Rb Cation from the 3D Perovskite Lattice: Effect on the Structural, Morphological, and Photophysical Properties and Photovoltaic Performance

Efficiencies >20% are obtained from the perovskite solar cells (PSCs) employing Cs⁺ and Rb⁺ based perovskite compositions; therefore, it is important to understand the effect of these inorganic cations specifically Rb⁺ on the properties of perovskite structures. Here the influence of Cs⁺ and Rb⁺ is elucidated on the structural, morphological, and photophysical properties of perovskite structures and the photovoltaic performances of resulting PSCs. Structural, photoluminescence (PL), and external quantum efficiency studies establish the incorporation of Cs⁺ (x < 10%) but amply rule out the possibility of Rb-incorporation into the MAPbI₃ (MA = CH₃ NH₃⁺ ) lattice. Moreover, morphological studies and time-resolved PL show that both Cs⁺ and Rb⁺ detrimentally affect the surface coverage of MAPbI₃ layers and charge-carrier dynamics, respectively, by influencing nucleation density and by inducing nonradiative recombination. In addition, differential scanning calorimetry shows that the transition from orthorhombic to tetragonal phase occurring around 160 K requires more thermal energy for the Cs-containing MAPbI₃ systems compared to the pristine MAPbI₃ . Investigation including mixed halide (I/Br) and mixed cation A-cation based compositions further confirms the absence of Rb⁺ from the 3D-perovskite lattice. The fundamental insights gained through this work will be of great significance to further understand highly promising perovskite compositions.

Ethyl 2-anilino-4-methyl-5-[5-methyl-1-(4-methylphenyl)-1H-1,2,3-triazole-4-carbonyl]thiophene-3-carboxylate

The conformation of the title compound, C25H24N4O3S, is influenced by an intramolecular N—H...O hydrogen bond, which generates an S(6) ring. The twist angles between the planes through the toluyl, methyltriazole, thiophene and phenyl rings are 60.1 (1), 33.5 (1) and 39.9 (1)°, respectively. In the crystal, molecules are stacked along the a-axis direction with weak aromatic π–π stacking interactions occurring between the thiophene rings [centroid-to-centroid distance = 3.7285 (15) Å].

5-Methyl-1-(4-methylphenyl)-N′-[1-(1H-pyrrol-2-yl)ethylidene]-1H-1,2,3-triazole-4-carbohydrazide monohydrate

In the title hydrate, C17H18N6O·H2O, the twist angles between the least-squares planes of the pyrolyl/methyltriazolyl/tolyl groups are 11.4 (2) and 7.9 (1)°, respectively. In the crystal, centrosymmetric tetramers (two organic molecules and two water molecules) are linked by N—H...O and O—H...O hydrogen bonds. Weak aromatic π–π stacking interactions between the triazolyl rings [centroid–centroid separation = 3.6422 (10) Å] link the tetramers.

Sodium 1-(4-chlorophenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate

In the title molecular salt, Na+·C10H7ClN3O2 −, the dihedral angles between the planes of adjacent chlorophenyl, methyltriazole and carboxylate groups of the anion are 50.2 (1) and 9.0 (3)°, respectively. The shortest distance between sodium cations is 4.0595 (9) Å. The sodium cation is coordinated by two N atoms and three O atoms, generating layers of ions lying parallel to the bc plane.

Fabrication of ordered honeycomb porous poly(vinyl chloride) thin film doped with a Schiff base and nickel(II) chloride

A modified poly(vinyl chloride) honeycomb thin film containing a low concentration of a thiadiazole Schiff base and nickel(II) chloride was successfully fabricated using the casting process. The surface morphology of the synthesized thin film was investigated using the scanning electronic microscopy. The synthesized poly(vinyl chloride) thin film was found to have a homogeneous surface morphology with a high crystalline nature. The addition of nickel(II) chloride was discovered to be vital for the formation of the honeycomb like structure.

Crystal structure of (E)-N′-(4-methoxybenzylidene)-5-methyl-1-(4-tolyl)-1H-1,2,3-triazole-4-carbohydrazide, C19H19N5O2

C19H19N5O2, triclinic, P1̄ (no. 2), a = 6.6320(3) Å, b = 10.3272(5) Å, c = 13.0832(6) Å, α = 102.751(2)°, β = 96.130(2)°, γ = 103.079(2)°, V = 839.63(7) Å3, Z = 2, R gt = 0.0553, wR ref(F2 ) = 0.1521, T = 100(2) K.

