Search Results (190)

A new series of promising and easily accessible antiproliferative agents based on cycloruthenated imines of benzene and thiophene carbaldehydes has been developed and fully characterized using UV-Vis spectroscopy, X-ray diffraction, NMR, HRMS, and cyclic voltammetry. The biological activity of these compounds was tested against A2780, cisplatin-resistant A2780, and HEK293 cell lines, and they exhibited nanomolar IC₅₀ values. They also showed a selectivity index of up to 2.5, indicating their potential as promising antiproliferative compounds. Full article

The accurate determination of trace metals in aqueous matrices necessitates robust sample preparation techniques that enable selective preconcentration of analytes while ensuring compatibility with subsequent instrumental analysis. Dispersive solid-phase extraction (d-SPE), a suspension-based variant of conventional solid-phase extraction (SPE), facilitates rapid sorbent–analyte interactions and enhances mass transfer efficiency through direct dispersion of the sorbent in the sample solution. This approach offers significant advantages over traditional column-based SPE, including faster extraction kinetics and greater operational simplicity. When supported by appropriately engineered sorbents, d-SPE exhibits considerable potential for the selective enrichment of trace metal analytes from complex aqueous matrices. In this work, a fibrous silica-based chelating material, DSA-KCC-1, was synthesized by grafting 3,5-Di-tert-butylsalicylaldehyde (DSA) onto aminopropyl-modified KCC-1. The dendritic KCC-1 scaffold enables fast dispersion and short diffusion pathways, while the immobilized phenolate–imine ligand introduces defined binding sites for transition-metal uptake. Characterization by FTIR, TGA, BET, FESEM/TEM, XRD, and elemental analysis confirmed the successfulness of functionalization and preservation of the fibrous mesostructured. Adsorption studies demonstrated chemisorption-driven interactions for Pb(II) and Co(II) from water, with Langmuir-type monolayer uptake and pseudo-second-order kinetic behavior. The nano-adsorbent exhibited a markedly higher affinity for Pb(II) than for Co(II), with maximum adsorption capacities of 99.73 and 66.26 mg g⁻¹, respectively. Integration of the DSA-KCC-1 nanosorbent into a d-SPE–ICP-OES workflow enabled the reliable determination of trace levels of the target ions, delivering low limits of detection, wide linear calibration ranges, and stable performance over repeated extraction cycles. Analysis of NIST CRM 1643d yielded results in good agreement with the certified values, while the method demonstrated high tolerance toward common coexisting ions. The combined structural features of the KCC-1 support and the Schiff-base ligand indicate the suitability of DSA-KCC-1 for d-SPE workflows and demonstrate the potential of this SPE format for selective preconcentration of trace metal ions in aqueous matrices. Full article

Herein, we prepared nanoparticles of chitosan–manganese(II) complexes in different molar ratios (1:2, 1:1, and 2:1) and fully characterized them using dynamic and electrophoretic light scattering, X-ray diffraction, SEM, FTIR, and thermal analysis. Nanoparticles Chitosan + Mn²⁺ (1:1) have a high catalytic activity in the oxidative coupling of benzylamine, resulting in the imine formation and also in selective aldol reaction. Chitosan + Mn²⁺ (1:1) catalyze the reactions in the greenest solvents: water and water/ethanol mixture. Moreover, Chitosan + Mn²⁺ (1:1) is very easy to prepare and convenient to use. The catalyst is separated from the reaction mixture by a simple nanoporous filter or centrifugation and does not lose catalytic activity after at least ten uses. The chitosan–manganese(II) complexes reduce the milk fermentation time, demonstrating the effectiveness in accelerating the fermentation process by Streptococcus thermophilus. They also contribute to increasing the shelf life of fermented milk products by inhibiting the undesirable post-acidification process. We found that the optimal ratio of chitosan and Mn²⁺ to manifest the apogee of the desired effects (acceleration of milk fermentation and increase in the shelf life of the fermented product) is 1:2. Full article

Benzoxazoles are recognized as significant building blocks in organic synthesis and materials science. This work observed the formation of benzoxazole from o-aminophenol and o-hydroxybenzaldehyde using online ¹H NMR (continuous flow cell, 80 MHz). The identification of changes in the functional group was complemented by ATR-FTIR analysis. Additionally, the kinetic roles of phenylboronic acid and cyanide in the one-pot condensation-cyclization reaction are examined. Real-time monitoring has revealed three observable events: the rapid condensation of the aldehyde and o-aminophenol to produce the imine; the formation of the boron complex in the presence of phenylboronic acid; and the cyanide-assisted cyclization that converts the intermediate into benzoxazole. The findings clarify the transformations that control throughput and provide valuable insights for optimizing reagent loadings under environmentally friendly conditions. Full article

Alzheimer’s disease (AD) is a complex neurodegenerative disease. The pathogenesis of AD remains incompletely understood. It is characterized by a variety of neuropathological changes, including neuroinflammation, neuronal loss and synaptic damage. Multiple pathological changes make achieving good therapeutic effects with a single drug treatment difficult, and using multiple drugs for combination therapy is currently the most effective method. Currently, the mainstay drugs used for AD treatment are hydrophobic drugs, such as curcumin, donepezil, and resveratrol. Because hydrophobic drugs cannot dissolve in bodily fluids and often aggregate or precipitate, their efficacy is greatly reduced. Therefore, there is an urgent need for a drug carrier that can effectively load and continuously release drugs. However, currently, there are few drug carriers that can achieve efficient co-loading of multiple hydrophobic drugs. Therefore, three of two-dimensional imine covalent organic frameworks (COFs) with different monomers were synthesized through rational design and screening. These three synthesized COFs are simultaneously loaded with curcumin (CUR) and benzofurazan (BZ) to achieve combined therapy. The results indicate that among this series of synthesized COFs, the COF synthesized from 4,4′,4″-(1,3,5-Triazine-2,4,6-triyl) trianiline and benzene-1,3,5-tricarboxaldehyde (COF-TB) exhibits optimal hydrophobic drug-loading capacity, enabling effective co-loading of CUR and BZ (BC@COF-TB). After treatment with BC@COF-TB, the cognitive function of 5×FAD mice was significantly improved. The COF platform provides a new way to deliver hydrophobic drugs for AD treatment. Full article

