Ronald Nelson

Developing sustainable paradigms for nanomaterial synthesis is essential to reduce the environmental impact of conventional chemical routes. Herein, we report a green, phytochemically mediated synthesis of MnFe₂O₄NPs using aqueous grapefruit (Citrus paradisi) peel extracts. The bioflavonoid and polyphenolic constituents functioned as dual-functional biogenic reducing and stabilizing agents. FTIR analysis verified spinel lattice metal–oxygen bonds and surface-bound biogenic groups, while SEM imaging revealed the surface morphology and structural aggregation of the nanoparticles. Once integrated into an electroanalytical platform (MnFe₂O₄NPs/GCE), the modified interface exhibited robust electrocatalytic activity toward sulfite oxidation in an acetate buffer (pH = 4.0). Mixed-valence dynamics (Mn²⁺/Mn³⁺ and Fe²⁺/Fe³⁺) significantly amplified anodic currents and lowered the kinetic overpotential. Under optimized chronoamperometric conditions, the sensor demonstrated a wide linear range (1–100 μM, r = 0.999), a low detection limit (LOD = 0.045 μM), a limit of quantification (LOQ = 0.136 μM) and excellent selectivity against co-existing ionic and organic interferents. This study provides a simple, eco-friendly, and technically robust strategy for fabricating high-performance electrochemical platforms for food and environmental monitoring.

Antimicrobial resistance (AMR) remains a major threat to modern medicine, fueled by the excessive use of antibiotics and the spread of multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). In this study, we designed and synthesized a series of 2-aryl-4-aminoquinazoline derivatives bearing an aminoalkylimidazole linker, combining two pharmacophoric motifs associated with antimicrobial activity. Starting from anthranilamide, the compounds were prepared in three straightforward steps, affording good yields and high purity. Their structures were confirmed by FT-IR spectroscopy, ¹H and ¹³C nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS). Biological evaluation showed that series 5 exhibited strong selectivity toward S. aureus, with compounds 5c and 5d displaying minimum inhibitory concentrations (MICs) between 2.2 and 4.4 µM. No significant activity was observed against other tested strains. Cytotoxicity assays in HepG2 cells revealed moderate to low inhibition. Molecular docking indicated preferential binding to dihydrofolate reductase (DHFR) and relevant interactions with topoisomerase IV, resembling reference inhibitors. ADME analysis predicted favourable absorption, blood–brain barrier permeability, and compliance with Lipinski’s rules.

This work focuses on the sustainable green synthesis of magnetic iron oxide nanoparticles (Fe₃O₄NPs) using bioreductants derived from orange peel extracts for application in the efficient oxygen evolution reactions (OER). The synthesized catalysts were characterized using X-ray diffraction analysis, field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV–visible spectroscopy. The Fe₃O₄NPs exhibit a well-defined spherical morphology with a larger Brunauer–Emmett–Teller surface area and a significant electrochemically active surface area. The green synthesis using orange peel extracts leads to an excellent electrocatalytic activity of the apparent spherical Fe₃O₄NPs (diameter of 9.62 ± 0.07 nm), which is explored for OER in an alkaline medium (1.0 M KOH) using linear-sweep and cyclic voltammetry techniques. These nanoparticles achieved a benchmark current density of 10 mA cm⁻² at a low overpotential of 0.3 V versus RHE, along with notable durability and stability. The outstanding OER electrocatalytic activity is attributed to their unique morphology, which offers large surface area and an ideal porous structure that enhances the adsorption and activation of reactive species. Furthermore, structural defects within the nanoparticles facilitate efficient electron transfer and migration of these species, further accelerating the OER process.

The synthesis of (E)-1-(1-benzyl-5-methyl-1H-1,2,3-triazol-4-yl)-3-phenyl-2-propen-1-one derivatives was carried out in two steps, using benzylic chloride derivatives as starting material. The structural determination of intermediates and final products was performed by spectroscopic methods: infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry (IR, NMR, and MS). In vitro evaluation of cytotoxic activity on adherent and non-adherent cells showed that triazole chalcones exhibited significant activity against three of the five cell lines studied: non-Hodgkin lymphoma U937, glioblastoma multiform tumor T98G, and gallbladder cancer cells Gb-d1. In contrast, the cytotoxic activity observed for cervical cancer HeLa and gallbladder adenocarcinoma G-415 was considerably lower. Additionally, in the cell lines where activity was observed, some compounds demonstrated an In vitro inhibitory effect superior to that of the control, paclitaxel. Molecular docking studies revealed specific interactions between the synthesized ligands and therapeutic targets in various cell lines. In U937 cells, compounds 4a and 4c exhibited significant inhibition of vascular endothelial growth factor receptor (VEGFR) kinase, correlating with their biological activity. This effect was attributed to favorable interactions with key residues in the binding site. In T98G cells, compounds 4r and 4w showed affinity for transglutaminase 2 (TG2) protein, driven by their ability to form hydrophobic interactions. In Gb-d1 cells, compounds 4l and 4p exhibited favorable interactions with mitogen-activated protein kinase (MEK) protein, similar to those observed with the known inhibitor selumetinib. In HeLa cells, compounds 4h and 4g showed activity against dihydrofolate reductase (DHFR) protein, driven by hydrogen bonding interactions and favorable aromatic ring orientations. On the other hand, compounds 4b and 4t exhibited no activity, likely due to unfavorable interactions related to halogen substitutions in the aromatic rings.