Crystal structure of (E)-3-(3-(5-methyl-1-4-tolyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-4-yl)-1-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)prop-2-en-1-one, C31H26N8O

C31H26N8O, triclinic, P1̄ (no. 2), a = 6.6046(3) Å, b = 15.1056(8) Å, c = 15.2115(8) Å, α = 61.996(2)°, β = 80.390(3)°, γ = 87.579(2)°, V = 1319.97(12) Å3, Z = 2, R int = 0.108, wR(F 2) = 0.143, T = 296(2) K.

Poly(vinyl Chloride) Photostabilization in the Presence of Schiff Bases Containing a Thiadiazole Moiety

Five Schiff bases containing a thiadiazole moiety have been used as poly(vinyl chloride) photostabilizers at low concentrations. The efficiency of Schiff bases as photostabilizers was investigated using various techniques, for example, the changes in poly(vinyl chloride) infrared spectra, molecular weight, chain scission quantum yield, and surface morphology were monitored upon irradiation with an ultraviolet light. Evidently, all the additives used inhibited poly(vinyl chloride) photodegradation at a significant level. The most efficient Schiff base exhibited a high level of aromaticity and contained a hydroxyl group. It seems possible that such photostabilization could be due to the direct absorption of ultraviolet radiation by the additives. In addition, Schiff bases could act as radical scavengers and proton transfer facilitators to stabilize the polymeric materials.

(E)-1-(4-Bromophenyl)-3-[3-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one

In the title compound, C27H20BrN5O, the dihedral angle between the heterocyclic rings is 10.2 (2)°. The phenyl ring bound to the triazole ring is disordered over two orientations in a 0.808 (4):0.192 (4) ratio. In the crystal, C—H...O interactions form chains along [010]. π–π interactions are observed between the phenyl–pyrazolyl unit and the phenylene group of a neighbouring molecule.

Ethyl 1-phenyl-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxylate

The non-H atoms of the title molecule, C19H16N2O2, are almost coplanar (r.m.s. deviation = 0.019 Å), apart from the phenyl group, which is disordered with two components of almost equal occupancy: the dihedral angle between them is 78.9 (3)°. In the crystal, weak C—H...N hydrogen bonds link the molecules into [001] chains and aromatic π–π stacking interactions [shortest centroid–centroid separation = 3.747 (2) Å] form columns parallel to the c-axis direction.

(E)-3-(4-Fluorophenyl)-1-[1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl]prop-2-en-1-one

The asymmetric unit of the title compound, C18H13F2N3O, comprises two molecules with similar conformations. In the crystal, weak C—H...F interactions form chains of molecules and the chains are stacked to form layers parallel to (101).

The Effect of Ultraviolet Irradiation on the Physicochemical Properties of Poly(vinyl Chloride) Films Containing Organotin(IV) Complexes as Photostabilizers

Three organotin(IV) complexes containing ciprofloxacin as a ligand (Ph₃SnL, Me₂SnL₂ and Bu₂SnL₂; 0.5% by weight) were used as additives to inhibit the photodegradation of polyvinyl chloride films (40 µm thickness) upon irradiation with ultraviolet light (λmax = 313 at a light intensity = 7.75 × 10-7 ein dm-3 S-1) at room temperature. The efficiency of organotin(IV) complexes as photostabilizers was determined by monitoring the changes in the weight, growth of specific functional groups (hydroxyl, carbonyl and carbene), viscosity, average molecular weight, chain scission and degree of deterioration of the polymeric films upon irradiation. The results obtained indicated that organotin(IV) complexes stabilized poly(vinyl chloride) and the dimethyltin(IV) complex was the most efficient additive. The surface morphologies of poly(vinyl chloride) films containing organotin(IV) complexes were examined using an atomic force microscope and scanning electron microscopy. These showed that the surface of polymeric films containing organotin(IV) complexes were smoother and less rough, compared to the surface of the blank films. Some mechanisms that explained the role of organotin(IV) complexes in poly(vinyl chloride) photostabilization process were proposed.

