Phosphorus, Sulfur, and Silicon and the Related Elements最新文献

Thiosemicarbazone metal complexes are intriguing molecules with a variety of applications in several fields, including the pharmaceutical sector, analytical chemistry, and textile industries. Here, we designed and synthesized 12 transition metal complexes based on thiosemicarbazone as a tridendate group and azo moiety as a chromophore part, in addition to evaluating their color strength and fastness properties. The tridentate ligand derivatives of 5-(m-tolyldiazenyl)salicylaldehyde thiosemicarbazone reacted with four transition metal salts (copper, cobalt, nickel, and iron salts) in refluxing alkaline ethanol to afford the corresponding thiosemicarbazone complexes. The ligands behaved as double-deprotonated tridentate ligands that connected to the transition metal ions through the deprotonation of phenolic-OH and thiol-SH, as well as the azomethine nitrogen atom, to generate fused five- and six-membered heterocycle rings. The obtained metal complexes were characterized by elemental analyses, atomic absorption, IR, and UV–Vis spectra. The color strength and fastness properties of the printed fabrics were tested, showing good to excellent properties.

The effect of phosphorus on the catalytic performance of molybdenum carbide for the reverse water-gas shift (RWGS) reaction was studied for the first time. It was found that the catalytic activity and selectivity of the P-doped molybdenum carbide catalysts were greatly related to their P/Mo molar ratios within a narrow range (0–0.1). It was obvious that increasing P/Mo molar ratio led to a decreased activity, but can effectively enhance selectivity. The P-doped molybdenum carbide with a P/Mo molar ratio of 0.05 was proposed to be more excellent than other P-doped molybdenum carbides in terms of both activity and selectivity, which was attributed to its higher oxophilicity and weaker affinity toward CO.

Here we report the synthesis and anticancer activities of fourteen novel imidazo[1,2-a]pyridine derivatives (6a-6n) containing S-alkyl/aryl moiety. The target compounds were obtained via a six-step synthetic route. 1-(4-Aminophenyl)ethan-1-one was the starting material. In the last step, 2-chloro-N-[4-(imidazo[1,2-a]pyridin-2-yl)phenyl]acetamide (5) was allowed to react with various aliphatic/aromatic thiol derivatives, affording the final compounds 6a-6n. The cytotoxicity of the compounds was evaluated against A549 (human non-small cell lung cancer), C6 (rat glioma), MCF-7 (human breast carcinoma) and HepG2 (human liver carcinoma) tumor cells and NIH/3T3 (mouse embryonic fibroblast cells) healthy cells. First step MTT assay reported that compounds 6a, 6d, 6e and 6i exhibited antiproliferative activity against all tested tumor lines. Second step BrdU cell proliferation assay and flow cytometric analysis revealed that compounds 6d and 6i inhibited DNA synthesis on HepG2 cell line time-dependently by apoptotic pathway. Molecular docking study of compounds 6d and 6i with caspase-3 and caspase-9 revealed their binding interactions with the enzyme’s active site, confirming the experimental findings.

The current research reports the synthesis of a library of thiosemicarbazones (3-16) through a two-step chemical transformation. All the synthesized derivatives were purified and fully characterized through mass spectrometry, NMR spectroscopy (¹H-, and ¹³C-NMR), and IR spectroscopy. All the members of the synthesized library were found to be new except compound 8. The synthesized library was screened for its inhibition potential against the urease enzyme. Almost all the compounds exhibited potent activity with the IC₅₀ = 5.3 ± 0.8 − 15.5 ± 0.6 µM in comparison to the thiourea and acetohydroxamic acid used as standard (IC₅₀ = 21.1 ± 0.2, 20.5 ± 0.4 µM). While significant activity was exhibited by compounds 14 and 15 with the IC₅₀ = 23.6 ± 0.6 and 27.3 ± 1.2 µM. Furthermore, kinetic studies were carried out to determine the inhibition mode and molecular docking was employed to recognize the ligand-enzyme interactions. Thereby, the docking results are well in the direction of the in vitro results. Compounds ((E)-N-(2,5-dichlorophenyl)-2-(4-fluorobenzylidene)hydrazine-1-carbothioamide (3) and (E)-2-(2-chlorobenzylidene)-N-(2-fluorophenyl) hydrazinecarbothioamide (5) were identified as the most potent inhibitors of urease by both the in vitro and in silico studies.

Three quinoline carbonothioate compounds were synthesized using o-fluoroaniline and ethyl 2-methylacetoacetate as starting materials via multi-steps. The structures of three compounds were confirmed using ¹H NMR and HRMS. The structure of O-ethyl S-(8-fluoro-2,3-dimethylquinolin-4-yl) carbonothioate (3a) was further determined through X-ray single-crystal diffraction. Single-crystal X-ray diffraction analysis indicated that compound 3a crystallizes in the monoclinic space group C2/c, with unit cell parameters: a = 14.3284(6) Å, b = 19.2857(8) Å, c = 10.3990(5) Å, β = 108.1220(10)°, V = 2731.0(2) ų. In addition, the physicochemical properties of compound 3a were calculated and discussed using molecular electrostatic potential, frontier molecular orbital and Hirshfeld surface analysis. The antifungal activity of the three compounds was evaluated at 50 μg/mL, with compound 3b exhibiting good activity (75.8%) against R. solani.

