Search Results (168)

Background: Transition metal complexes incorporating fluorinated counter anions represent a significant class of compounds with broad applications in industry, pharmaceuticals, and biomedicine. These fluorinated anions are known to enhance the solubility, stability, and reactivity of the complexes, thereby expanding their functional utility in various chemical and biological contexts. Methods: A set of metal(II) complexes of the general formula [MPy₆][B(C₆F₅)₄]₂ where (Py = pyridine, M = Mn (1), Fe (2), Co (3), Ni (4), Cu (5), Zn (6)) have been synthesized by direct reaction of metal halides and pyridine in the presence of Ag[B(C₆F₅)₄]. The complexes were characterized using different techniques to assure their purity, such as elemental analysis (EA), electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA), ultraviolet–visible (UV–Vis) spectroscopy, ¹¹B-NMR, ¹H-NMR, and FT-IR spectroscopy. The antimicrobial and antifungal properties against different types of bacteria and fungi were studied for all prepared complexes. Results: The synthesized complexes exhibited broad-spectrum antimicrobial activity, demonstrating variable efficacy compared to the reference antibiotic, oxytetracycline (positive control). Notably, complex 6 displayed exceptional antibacterial activity against Streptococcus pyogenes, with a minimum inhibitory concentration (MIC) of 4 µg/mL, outperforming the control (MIC = 8 µg/mL). Complexes 1, 2, and 4 showed promising activity against Shigella flexneri, Klebsiella pneumoniae, and Streptococcus pyogenes, each with MIC values of 8 µg/mL. Conversely, the lowest activity (MIC = 512 µg/mL) was observed for complexes 3, 5, and 6 against Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, respectively. Regarding antifungal properties, complexes 5 and 6 demonstrated the highest activity against Candida albicans, with MIC values of 8 µg/mL, equivalent to that of the positive control, fluconazole. Density functional theory (DFT) calculations confirmed an overall octahedral coordination geometry for all complexes, with tetragonal distortions identified in complexes 3, 4, and 5. Full article

This work proposes a systematic study of different computational schemes for fluorine Nuclear Magnetic Resonance (¹⁹F NMR) chemical shifts, with special emphasis placed on the basis set issue. This study encompasses two stages of calculation, namely, the development of the computational schemes for the geometry optimization of fluorine compounds and the NMR chemical shift calculations. In both stages, the performance of different density functional theory functionals is considered against the method of coupled-cluster singles and doubles (CCSD), with the latter representing a theoretical reference in this work. This exchange-correlation functional study is accompanied with a basis set study in both stages of calculation. Basis sets of different families, sizes, and valence-splitting levels are considered. Various locally dense basis sets (LDBSs) are proposed for the calculation of ¹⁹F NMR chemical shifts, and their performance is assessed by comparison of the calculated chemical shifts with both theoretical and experimental reference data. Overall, the pcS-3/pcS-2 LDBS scheme is recommended as the most balanced locally dense basis set scheme for fluorine chemical shift calculations. Full article

After reviewing the state of the art of the fluorination of inorganic solid electrolytes, an application of gas/solid fluorination is given and how it can be processed. Garnet-type oxide has been chosen. These oxides with an ideal structure of chemical formula A₃B₂(XO₄)₃ are mainly known for their magnetic and dielectric properties. Certain garnets may have a high enough Li⁺ ionic conductivity to be used as solid electrolyte of lithium ion battery. The surface of LLZO may be changed in contact with the moisture and CO₂ present in the atmosphere that results in a change of the conductivity at the interface of the solid. LiOH and/or lithium carbonate are formed at the surface of the garnet particles. In order to allow for handling and storage under normal conditions of this solid electrolyte, surface fluorination was performed using elemental fluorine. When controlled using mild conditions (temperature lower or equal to 200 °C, either in static or dynamic mode), the addition of fluorine atoms to LLZO with Li_6,4Al_0,2La₃Zr₂O₁₂ composition is limited to the surface, forming a covering layer of lithium fluoride LiF. The effect of the fluorination was evidenced by IR, Raman, and NMR spectroscopies. If present in the pristine LLZO powder, then the carbonate groups disappear. More interestingly, contrary to the pristine LLZO, the contents of these groups are drastically reduced even after storage in air up to 45 days when the powder is covered with the LiF layer. Surface fluorination could be applied to other solid electrolytes that are air sensitive. Full article

