Journal of Applied Spectroscopy最新文献

Five variants of hydroxypyrrolidine-2-one have been synthesized through a solvent-free one-pot reaction employing n-propylamine, isopropylamine, and ethylenediamine with a 2(3H)-furanone derivative. The reaction products demonstrated exceptionally efficient yield and eco-friendliness. Spectroscopic analysis was applied to fully characterize the samples, complementing single-crystal X-ray diffraction analysis and computational outcomes. The single-crystal diffraction of compound 1 confirmed its crystallization in a monoclinic system. The structure demonstrates a significant density of O–H…O interactions between molecules, which is consistent with the findings of the Hirshfeld investigation. The density functional theory (DFT) results and the observed crystalline structure are compared. A notable correlation was identified between the observed and theoretical geometric values. For bioactivity to occur, the most electrophilic site must be near the hydroxyl group linked to the heterocyclic ring, as indicated by the molecule's electrostatic potential. The frontier molecular orbitals were examined to determine the energy disparity between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), indicating significant molecular stability. At a dosage of 3.4 μg/mL, compound 1 exhibited potent anticancer efficacy against breast and colon tumors in the HCT-116 and MCF-7 cell lines, respectively. Moreover, compound 5 exhibited substantial antibacterial efficacy.

Cree 4H-SiC single crystal wafers were studied by high-resolution nondestructive photoluminescence (PL) at room temperature to investigate experimentally near-band-edge (NBE) and stacking fault PL. The contribution of stacking fault PL to the PL spectrum of the original 4H-SiC crystals allowed the intensity ratios of band-to-band, NBE, and stacking fault PL to be evaluated. The experimental PL spectrum of 4H-SiC obeyed a Lorentzian distribution. Electron–phonon interaction led to a significant mutual dependence of the band-to-band, NBE, and stacking fault PL intensities.

IR spectroscopic and photocatalytic studies of thin-film TiO₂–V₂O₅ heterooxide composites obtained by codeposition of TiO₂ and V₂O₅ colloids, chemical deposition of a V₂O₅ shell over TiO₂ particles, and thermal decomposition of ammonium vanadate in the presence of TiO₂ particles have shown that the disordered V₂O₅ phase produced via a pyrolytic synthetic route formed close heterocontacts with titania particles that facilitated charge separation and simultaneously ensured effective accumulation of the photoinduced charges.

The present study reports the petrographical analysis and trap parameter calculation of γ-ray-irradiated limestone sample collected from the Rasmada mines of Chhattisgarh Basin. A limestone sample was collected and preannealed before irradiation and recording of the thermoluminescence (TL) glow curve. The collected limestone sample was then characterized by X-ray diffraction, scanning electron microscopy (SEM), and TL glow curve analysis. The lime-stone sample revealed a cubic structure and its corresponding planes were calculated. SEM images showed a sound morphology and particle-size distribution above the microlevel. The TL glow curve was recorded for various doses of γ-rays from 0.5 to 2 kGy, and the dual peaks were decomposed with a single intense glow curve. The corresponding trap parameters were calculated using a computerized glow curve deconvolution technique. The findings suggest that the investigated limestone sample holds potential for application in gamma radiation dosimetry.

This work focuses on developing and validating an accurate ultra-violet (UV) spectroscopic approach to quantify gepirone hydrochloride for in vitro dissolution studies in its pure drug and pharmaceutical dosage form. The method was designed to be straightforward, cost-effective, efficient, and suitable for routine analysis and quality control in pharmaceutical laboratories. With 0.1N HCl and phosphate buffer(pH-6.8), the gepirone hydrochloride exhibited λ_max at 233 and 235 nm, respectively. The UV spectroscopic method showed excellent linearity with a high correlation coefficient of 0.998 and 0.996 for 0.1N HCl and a phosphate buffer(pH-6.8) in the 2–20 μg/mL concentration range. Beer’s principle was followed in the 2–20 μg/mL concentration range. Precision studies revealed minimal variability, both within and between assay runs, while recovery studies confirmed high accuracy. The method's specificity was validated by the absence of interference from excipients, and its robustness was confirmed through small deliberate variations in experimental conditions, with no significant impact on performance. This UV spectroscopy method presents a practical, highly accurate, and reproducible approach for analyzing gepirone hydrochloride in pharmaceutical formulations, ensuring both regulatory compliance and the maintenance of drug quality.

A series of europium Eu³⁺-doped orange-red emitting phosphors were synthesized through a high-temperature solidphase reaction using NaSr₄(BO₃)₃ as the host in an atmosphere of air. The effects of calcination temperature and the contents of boric acid and Eu³⁺ on the photoluminescent properties of the as-prepared phosphors were investigated. In particular, the addition of boric acid in excess of the stoichiometric ratio could significantly improve the singlephase purity of the host. Meanwhile, the synthesis times for the phosphors were also reduced. The crystal phases and fluorescent properties of NaSr_4–x(BO₃)₃:xEu³⁺ were characterized using X-ray powder diffraction analysis and a fluorescence spectrophotometer, respectively. The luminescent intensity of the phosphor was highest at the calcination temperature of 880°C for 3 h, which was the optimum condition for forming single-phase NaSr₄(BO₃)₃ hosts. All prepared NaSr₄(BO₃)₃ phosphors belonged to the cubic crystal system. The maximum excitation wavelength was 392 nm. The main emission peaks were observed at 591 nm (orange light) and 615 nm (red light), which corresponded to the ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions of Eu³⁺, respectively. Furthermore, NaSr_3.92(BO₃)₃:0.04Eu³⁺ reached the maximum intensity of the main emission peaks, and the red-emitting performance was outstanding. The ratio (R/O) of the intensities of the emission peaks of red and orange lights could be affected by changes in the contents of Eu³⁺, so as to enrich and simplify the strategies for improving the red-emitting light purity. This provides a basis for the development of high-brightness and high-color-purity red-emitting phosphors for LED chips excited by nearultraviolet light.