The research article reports the synthesis and structural study of the optimized geometry of selenium (Se) bearing 24- and 28- membered macrocyclic Schiff bases, L a H 2, L b H 2 and their reactions with zinc metal ion. The reactions of the macrocyclic Schiff bases with ZnCl₂ in 1:2 molar ratios result in the formation of bimetallic Zn(II) complexes having molecular composition [Se{(CH₂)₂N = CPh(4-CH₃-C₆H₂O) PhC = O}₂ · Zn₂Cl₂], (1) and [Se{(CH₂)₃N = CPh(4-CH₃-C₆H₂O)PhC = O}₂ · Zn₂Cl₂], (2). Moreover, as confirmed by various physico-chemical techniques such as elemental analysis, UV–Vis, FTIR,¹H NMR, and mass spectrometry, the proligands underwent partial hydrolytic cleavage at one of the C = N positions and behave like hexadentate (N₂O₄) ligands binding to two Zn(II) ions via bridging through the O_phenolic atoms, which results in a square pyramidal geometry around Zn(II) with the chlorine atom occupying axial positions. Further, following density functional study, the stable optimized configuration of the Schiff bases L a H 2 and L b H 2 is found to adopt bowl shape geometry. Conversely, in molecular docking studies, the synthesized complex 1 exhibits a significantly stronger binding affinity (−8.7 kcal/mol) to the spike protein of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) as compared to the common coronavirus disease 2019 (COVID-19) treatment drugs such as chloroquine, hydroxychloroquine, and remdesivir with activity percentage showing more than 20% overall effectiveness than remdesivir and thus indicating its potential for COVID-19 therapeutics.

Tris(hydroxymethyl)phosphine oxide, (HOCH₂)₃PO (THPO), is recognized as an efficient flame-retardant polyol and a derivative of PH₃ – an environment-friendly, halogen-free source for phosphorus compounds and polymers. Synthesis and industrial production of THPO are based on straightforward oxidation of tris(hydroxymethyl)phosphine, (HOCH₂)₃P (THP), or neutralized tetrakis(hydroxymethyl)phosphonium chloride (THPC), or sulfate (THPS), by air/O₂ or H₂O₂. In alkaline aqueous media, THP is oxidized by water with liberation of H₂. As an alcohol, THPO readily reacts with isocyanates, epoxides, aziridines, and carboxylic acid derivatives, and is widely used as crosslinker or chain-extender to produce flame-retardant polyurethanes, polyethers, polyesters, and composite materials. Similarly, with compounds containing E–Cl bonds (E = P, Si, and S), THPO forms a variety of flame-retardant P/E-compounds or polymers. Condensation of THPO with phenols proceeds via cleavage of a P–C bond of THPO and liberation of CH₂O that leads to flame-retardant THPO-phenol resins. With functionalized alkyl halides, THPO forms tris(alkoxymethyl)phosphine oxide monomers containing, for example, pendant allyl, propargyl, or silane groups. Halogenation of THPO leads to tris(chloromethyl)phosphine oxide, (ClCH₂)₃PO, or tris(bromomethyl)phosphine oxide, (BrCH₂)₃PO, useful for syntheses of multifunctional organophosphorus compounds, for example, tris(aminomethyl)phosphine oxide, (NH₂CH₂)₃PO, and phosphorus-containing podands. Similar to THPO, tris(hydroxymethyl)phosphine sulfide, (HOCH₂)₃PS, is used in preparation of flame-retardant components for polymers, and, in synthesis of asymmetric phosphorus compounds.

A phosphorus-containing polymer with very high thermo-oxidative stability was synthesized for the first time by addition of silver nitrate to tricyanophosphine (P(CN)₃). By optimizing the reaction time and silver nitrate concentration to a 1:1 molar ratio, a new polycyanophosphate [p(CP)] was formed as the primary phosphorus-containing product over the competing species, P(CN)₃. The reactions and products were monitored by FT-IR, ICP-OES, NMR, and XPS spectroscopic techniques, which indicated a complicated oxidation reaction that converted the P(III) precursor species to P(V) polyphosphate species with pendant cyano- and isocyano- moieties. The p(CP) resin was found to contain a high (17.6 at.%) amount of phosphorus by ICP-OES, which contributed to its excellent thermo-oxidative resistance with a high char yield of over 60 wt.% at 1000 °C (1273 K) in air, indicating that the material could be particularly useful for high-temperature applications.

The effect of substituents of various natures at boron atoms in different positions of the carborane cage on the CH-acidity of carborane derivatives and the electron-withdrawing effect of C-carboranyl groups is considered using ¹H NMR spectroscopy data.

One of the most serious threats to human health is the increasing prevalence of drug-resistant pathogens. The development of new antibiotics capable of combating drug resistance is critical. In various bacteria and plant species, 4-aminobenzoic acid (PABA) is produced and used as a substrate for folate generation. In this study, a new series of PABA analogs were synthesized and evaluated for their antimicrobial activity. Thirteen novel compounds were prepared by linking PABA hydrazide to sulfonate esters via a hydrazone bridge (4a–m). The structures of these compounds were characterized by ¹H and ¹³C NMR and FT-IR spectroscopy as well as by LC-MS. Following structural characterization, all compounds were tested for their antimicrobial activity against Staphylococcus aureus (ATCC 29213), Enterococcus faecium (ATCC 19434), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Candida albicans (ATCC 10231) strains. Four compounds were found to have moderate antimicrobial activity against the P. aeruginosa strain. These compounds, including 4e, 4f, 4g, and 4m, containing a hydrazide-hydrazone sulfonate functionality, showed the best MIC value of 64 μg/mL. In addition, synergistic effects of ascorbic acid, salicylic acid, and N-acetyl cysteine (NAC) with synthesized compounds were also investigated. It was observed that the combination of compounds 4f and 4g with NAC showed antipseudomonal activity with MIC values of 32 μg/mL and 16 μg/mL, respectively, against the P. aeuriginosa strain. The antimicrobial activity of 4f and 4g was enhanced by two folds in combination with NAC. Our findings in this study can be crucial for the development of new potent antimicrobial agents.