Search Results (1,437)

Background: Theophylline, which is biologically important and found in tea, coffee, and cocoa beans, can be synthesized chemically or by direct extraction and concentration from natural sources. Theophylline derivatives have garnered attention in recent years for their potential therapeutic effects on Mycobacterium tuberculosis, antihistaminic, anti-inflammatory, and anticancer. Also, trifluoromethyl (CF₃) group has also been widely used in drug and agrochemical design. Methods: In this study, a series of new theophylline derivatives containing substituted trifluoromethyl and trifluoromethoxy groups were synthesized. The structures of these new compounds were confirmed by NMR, FT-IR, and elemental analyses. Additionally, the anticancer activities of the molecules were analyzed against VEGFR-2, CYP P450, and estrogen receptor by molecular docking method. Furthermore, in vitro biological effects of the compounds were comprehensively evaluated in cancer (A549 and HeLa) and normal (BEAS-2B) cells. Cell viability was assessed by MTT assay, and selectivity index (SI) values were calculated to determine tumor-specific toxicity. Results: N(7)-substituted theophyllines were prepared by the reaction of 1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione (theophylline) and trifluoromethyl substituted benzyl halide compounds. The synthesized N(7)-substituted theophyllines were obtained as white powder in high yield. The structure of synthesized compounds was confirmed by various spectroscopic techniques such as ¹H, ¹³C, ¹⁹F NMR, and FT-IR spectroscopy, and elemental analysis. The highest interaction was recorded as −5.69 kcal/mol for 3-CF₃ substituted against VEGFR-2 structure while the best binding affinity was determined for 4-OCF₃ substituted with −6.69 kcal/mol against Human Cytochrome P450 with in silico analysis. The in vitro anticancer activities of the molecules were also evaluated against A549 and HeLa cells, and displayed considerably higher cytotoxicity with 2-CF₃, 3-CF_3, and 4-CF₃ substituted molecules in Hela and A549 cell line. To elucidate the molecular mechanism, apoptosis-related gene expression changes were analyzed by RT-qPCR in A549 and HeLa cells treated with compound 2-CF₃. Significant upregulation of pro-apoptotic markers and downregulation of anti-apoptotic genes were observed. Consistently, ELISA-based quantification confirmed increased protein levels of Caspase-3, BAX, and Cytochrome C, and decreased BCL-2, validating the apoptotic mechanism at the protein level. Also, the antibacterial and antibiofilm activity details of the molecules were evaluated against DNA Gyrase, and SarA crystal structures by molecular docking method. The highest interaction was recorded as −5.56 kcal/mol for 2-CF₃ substituted with H-bonds with Asn46, Val71, Asp73, and Thr165 against DNA Gyrase crystal structure while 3-CF₃ substituted has the best binding affinity against SarA. The in vitro antimicrobial effects of the molecules were also evaluated. Conclusions: The synthesized molecules may provide insight into the development of potential therapeutic agents to the increasing antimicrobial resistance and biofilm-forming capacity of microorganisms. Additionally, compound 2-CF₃ substituted exhibited promising and selective anticancer activity through apoptosis induction, supported by gene and protein level evidence. Full article

