Reduced Graphene Oxide-Supported Nickel(II)-Bis(1,10-Phenanthroline) Complex as a Highly Active Electrocatalyst for Ethanol Oxidation Reaction

In situ synthesis of a UIO-66-NH2@Ti3C2 composite for advanced electrochemical detection of acetaminophen

Acetaminophen (AP) is a widely used analgesic and antipyretic drug, but its excessive use poses health risks and contributes to environmental contamination. In response to the need for rapid, accurate, and cost-effective detection methods, we developed a highly sensitive and selective electrochemical sensor for AP. The sensor was based on a composite of UIO-66-NH2 (UN) and an MXene (Ti3C2). UIO-66-NH2 was in situ synthesized onto the MXene via a one-step hydrothermal process with a varying MXene content, followed by calcination at 300 °C under an argon (Ar) flow. This treatment induced the formation of TiO2 on the MXene surface and increased the interlayer spacing, which enhanced its electrochemical performance. The resulting UN@Ti3C2-C electrode exhibited remarkable electrochemical activity due to the high surface area and excellent conductivity of the MXene. The fabricated sensor demonstrated a simple yet effective approach for the rapid and quantitative detection of AP, with a linear detection range of 0.032-160 μM and a low detection limit of 10 nM. Moreover, the sensor was successfully applied to detect AP in different water samples, validating its potential as a reliable and efficient tool for AP monitoring.

Electrosynthesis of Silane-Modified Magnetic Nanoparticles for Efficient Lead Ion Removal

The removal of heavy metal ions, such as lead (Pb2+), from aqueous systems is critical due to their high toxicity and bioaccumulation in living organisms. This study presents a straightforward approach for the synthesis and surface modification of iron oxide nanoparticles (IONPs) for the magnetic removal of Pb2+ ions. IONPs were produced via electrosynthesis at varying voltages (10-40 V), with optimal magnetic properties achieved at 40 V resulting in highly crystalline and magnetic IONPs in the gamma-maghemite (γ-Fe2O3) phase. IONPs were characterized using various techniques including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). A novel electrochemical method was developed for the silanization of IONPs using tetraethoxysilane (TEOS), (3-mercaptopropyl)trimethoxysilane (MPTMS) and (3-aminopropyl)triethoxysilane (APTES). The resulting silane-modified IONPs were evaluated for the magnetic removal of Pb2+ ions, with TEOS-modified IONPs demonstrating superior performance. This material exhibited a high adsorption capacity of 519 mg/g at a Pb2+ ion concentration of 300 ppm, and high removal efficiency across a range of Pb2+ ion concentrations, attributed to its Fe2O3@SiO2 core-shell structure. This study highlights the potential of the electrochemical synthesis and silanization of nanoparticles for heavy metal remediation in water.

In Vitro and In Vivo Biological Activities of Dipicolinate Oxovanadium(IV) Complexes

The work is focused on anticancer properties of dipicolinate (dipic)-based vanadium(IV) complexes [VO(dipic)(N^∩N)] bearing different diimines (2-(1H-imidazol-2-yl)pyridine, 2-(2-pyridyl)benzimidazole, 1,10-phenanthroline-5,6-dione, 1,10-phenanthroline, and 2,2'-bipyridine), as well as differently 4,7-substituted 1,10-phenanthrolines. The antiproliferative effect of V(IV) systems was analyzed in different tumors (A2780, HCT116, and HCT116-DoxR) and normal (primary human dermal fibroblasts) cell lines, revealing a high cytotoxic effect of [VO(dipic)(N^∩N)] with 4,7-dimethoxy-phen (5), 4,7-diphenyl-phen (6), and 1,10-phenanthroline (8) against HCT116-DoxR cells. The cytotoxicity differences between these complexes can be correlated with their different internalization by HCT116-DoxR cells. Worthy of note, these three complexes were found to (i) induce cell death through apoptosis and autophagy pathways, namely, through ROS production; (ii) not to be cytostatic; (iii) to interact with the BSA protein; (iv) do not promote tumor cell migration or a pro-angiogenic capability; (v) show a slight in vivo anti-angiogenic capability, and (vi) do not show in vivo toxicity in a chicken embryo.

Ni(OH)2-Type Nanoparticles Derived from Ni Salen Polymers: Structural Design toward Functional Materials for Improved Electrocatalytic Performance

Herein, we report the potential-driven electrochemical transformation carried out in basic media of two Ni2+ salen polymers, (poly(NiSalen)s), abbreviated as poly(meso-NiSaldMe) and poly(NiSaltMe). These two polymers, with different configurations of methyl substituents on the imine bridge, were used as precursors for the preparation of electrocatalytically active nickel hydroxide [Ni(OH)2]-type nanoparticles (NPs) anchored in the polymeric matrix as poly[SalenNi(OH)2]. The use of potentiodynamic and potentiostatic electropolymerization conditions for the deposition of polymeric precursors allowed us to control the molecular architecture of poly(NiSalen)s and NPs derived from them. Thus, we obtained different arrangements of NPs embedded in morphologically different poly(Salen) matrixes, indicating their electrocatalytic activity toward ethanol to different extents. Moreover, we found a direct relationship between the electrochemical stability of the poly(NiSalen) precursors operating in the organic solvent-based electrolyte solutions and the easiness of their transformation into Ni(OH)2 NPs operating in the aqueous alkaline media. Poly(NiSalen)s and Ni(OH)2-type NPs were characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy.

Dicyandiamide-assisted HKUST-1 derived Cu/N-doped porous carbon nanoarchitecture for electrochemical detection of acetaminophen

MOFs-derived metal/carbon materials have been considered as promising candidates for the electrochemical detection of micropollutants. However, the aggregation of metal nanoparticles and structure collapse of precursor MOFs during pyrolysis significantly hamper the improvement on detecting performance. Herein, a dicyandiamide-assisted strategy is utilized to synthesize well-dispersed Cu/N-doped porous carbon nanoarchitecture (CuNC) for the electrochemical detection of acetaminophen (AP). The constructed CuNC sensor exhibits excellent electro-analytical performance for monitoring AP with linear range from 0.01 μM to 921.2 μM, and the low detection limit of 2.46 nM (S/N = 3). The improved performance of CuNC sensor is ascribed to the introduction of dicyandiamide, which can prevent HKUST-1 framework breakage and reduce the aggregation tendency of Cu, leading to the evenly distributed small Cu nanoparticles, abundant N species, hierarchical channel structure, and high conductivity carbon framework. These advantages endow predominant repeatability, stability, and selectivity of CuNC sensor. This strategy provided a novel approach to preparing MOFs-derived carbon nanoarchitectures with excellent electroanalysis performance to monitor micropollutants.