The Atacama Desert's extreme UV radiation impacts photovoltaic devices, reducing silicon solar cell efficiency through overheating and photodegradation. To address this, we integrated a europium complex derived from 1-(diphenylphosphoryl)-3-isoquinolinecarboxylic acid into a polyvinyl butyral (PVB) matrix, forming a luminescent down-shifting layer (LDSL) that converts UV radiation into visible light. This LDSL improves light harvesting and mitigates UV-induced degradation. After LDSL application, photovoltaic analysis of a c-Si cell showed significant enhancements: short-circuit current density (J_sc) increased from 28.82 to 34.69 mA cm⁻², open-circuit voltage (V_oc) rose from 630.6 to 635.7 mV, and the fill factor (FF) remained stable. Incident photon-to-current efficiency (IPCE) curves indicated better performance, particularly in the UVA range, with overall cell efficiency improving from 14.10% to 16.62% at higher Eu complex concentrations. Electrochemical impedance spectroscopy (EIS) revealed that the Eu complex improved charge transfer, reducing recombination losses. This approach demonstrates significant potential for enhancing solar cell performance in high-irradiance environments like the Atacama Desert.

The combination of a Pd(0) source and a phosphoramidite ligand promotes a formal allylic cross‐coupling between alkylidenecyclopropanes (ACPs) and boronic acids to yield synthetically appealing 1,1‐disubstituted alkenes. Remarkably, the reaction proceeds both under neutral and basic conditions, and works with both aryl‐ and alkenylboronic acids. DFT calculations suggest that the reaction entails a C−C activation/protonation mechanism instead of a hydropalladation pathway, which has been frequently proposed for other metal‐promoted hydrofunctionalizations of ACPs.

Approximately 4% of women of reproductive age are estimated to suffer from premenstrual dysphoric disorder (PMDD), a condition likely underdiagnosed due to various biases, suggesting that actual prevalence may be higher. Addressing this, a novel electrochemical sensor was developed using a screen-printed electrode of reduced graphene oxide modified with a Cu(II) triazole complex, Cu(L^NO2)₂/rGO/SPCE. This sensor aims to determine levels of serotonin and 17β-estradiol rapidly, and simultaneously, key analytes implicated in PMDD. The method demonstrated high sensitivity for both analytes, achieving sensitivity levels of 0.064 μA/μmol L⁻¹ for serotonin and 0.055 μA/μmol L⁻¹ for 17β-estradiol, with a linear detection range of 2 to 42 μmol L⁻¹. Detection limits were 42 nmol L⁻¹ for serotonin and 53 nmol L⁻¹ for estrogen. The sensor also exhibited high stability and selectivity against common interferents found in biological fluids. It was successfully used to measure serotonin and 17β-estradiol in human serum and urine, with recovery percentages within the expected ranges. This demonstrates that the sensor proposed in this work holds significant potential to contribute not only to the accurate diagnosis of such disorders but also to their treatment. We hope that this research will pave the way for the development of devices that have a positive impact on the quality of life of women suffering from multisystem diseases caused by hormonal malfunctions.

This manuscript details a comprehensive investigation into the synthesis, structural characterization, thermal stability, and optical properties of nickel-containing hybrid perovskites, namely CH₃NH₃NiCl₃, CsNiCl₃, and CH₃NH₃NiBrCl₂. The focal point of this study is to unravel the intricate crystal structures, thermal behaviors, and optical characteristics of these materials, thereby elucidating their potential application in energy conversion and storage technologies. X-ray powder diffraction measurements confirm that CH₃NH₃NiCl₃ adopts a crystal structure within the Cmcm space group, while CsNiCl₃ is organized in the P6₃/mmc space group, as reported previously. Such structural diversity underscores the complex nature of these perovskites and their potential for tailored applications. Thermal analysis further reveals the stability of CH₃NH₃NiCl₃ and CH₃NH₃NiBrCl₂, which begin to decompose at 260 °C and 295 °C, respectively. The optical absorption properties of these perovskites studied by UV-VIS-NIR spectroscopy revealed the bands characteristic of Ni²⁺ ions in an octahedral environment. Notably, these absorption bands exhibit subtle shifts upon bromide substitution, suggesting that optical properties can be finely tuned through halide modification. Such tunability is paramount for the design and development of materials with specific optical requirements. By offering a detailed examination of these properties, the study lays the groundwork for future advancements in material science, particularly in the development of innovative materials for sustainable energy technologies.