Single crystals of the layered EuRECuTe₃ series with RE = Nd, Sm, Tb and Dy are obtained for the first time, completing the series of studies on quaternary tellurides synthesized using the halide flux method. These compounds crystallize in the orthorhombic space group Pnma (no. 62) with unit cell parameters ranging from a = 11.5634(7) Å, b = 4.3792(3) Å and c = 14.3781(9) Å for EuNdCuTe₃ to a = 11.2695(7) Å, b = 4.3178(3) Å and c = 14.3304(9) Å for EuDyCuTe₃. The influence of prismatic polyhedra [EuTe₆₊₁]⁷⁻ structural units on the stabilization of 3d framework composed by 2d layered fragments [RECuTe₃]²⁻, which have a key role in the interlayer interaction, is established. A comparative analysis of structural and magnetic properties dependence on the rare-earth element radius r_i(RE³⁺) in the EuRECuTe₃ series (RE = Sc, Y, Nd–Lu) is carried out. The structural contraction, including decrease in degree of tetrahedral polyhedra distortion, bond lengths shortening and unit cell volume shrinking with increasing r_i(RE³⁺), is established. It is shown that the structural alternation leads to transition from ferromagnetic to ferrimagnetic ordering. It was established that changes in the cationic sublattice have a more significant impact on structural transitions in the series of quaternary tellurides than changes in the anionic sublattice. The electronic structure and elastic and dynamic properties were estimated using ab initio calculations. The exfoliation energy for each compound is obtained by estimation of monolayer ground state energy as a result of structure relaxation. The symmetry and structural properties of monolayer EuRECuTe₃ (RE = Nd, Sm, Tb, Dy) compound are established and the orthorhombic symmetry is obtained with layer group pm2_1b. Full article

It was demonstrated that various defects can be induced in halide crystals by irradiation with swift heavy ions. Here, we irradiated barium fluoride (BaF₂) single crystals with 220 MeV xenon ions at room temperature and performed stepwise thermal annealing up to the temperature of 825 K to study the kinetics of ion-induced defects at different temperatures. Optical spectroscopy was utilized for the measurement of the wide range of absorption spectra from NIR to VUV. A sharp decrease in the F₂ absorption peak was observed for the samples annealed in the temperature range of 400–450 K. This result can be explained by their recombination with anion interstitials during thermal decay of the complex hole centers. The mobile interstitials, those did not recombine with the F₂ centers, increase the absorption peaks in the 9–10 eV region, which can be associated with interstitial aggregates. Full article

This study deciphers the anionic modulation mechanism of halide ions (F⁻/Cl⁻) in cobalt-based hydroxides for oxygen evolution reaction (OER). Phase-pure Co(OH)₂, Co(OH)F, and Co₂(OH)₃Cl were fabricated via substrate-independent hydrothermal synthesis to eliminate conductive support interference. Electrocatalytic evaluation on glassy carbon electrodes demonstrates fluoride’s superior regulatory capability over chloride. X-ray photoelectron spectroscopy (XPS) analyses revealed that F⁻ incorporation induces charge redistribution through Co → F electron transfer, optimizing the electronic configuration via ligand effects. F⁻ incorporation simultaneously guided the anisotropic growth of 1D nanorods and reduced surface energy, thereby enhancing the wettability of Co(OH)F. The engineered Co(OH)F catalyst delivers exceptional OER performance: 318 mV overpotential at 10 mA/cm² in 1 M KOH with 94% current retention over 20 h operation. This study provides a synthetic strategy for preparing pure-phase Co(OH)F and compares halide ions’ effects on enhancing OER activity through electronic structure modulation and morphological control of basic cobalt salts. Full article

Electrochemical deposition of silicon is considered a promising alternative to conventional high-temperature and high-emission methods of silicon production. This review analyzes the current state of research on electrolyte systems used for silicon electrodeposition, with a particular focus on their potential for industrial-scale application. These systems are evaluated based on key characteristics relevant to such implementation, including silicon precursor solubility, electrical conductivity, applicable current density, and behavior under process conditions. The study evaluates fluoride-based, chloride-based, mixed halide, and organic electrolyte systems based on key criteria, including conductivity, chemical stability, silicon precursor solubility, temperature range, and ease of product purification. Fluoride-based melts offer high current densities (up to 2 A/cm²) and effective SiO₂ dissolution but operate at high temperatures (550–1300 °C) and suffer from hygroscopicity. Chloride systems exhibit lower operating temperatures (300–1000 °C) and better water solubility but lack compatibility with common silicon sources. Mixed fluoride–chloride electrolytes emerge as the most promising option, combining high performance with improved practicality; they operate at 600–850 °C and current densities up to ~1.5 A/cm². Additional focus is placed on the impact of substrate materials and on unresolved questions related to reaction reversibility, kinetic mechanisms, and the influence of electrolyte composition. The review concludes that further fundamental studies are needed to optimize electrolyte design and enable the transition from laboratory-scale research to industrial implementation. Full article