Main-chain conjugated and non-conjugated polyelectrolytes are an important class of materials that have many technological applications ranging from fire-retardant materials to carbon-nanotube composites, nonlinear optical materials, electrochromic materials for smart windows, and optical sensors for biomolecules. Here, we describe a series of poly(pyridinium salt)s-fluorene containing 9,9-bis(4-aminophenyl)fluorene moieties with various organic counterions that were synthesized using ring-transmutation polymerization and metathesis reactions, which are non-conjugated polyelectrolytes. Their chemical structures were characterized by Fourier transform infrared (FTIR), proton (¹H) and fluorine 19 (¹⁹F) nuclear magnetic resonance (NMR) spectrometers, and elemental analysis. They exhibited polyelectrolytic behavior in dimethyl sulfoxide. Their lyotropic liquid-crystalline phases were examined by polarizing optical microscopy (POM) and small angle X-ray scattering (SAXS) studies. Their emission spectra exhibited a positive solvatochromism on changing the polarity of solvents. They emitted greenish-yellow lights in polar organic solvents. They formed aggregates in polar aprotic and protic solvents with the addition of water (v/v, 0–90%), whose λ_em peaks were blue shifted. Full article

Acute pneumonia is frequently accompanied by immune suppression, particularly affecting T-cell subsets, such as CD4⁺, CD4⁺CD25⁺, and CD4⁺CD25⁺FoxP3⁺, which are critical for immune regulation. This study evaluates the immunomodulatory potential of a novel fluorinated piperazine-based aminophosphonate, complexed with β-cyclodextrin ((o-Fph)PPhβCD), comparing it with the clinically approved agent Polyoxidonium (PO) in a rat model of oleic acid-induced acute pneumonia. Flow cytometric analysis revealed that (o-Fph)PPhβCD significantly restored CD4⁺ and CD4⁺CD25⁺ T-cell levels and induced a sustained reduction in regulatory CD4⁺CD25⁺FoxP3⁺ cells, suggesting enhanced effector immune activity. While PO provided early immunorestorative effects, (o-Fph)PPhβCD exerted a more prolonged response, which was particularly evident by day 14. Structural confirmation of the inclusion complex was achieved through IR and NMR spectroscopy. These findings highlight (o-Fph)PPhβCD as a promising immunotherapeutic candidate that is capable of rebalancing immune cell populations and supporting host defense mechanisms during acute pulmonary inflammation. Full article

We report on the preparation and characterization of a new family of hydrogen-bonded nematogenic liquid crystalline dimers. The dimers are supramolecular complexes that consist of a benzoic acid derivative, acting as the proton donor, featuring a spacer with seven methylene groups and a terminal decyloxy chain, paired with an azopyridine derivative as the proton acceptor. The latter was either fluorinated or nonfluorinated with variable alkoxy chain length. The formation of a hydrogen bond between the individual components was confirmed using FTIR and ¹H NMR spectroscopy. All supramolecules were investigated for their liquid crystalline behaviour via a polarized optical microscope (POM) and differential scanning calorimetry (DSC). All materials exhibit enantiotropic nematic phases as confirmed by X-ray diffraction (XRD) and POM investigations. The nematic phase range depends strongly on the degree and position of fluorine atoms. Additionally, the supramolecules demonstrated a rapid and reversible transition between the liquid crystal phase and the isotropic liquid state because of trans-cis photoisomerization upon light irradiation. Therefore, this study presents a straightforward approach to design photo-responsive nematic materials, which could be of interest for nonlinear optics applications. Full article

Usnetic acid is a dibenzofuran-2-ylacetic acid that can be obtained by alkaline degradation of a secondary lichen metabolite—usnic acid. In the present paper, the product of the reaction of usnetic acid with a mild fluorinating agent, Selectfluor^®, was obtained. The structure of the product was proved by a set of physical methods, including ¹H, ¹³C, ¹⁹F NMR, HMBC, HSQC, HRMS and IR spectroscopy. Full article

Fluorinated pyrethroids, such as cyfluthrin and cyhalothrin, are more effective insecticides due to their enhanced stability and lipophilicity. However, they pose greater risks to non-target organisms. Their persistence in the environment and accumulation in tissues can lead to increased toxicity and ecological concerns. This study investigates the biodegradation of the fluorinated pyrethroids β-cyfluthrin (BCF) and λ-cyhalothrin (LCH) using a newly isolated Bacillus sp. MFK14 from a garden soil microbial consortium. Initial screening using ¹⁹F NMR analysis showed that the microbial consortium degraded both pyrethroids, leading to the isolation of Bacillus sp. MFK14. Subsequent GC-MS analysis revealed various degradation intermediates in both pyrethroids after incubation with Bacillus sp. MFK14. Notably, Bacillus sp. MFK14 completely degraded β-cyfluthrin and λ-cyhalothrin within 48 h at 30 °C. Fluoride ions from β-cyfluthrin and trifluoroacetic acid (TFA) from λ-cyhalothrin were detected as the end-products by ¹⁹F NMR analysis of the aqueous fraction. The pathway of the degradation was proposed for both the pyrethroids indicating shared biodegradation pathways despite different fluorinations. Inhibition studies with 1-ABT suggested the involvement of bacterial cytochrome P450 (CYP) enzymes in their biodegradation. The CYPome of Bacillus sp. MFK14 includes 23 CYP variants that showed significant sequence similarity to known bacterial CYPs, suggesting potential roles in pyrethroid biodegradation and environmental persistence. These findings highlight the potential for bioremediation of fluorinated pesticides, offering an environmentally sustainable approach to mitigate their ecological impact. Full article