The extensive use of tricyclazole pesticide poses a serious threat to humans and the ecosystem, thus there is an urgent need to develop a sensitive and rapid detection method. In this study, a novel β-cyclodextrin (β-CD)/phenolphthalein (PP) supramolecular probe was designed for the determination of tricyclazole in water. Tricyclazole and β-CD formed a 1:1 inclusion complex in aqueous solution at 25°C by using UV-visible spectra according to the Benesi–Hildebrand method. Phenolphthalein and tricyclazole compete to enter the hydrophobic cavity of β-CD due to host–guest recognition, causing changes in absorbance. Based on this principle, the β-CD/PP supramolecular probe exhibits a wide detection scope (1.0 × 10^–5–3.0 × 10^–4 M) and moderate detection limits of 1.22 × 10^–5 M for tricyclazole detection under the optimal conditions. The optimal geometries for the host and guest molecules were determined by density functional theory (DFT) calculations. Molecular docking analysis demonstrated the optimal PP and tricyclazole orientation inside the cavity of β-CD, and revealed the inherent driving forces of the inclusion reaction between β-CD and the guest molecules. Gibbs free energy change (∆G) values indicate that β-CD/tricyclazole is more stable than β-CD/PP inclusion complex. In addition, the β-CD/PP probe exhibited a high selective performance toward tricyclazole in water, and the β-CD/PP probe can be applied to detect tricyclazole in real water samples with satisfactory recoveries (93.8–101.8%). This simple strategy establishes the potential for determining other pesticides by host–guest recognition that match the β-CD hydrophobic cavity.

The dynamic vacuum-assisted thermal annealing method was employed to prepare active layers of the perovskite CsPbI₃, which is highly suitable for solar cells due to its high stability and optimal band gap (1.7 eV). Application of this method improved the active layer structure due to the reduction of defect states and nanopores and the increase of crystalline grain size. The dynamic vacuum-assisted thermal annealing method effectively reduced the trap-state density and suppressed recombination due to the faster removal of dimethylformamide (DMF). The optical and photoelectric properties of perovskite solar cells (PSCs) fabricated using dynamic vacuum-assisted thermal annealing method were comparatively analyzed versus ambient-condition processing. As a result, the open-circuit voltage (V_oc) of PSCs prepared by the vacuum-assisted method at low temperatures increased from 1.08 to 1.16 V. Also, the power conversion efficiency of the active layers improved from 16.5 to 18.8%.

We have shown that the discoloration of photochromic poly(vinyl alcohol)–tungstophosphoric acid (PVA–TPA) nanocomposite films and PVA–TPA films containing glycerol (PVA–TPA–GL) colored by UV irradiation can be greatly accelerated by increasing the concentration of GL in the films and the ambient relative humidity. This study resolves the issues of polymer–heteropolyacid nanocomposites associated with their slow bleaching and, thus, makes them potentially applicable as new functional materials for inkless and erasable printing, anti-counterfeiting, sensors, smart windows.

Dapagliflozin and Vildagliptin are type 2 antidiabetic drugs in which Dapagliflozin is a highly selective sodium-glucose cotransporter-2 inhibitor, and Vildagliptin functions as a dipeptidyl peptidase-4 (CD26) inhibitor. This research article proposes a specific tandem spectroscopy approach verified for the assessment of Dapagliflozin and Vildagliptin in their individual and combined pharmaceutical formulations. Method A (absorption correction), where the absorption maximum for Dapagliflozin was 223 nm, also showed absorbance at 276 nm, while the absorption maxima for vildagliptin occur at the same wavelength as the solvent peak, the detection wavelength was thus selected at 223 nm with a zero absorbance at 276 nm. The developed technique exhibited good linearity, ranging from 4–36 μg/mL for Dapagliflozin as well as 40–360 μg/mL for Vildagliptin, exhibiting a high degree of correlation (R² = 0.9964) for Dapagliflozin and (R² = 0.9991) for Vildagliptin. Method B (double-point standardization method), where Vildagliptin shows absorption maxima in the end UV region, thus, for avoiding interference with solvent peaks, the peak of Vildagliptin was shifted to the visible region by using bromocresol green. Ethanol was used as a solvent. The absorption maxima of Dapagliflozin and Vildagliptin were found to be 278 and 622 nm, respectively. The developed method showed good linearity, ranging from 20–52 μg/mL for Dapagliflozin as well as 200–520 μg/mL for Vildagliptin, and it exhibited a high degree of correlation (R²= 0.9989) for Dapagliflozin and (R²= 0.9996) Vildagliptin. Both methods exhibited good linearity, accuracy, and precision, with a low percent relative standard deviation, and they both demonstrated better recovery and reproducibility. A sensitivity test was performed by calculating the LOD and LOQ.