Nickel-catalyzed cyanation of aryl halides has emerged as a powerful and sustainable method for the synthesis of aryl nitriles—valuable motifs widely found in pharmaceuticals, agrochemicals, and functional materials. Compared to traditional cyanation methods that involve harsh conditions and toxic reagents, nickel catalysis enables mild, efficient, and versatile transformations. This review systematically summarizes recent advances in this field, categorized by different cyanide sources, including metal cyanides (NaCN, KCN, Zn(CN)₂, K₄[Fe(CN)₆]) and non-metal or organic cyanide sources (e.g., MeCN, nitriles, BrCN, CO₂/NH₃). Key developments in catalyst systems, ligand design, mechanistic insights, and green chemistry aspects are highlighted. Remaining challenges and future directions are also discussed. Full article

Structure–property relationships in imidazolium-based hybrid Sb(III) chlorides provide critical guidance for designing high-performance materials. Three zero-dimensional metal halides, namely, [C₃mmim]₂SbCl₅ (1, [C₃mmim]⁺ = 1-propyl-2,3-dimethylimidazolium), [C₅mmim]₂SbCl₅ (2, [C₅mmim]⁺ = 1-pentyl-2,3-dimethylimidazolium), and [C₅mim]₂SbCl₅ (3, [C₅mim]⁺ = 1-pentyl-3-methylimidazolium), are synthesized by ionothermal methods. These compounds exhibit markedly distinctly photophysical properties at their optimal excitation wavelengths. Structural analyses reveal that elongated alkyl chains in compounds 2 and 3 increase Sb–Sb distances compared to that in 1, effectively isolating [SbCl₅]²⁻ units, suppressing inter-center energy transfer, and reducing non-radiative transitions, thereby enhancing the photoluminescence quantum yield (PLQY). Furthermore, methyl substitution at the C2-position of the imidazolium ring in compounds 1 and 2 induces asymmetric coordination environments around the [SbCl₅]²⁻ emission centers, leading to pronounced structural distortion. This distortion promotes non-radiative decay pathways and diminishes luminescent efficiency. Furthermore, temperature-dependent spectroscopy analysis and fitting of the Huang–Rhys factor (S) reveal significant electron–phonon coupling in compounds 1–3, which effectively promotes the formation of self-trapped excitons (STEs). However, compound 1 exhibits extremely high S, which significantly enhances phonon-mediated non-radiative decay and ultimately reduces its PLQY. Overall, compound 3 has the highest PLQYs. Full article

Halide perovskite-based memristors are promising neuromorphic devices due to their unique ion migration and interface tunability, yet their conduction mechanisms remain unclear, causing stability and performance issues. Here, we engineer interstitial Ag⁺ ions within a quasi-two-dimensional (quasi-2D) halide perovskite ((C₆H₅C₂H₄NH₃)₂Cs_n−1Pb_nI_3n+1) to enhance device stability and controllability. The introduced Ag⁺ ions occupy organic interlayers, forming thermodynamically stable structures and introducing deep-level energy states without structural distortion, which do not act as non-radiative recombination centers, but instead serve as efficient charge trapping centers that stabilize intermediate resistance states and facilitate controlled filament evolution during resistive switching. This modification also leads to enhanced electron transparency near the Fermi level, contributing to improved charge transport dynamics and device performance. Under external electric fields, these Ag⁺ ions act as mobile ionic species, facilitating controlled filament formation and stable resistive switching. The resulting devices demonstrate exceptional performance, featuring an ultrahigh on/off ratio (∼10⁸) and low operating voltages (∼0.31 V), surpassing existing benchmarks. Our findings highlight the dual role of Ag⁺ ions in structural stabilization and conduction modulation, providing a robust approach for high-performance perovskite memristor engineering. Full article