A new poly(azomethine) with improved solubility was successfully prepared by the polycondensation of terephthalaldehyde and 2,2-Bis[4-(4-aminophenoxy)phenyl]-hexafluoropropane (4-BDAF) under green chemistry conditions. This new polymer containing hexafluoroisopropylidene was compared with a polymer containing isopropylidenediphenyl to study the influence of the presence of fluorine atoms on the properties of the polymer. Both were characterized by nuclear magnetic resonance (NMR), their molecular weight was measured by gel permeation chromatography (GPC), and their morphology was studied by X-ray diffraction (XRD). The two polymers obtained were soluble in most polar aprotic solvents and even in less polar solvents, which are practical and easily accessible solvents. Their thermal properties were determined by a thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). These two new polymers showed high resistance to thermal decomposition up to 490 °C, with a glass transition temperature (Tg) of 180 °C. The photophysical properties were studied by UV/Visible absorption. The polymers were doped and then deposited on cellulose filaments, an approach that made it possible to produce self-supporting conductive composites thanks to their mechanical properties. The topography of the resulting materials was characterized at submicron scales before estimating their electronic conductivity and gap energy by diffuse reflection spectroscopy. Full article

In this study, we developed a novel theranostic nanomedicine formulation that integrates multimodal imaging with controlled drug release in reactive oxygen species (ROS)-rich microenvironments. A fluorinated oxalate compound (FOC) was synthesized through a one-step condensation reaction between 1,1,1,3,3,3-hexafluoro-2-propanol and oxalyl chloride, characterized by ¹H, ¹³C, and ¹⁹F NMR spectroscopy. The FOC and luminophore-incorporated nanomedicine formulations reacted rapidly with hydrogen peroxide via the peroxyoxalate chemiluminescence (POCL) mechanism, producing strong chemiluminescence and inducing a notable 19-fold increase in ratiometric ¹⁹F NMR signal upon conversion to fluorinated alcohol (FAH), demonstrating promising potential for high-contrast ¹⁹F MRI in deep tissue. Following ROS stimulation, the chemical conversion from hydrophobic FOC to hydrophilic FAH led to the degradation of the nanomedicines, facilitating payload release. In vitro experiments with A-431 cancer cells under hypoxic conditions confirmed ROS-responsive drug release, evidenced by enhanced fluorescence from model luminophores. Additionally, doxorubicin-loaded FOC nanomedicines reduced cell viability to 32% under hypoxia while remaining non-toxic in normoxic conditions. These results indicate that FOC-based nanomedicine formulations provide a promising platform for combined chemiluminescence and ¹⁹F MRI with targeted therapeutic efficacy in ROS-rich inflammatory and cancerous tissues. Full article

ATP analogues are essential tools in enzymology and structural biology, but the structural and functional implications of their chemical modifications on nucleotide-binding proteins are often underappreciated. To address this, we evaluated a panel of ATP analogues, focusing on thiosubstituted and fluorinated molecules, using the AAA+ ATPase p97 as a benchmark system. Hydrolysis stability and impact on protein conformation, binding modes, and kinetics of enzymatic catalysis were assessed by protein-detected methyl NMR and ligand-detected ¹⁹F NMR in solution, as well as ³¹P solid-state NMR of nucleotides within protein sediments. ATPγS and AMP-PNP emerged as the most suitable analogues for preserving pre-hydrolysis states over extended periods, despite undergoing gradual hydrolysis. In contrast, both AMP-PCP and α/β-thiosubstituted analogues failed to induce native protein conformations in p97. Notably, we demonstrate a novel real-time NMR setup to explore the effect of nucleotide mixtures on cooperativity and the regulation of enzymes. Additionally, aromatic fluorine TROSY-based ¹⁹F NMR shows promise for direct ligand detection in solution, even in the context of large macromolecular complexes. These findings provide critical guidance for selecting ATP analogues in functional and structural studies of nucleotide-binding proteins. Full article