(E)-2-Benzoyl-3-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]acrylonitrile

The asymmetric unit of the title compound, C23H15N3OS, consists of two crystallographically independent molecules, which are related by a pseudo-inversion centre. In one molecule, the pyrazolyl ring makes dihedral angles of 35.7 (4), 19.1 (1) and 47.3 (1)°, respectively, with the thiophenyl ring, the attached phenyl ring and the phenyl ring of the benzoyl group. In the second molecule, the corresponding values are 37.4 (1), 16.1 (1) and 48.2 (1)°, respectively. In the crystal, the two independent molecules are linked to each otherviaa π–π interaction between the pyrazolyl rings [centroid–centroid distance = 3.578 (12) Å]. Weak intermolecular C—H...O interactions are also observed. The thiophenyl ring of one molecule is disordered over two orientations, with a refined occupancy ratio of 0.768 (3):0.232 (3).

4-(4-Bromophenyl)-2-(3-(4-chlorophenyl)-5-{3-[5-methyl-1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl]-1-phenyl-1H-pyrazol-4-yl}-4,5-dihydro-1H-pyrazol-1-yl)thiazole

In the title compound, C37H28BrClN8O, the linked chlorophenyl, pyrazolyl and thiazolyl ringss are almost coplanar, with dihedral angles of 0.6 (3)° between the chlorophenyl and pyrazolyl rings and 5.4 (3)° between the pyrazolyl and thiazolyl rings. The dihedral angle between the thiazolyl and bromophenyl rings is 17.5 (2)°. The central pyrazolyl rings subtend a dihedral angle of 67.7 (1)°. In the crystal, π–π and C—H...Br interactions link the molecules to form columns parallel to [010]. The π–π interactions involve partially overlapping nonparallel bromophenyl and tolyl groups.

2-({6-[5-Methyl-1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl]imidazo[2,1-b]thiazol-5-yl}methylidene)hydrazinecarbothioamide dimethylformamide 0.25-solvate

The asymmetric unit of the title solvate, C17H16N8S2·0.25C3H7NO, consists of two C17H16N8S2 molecules and a dimethylformamide molecule disordered about a crystallographic inversion centre. Both triazole molecules feature an intramolecular C—H...N interaction, which generates an S(6) ring in each case. In the crystal, the components are linked by N—H...N and N—H...S hydrogen bonds to form [001] chains, which are cross-linked by weak C—H...O, C—H...N and C—H...S interactions.

Ethyl (Z)-2-[2-(4-methylphenyl)hydrazin-1-ylidene]-3-oxo-3-(thiazol-2-ylamino)propanoate

In the title compound, C15H16N4O3S, the dihedral angle between the aromatic rings is 15.90 (19)°. The molecule features two intramolecular N—H...O hydrogen bonds, which both close S(6) rings. In the crystal, weak C—H...O interactions link the molecules into [010] chains.

Methyl 5-(1-benzofuran-2-yl)isoxazole-3-carboxylate

The title compound, C13H9NO4, is almost planar (r.m.s. deviation = 0.071 Å). In the crystal, weak C—H...O and C—H...N interactions connect the molecules into ribbons propagating parallel to thea-axis direction.

1-[5-Methyl-1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl]ethanone

In the title compound, C12H13N3O, thep-tolyl ring is twisted away from the mean plane (r.m.s. deviation = 0.044 Å) of the rest of the molecule by 50.84 (6)°. In the crystal, molecules are linked by C—H...π interactions, forming zigzag chains propagating in theb-axis direction.

Crystal structure of 3-(2-bromophenyl)-1,1-dimethylthiourea, C9H11BrN2S

C9H11BrN2S, orthorhombic, P212121 (no. 19), a = 7.5187(3) Å, b = 8.0634(3) Å, c = 17.5320(6) Å, V = 1062.90(7) Å3, Z = 4, R gt(F) = 0.0216, wR ref(F 2) = 0.0536, T = 296(2) K.

Crystal structure of 1,1-dimethyl-3-(2-phenylethyl)urea, C11H16N2O

C11H16N2O, orthorhombic, Pbca (no. 61), a = 10.7388(6) Å, b = 9.8449(5) Å, c = 21.1259(14) Å, V = 2233.5(2) Å3, Z = 8, Rgt(F) = 0.0582, wRref(F2) = 0.1795, T = 293 K.