Cd-based perovskite materials have the advantages of high emission efficiency and tunable emission, as well as broad application prospects in the field of optoelectronics. However, achieving multimode dynamic luminescence under UV light excitation in a single system is a great challenge. Here, we successfully prepared Sb³⁺/Pb²⁺ co-doped Cs₇Cd₃Br₁₃ crystals by a simple hydrothermal method. Tunable emission from orange to white and then to blue, covering the wavelength range between 370 and 800 nm, was achieved by varying the doping concentration of Pb²⁺ ions in Cs₇Cd₃Br₁₃:0.5%Sb³⁺. Temperature-dependent photoluminescence (PL) spectra and density functional theory (DFT) calculations confirm that the wide-band white-light emission of Cs₇Cd₃Br₁₃: Sb³⁺/Pb²⁺ crystal comes from the first self-trapped exciton (STE1) of undoped Cs₇Cd₃Br₁₃ intrinsic capture state and the emission of free excitons (FEs) and STE2 induced by the confining effect and the Jahn–Teller effect by Pb²⁺ incorporation, as well as the Sb triplet self-trapped exciton (STE3). More specifically, the samples with the best co-doped ratio exhibit significant excitation-wavelength-dependent luminescence characteristics and can realize the conversion of the emission color from white and blue to orange. Based on the tunable emission characteristics of three emission colors, the material has good prospects in encryption and anti-counterfeiting applications. This work provides a new strategy for the application of Cd-based halides in the field of anti-counterfeiting. Full article

The toxicity of lead in conventional perovskites and their inherent chemical instability impede the commercialization of perovskite-based optoelectronics. Therefore, it is vital to develop chemically stable and environmentally friendly Pb-free alternatives. Recently, zero-dimensional (0D) all-inorganic Cs₂ZnCl₄ doped with Sn(II) has emerged as a promising candidate, exhibiting superior chemical robustness, minimal biotoxicity, and exceptional optoelectronic properties. In this work, pressure effects on structure and optical properties in Sn(II)-doped all-inorganic zero-dimensional halide perovskite are investigated both experimentally and theoretically. The structure–property relationship of Sn(II)-doped Cs₂ZnCl₄ is studied using high-pressure techniques. Piezochromism, accompanied by a remarkable change in emission color from orange/red and green to orange/yellow, was obtained from 1 atm to 22.5 GPa. Angle dispersive synchrotron X-ray diffraction (ADXRD) patterns and Raman spectra manifest that the material underwent an isostructural phase transition followed by amorphization with increasing pressure. The piezochromism and band gap engineering originate from the pressure-induced lattice compression and isostructural phase transition. This work advances STE emission studies and provides a robust strategy to boost emission efficiency and to construct multifunctional materials with piezochromism in environmentally friendly perovskites, thus facilitating diverse future applications. Full article

Metal halide perovskites have appeared as a promising semiconductor for high-efficiency and low-cost photovoltaic technologies. However, their performance and long-term stability are dramatically constrained by defects at the surface and grain boundaries of polycrystalline perovskite films formed during the processing. Herein, we propose a defect-targeted passivation strategy using 2-chlorocinnamic acid (2-Cl) to simultaneously enhance the efficiency and stability of perovskite solar cells (PSCs). The crystallization kinetics, film morphology, and optical and electronic properties of the used formamidinium–cesium lead halide (FA_0.85Cs_0.15Pb(I_0.95Br_0.05)₃, FACs) absorber were modulated and systematically investigated by various characterizations. Mechanistically, the carbonyl group in 2-Cl coordinates with undercoordinated Pb²⁺ ions, while the chlorine atom forms Pb–Cl bonds, effectively passivating the surface and interfacial defects. The optimized FACs perovskite film was incorporated into inverted (p-i-n) PSCs with a typical architecture of ITO/NiO_x/PTAA/Al₂O₃/FACs/PEAI/PCBM/BCP/Ag. The optimal device delivers a champion power conversion efficiency (PCE) of 22.58% with an open-circuit voltage of 1.14 V and a fill factor of 82.8%. Furthermore, the unencapsulated devices retain 90% of their initial efficiency after storage in ambient air for 30 days and 83% of their original PCE after stress under 1 sun illumination with maximum power point tracking at 50 °C in a N₂ environment, demonstrating the practical potential of dual-site molecular passivation for durable perovskite photovoltaics. Full article