Cathinone and its synthetic derivatives belong to organic compounds with narcotic properties. Their structural diversity and massive illegal use create the need to develop new analytical methods for their identification in different matrices. NMR spectroscopy is one of the most versatile methods for identifying the structure of organic substances. However, its use could sometimes be very difficult and time-consuming due to the complexity of NMR spectra, as well as the technical limitations of measurements. In such cases, molecular modeling serves as a good supporting technique for interpreting ambiguous spectral data. Theoretical prediction of NMR spectra includes calculation of nuclear magnetic shieldings and sometimes also indirect spin–spin coupling constants (SSCC). The quality of theoretical prediction is strongly dependent on the choice of the theory level. In the current study, cathinone and its 12 fluorinated derivatives were selected for gauge-including atomic orbital (GIAO) NMR calculations using Hartree–Fock (HF) and 28 density functionals combined with 6-311++G** basis set to find the optimal level of theory for ¹H, ¹³C, and ¹⁹F chemical shifts modeling. All calculations were performed in the gas phase, and solutions were modeled with a polarized-continuum model (PCM) and solvation model based on density (SMD). The results were critically compared with available experimental data. Full article

Fragment-based drug discovery is a powerful approach in drug discovery, applicable to a wide range of targets. This method enables the discovery of potent compounds that can modulate target functions, starting from fragment compounds that bind weakly to the targets. While biochemical, biophysical, and cell-based assays are commonly used to identify fragments, ¹⁹F-NMR spectroscopy has emerged as a powerful tool for exploring interactions between biomolecules and ligands. Because fluorine atoms are not naturally present in biological systems, ¹⁹F-NMR serves as a sensitive method for fragment screening against diverse targets. Herein, we reviewed the applications of ¹⁹F-NMR in fragment screening, highlighting its effectiveness in identifying fragments that bind weakly to various targets such as proteins and RNA. The accumulated evidence suggests that ¹⁹F-NMR will continue to be a crucial tool in drug discovery. Full article

New haloaminopyrazole derivatives differing in the number of pyrazole nuclei 4a–f and 5a–e, respectively, were synthesized and characterized by ¹H-NMR, ¹³C-NMR, IR, UV-Vis, and elemental analysis. The single-crystal X-ray diffraction method was used to describe compounds 4a and 5d. When tested on normal NCTC fibroblasts in vitro, the newly synthesized derivatives were shown to be non-cytotoxic at a dosage of 25 μg/mL. Two compounds 4a and 5d showed a high degree of biocompatibility. From the two series of compounds tested on HEp-2 human cervical carcinoma cells, compound 5d showed a more pronounced antiproliferative effect. Gram-positive strains of Staphylococcus aureus ATCC25923, Enterococcus faecalis ATCC29212, Gram-negative strains of Pseudomonas aeruginosa ATCC27853, and strains of Escherichia coli ATCC25922 were used to test the newly synthesized compounds antibacterial and antibiofilm properties. Among the studied pyrazole compounds, 2 compounds 4a and 5a with fluorine content on the phenyl ring and 4 compounds 4b, 4e, 4f, and 5b with chlorine content on the phenyl ring were noted, which proved to be the most active compared with the two reference drugs, metronidazole and nitrofurantoin. The six compounds showed a broad spectrum of action against all four tested bacterial strains, the most active being compound 4b, with a chlorine atom in the “4” position of the phenyl nucleus and a MIC of 460 μg/mL. Compounds 4a and 5a showed the best antibiofilm activity against the bacterial strain Staphylococcus aureus ATCC25923, with an MBIC of 230 μg/mL. Full article

Fluorinated organic compounds have demonstrated remarkable utility in medicinal chemistry due to their enhanced metabolic stability and potent therapeutic efficacy. Several examples exist of fluorinated non-steroidal anti-inflammatory drugs (NSAIDs), including diflunisal, flurbiprofen, and trifluoromethylated pyrazoles celecoxib and mavacoxib. These trifluoromethylated pyrazoles, which are most commonly constructed through the cyclocondensation of a trifluorinated 1,3-dicarbonyl and an aryl hydrazine, are also found in numerous other drug candidates. Here, we interrogate the effects of solvents and the presence of Brønsted or Lewis acid catalysts on catalyzing this process. We highlight the utility of benchtop ¹⁹F NMR spectroscopy in enabling the real-time quantification of reaction progress and the identification of fluorinated species present in crude reaction mixtures without the need for cost-prohibitive deuterated solvents. Ultimately, we find that the reaction solvent has the greatest impact on the rate and product yield, and also found that the relationship between the keto-enol equilibrium of the dicarbonyl starting material pyrazole formation rate is highly solvent-dependent. More broadly, we describe the optimization of the yield and kinetics of trifluoromethylpyrazole formation in the synthesis of celecoxib and mavacoxib, which is made possible through high-throughput reaction screening on benchtop NMR. Full article