In this paper, various Ga₂O₃ films, including amorphous Ga₂O₃ films, β-Ga₂O₃, and α-Ga₂O₃ epitaxial films, have been nitridated and converted to single-crystalline GaN layers on the surface. Although the original Ga₂O₃ films are different, all the converted GaN layers exhibit the (002) preferred orientation and the porous morphologies. The ~200 µm GaN thick films have been grown on the nitridated Ga₂O₃ films using the halide vapor phase epitaxy (HVPE) method. Raman analysis indicates that all the HVPE-GaN films grown on nitridated Ga₂O₃ films are almost stress-free. An obvious GaN porous layer/Ga₂O₃ structure has been observed in the interface between GaN thick films and sapphire substrates. The porous GaN layers can be used as promising templates for the preparation of free-standing GaN substrates. Full article

Inorganic halide perovskites have garnered significant attention as promising candidates for photovoltaic and optoelectronic applications, owing to their enhanced thermal and chemical stability relative to hybrid perovskite materials. This review synthesizes recent progress in vapor-phase deposition methodologies, such as co-evaporation, close space sublimation (CSS), continuous flash sublimation (CFS), and chemical vapor deposition (CVD), which enable the precise modulation of film composition and morphology. Advances in material systems, including the stabilization of CsPbI₂Br, the introduction of tin-doped phases, and the investigation of lead-free double perovskites like Cs₂AgSbI₆ and Cs₂AgBiCl₆, are critically evaluated with respect to their impact on device performance. The incorporation of these materials into photovoltaic devices and tandem configurations is explored, with particular emphasis on improvements in power conversion efficiency and operational durability. Furthermore, interface engineering approaches tailored to vacuum-deposited films—such as defect passivation and energy-level alignment—are examined in detail. The potential for scalable manufacturing is assessed through simulation analyses, throughput modeling, and pilot-scale demonstrations, underscoring the feasibility of industrial-scale production. By offering a comprehensive overview of these advancements, this review provides valuable perspectives on the current landscape and prospective trajectories of vapor-deposited inorganic perovskite technologies. Full article

In the last decades, numerous approaches have been explored for the cross-coupling of biaryl building blocks depending on the presence of boron sources. In fact, these changes have been catalyzed by transition metal complexes. This review focuses on the progress of the last decade in transition metal-catalyzed C–X borylation and direct C–H borylation, with emphasis on nickel-catalyzed C–H borylation, as effective and affordable protocols for the borylation of aryl substrates. In addition, Suzuki-type cross-coupling by activation of C–H, C–C, or C–N bonds is also reported. This study then offers an overview of recent advances for the synthesis of bi- and multi-aryls found in synthetic molecular complexes and natural products using the transition metal-catalyzed one-pot Miyaura-type C–X and C–H borylation–Suzuki coupling sequence. Full article

Recent research on the design and synthesis of new and upgraded materials for secondary batteries is growing to fulfill future energy demands around the globe. Herein, by using DFT calculations, the thermodynamic and electrochemical properties of Na/Na⁺@C₁₂ complexes and then halogens (X⁻ = Br⁻, Cl⁻, and F⁻) as counter anions are studied for the enhancement of Na-ion battery cell voltage and overall performance. Isolated C₁₂ nanorings showed a lower cell voltage (−1.32 V), which was significantly increased after adsorption with halide anions as counter anions. Adsorption of halides increased the Gibbs free energy, which in turn resulted in higher cell voltage. Cell voltage increased with the increasing electronegativity of the halide anion. The Gibbs free energy of Br⁻@C₁₂ was −52.36 kcal·mol⁻¹, corresponding to a desirable cell voltage of 2.27 V, making it suitable for use as an anode in sodium-ion batteries. The estimated cell voltage of these considered complexes ensures the effective use of these complexes in sodium-ion secondary batteries. Full article