Upon the reaction of glyoxal-bis(2-hydroxy-5-chlorophenyl)imine LH₂ with diethyltin dichloride in the presence of a base (Et₃N) in DMSO, the 1D-coordination polymer 1 was obtained, in which formally the L’(SnEt₂)₂ fragment acts as a monomeric unit. It was found that during the reaction, the initial ligand L undergoes transformation in the tin atom’s coordination sphere. This transformation results in the formation of a new ditopic 1,4-bis((5-chloro-2-oxidophenyl)imino)but-2-ene-2,3-bis(olate) ligand L’. The structure of the resulting complex 1 was examined by single-crystal X-ray diffraction analysis, elemental analysis, IR, and UV spectroscopy. Full article

In this work, a new asymmetric amidine–imine ligand, using 1,8-diaminonaphthalene as a rigid platform, was synthesized and characterized, and its ability to form complexes with aluminum(III) was investigated. Several aluminum complexes were synthesized and characterized in solution and in the solid state. The synthesis of a dihalogenated aluminum(III) complex (AlI₂L) using a reducing agent revealed an atypical pathway, which was investigated using Density Functional Theory (DFT). The dimethylated aluminum complex AlMe₂L and the dihalogenated aluminum complex AlI₂L were evaluated as catalysts for the transformation of CO₂ and epoxides into cyclic carbonates in the presence of Bu₄NI as a co-catalyst or in a single-component system, respectively. AlMe₂L/Bu₄NI appeared to be the most efficient system under 1 bar of CO₂ at 90 °C. Full article

The present study reports the sono-chemical synthesis of novel nanosized Cr(III), Mn(II), and Pd(II) complexes incorporating the chloro-2-(quinolin-8-yliminomethyl)-phenol imine ligand. The synthesized complexes were characterized using various spectroscopic and analytical techniques, including Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The results confirmed the successful coordination of the ligand-to-metal centers, forming stable nanosized metal complexes with distinct physicochemical properties. Biological evaluations, including antimicrobial and antioxidant assays, revealed that the synthesized complexes exhibited enhanced biological activity compared to the free ligand, demonstrating potent antibacterial and antifungal properties against various pathogenic strains. The potential of the complexes to serve as efficient free-radical inhibitors was determined by employing DPPH radical scavenging assays, which underscored their significant antioxidant properties. Furthermore, molecular docking studies were conducted to elucidate the binding interactions of the metal complexes with biological targets, providing insights into their mechanism of action. The findings suggest that the synthesized nanosized Cr(III), Mn(II), and Pd(II) complexes possess promising biological properties, making them potential candidates for pharmaceutical and biomedical applications. The study also demonstrates the effectiveness of sono-chemical synthesis in producing nanosized metal complexes with enhanced physicochemical and biological characteristics. Full article

Background/Objectives: To design the pDNA delivery carrier for delivery into skeletal muscle, a total of twelve terminal-alkylated PEGs (Cx-I-PEGy) with four alkyl groups of different carbon numbers (Cx: x = 4, 8, 12, 16) modified via an imine spacer at the ends of three methoxy PEGs of different molecular weights (PEGy: y = 500, 2k, 5k) have been synthesized. Methods: Among them, four Cx-I-PEG5k formed an imine-mediated complex formation with pDNA, as assessed by agarose gel electrophoresis, defined as an iminium mono-ion complex (I-MIC) without multivalent electrostatic interaction by minimizing potential toxic cations. Results: Most resulting I-MICs maintained the flexible structure of pDNA and promoted the binding to pDNA. The expression of pDNA by intramuscular injection with the resulting I-MICs was the highest by using I-MICs with C4-I-PEG5k and was observed extensively by the in vivo imaging system (IVIS). Conclusions: These results suggest that the I-MICs with C4-I-PEG5k are promising for pDNA transfection into skeletal muscle, offering the alkyl iminium for the pDNA binding group to demonstrate the factor of pDNA’s flexible structure as one of the key parameters for in vivo local pDNA transfection. Full article

Alzheimer’s disease (AD) is a multi-factorial neurodegenerative disease with a complex pathomechanism that can be best treated with multi-target medications. Among the possible molecular targets involved in AD, acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B) are well recognized because they control the neurotransmitters responsible for memory processes. This review discusses the current understanding of AD pathology, recent advances in AD treatment, and recent reports in the field of dual AChE/MAO-B inhibitors for treating AD. We provide a classification of dual inhibitors based on their chemical structure and describe active compounds belonging to, i.a., chalcones, coumarins, chromones, imines, and hydrazones. Special emphasis is given to the computer-aided strategies of dual inhibitors design, their structure–activity relationships, and their interactions with the molecular targets at the molecular level. Full article

Cyclic voltammetry (CV) is an accessible, readily available, non-expensive technique that can be used to search for the interaction of compounds with DNA and detect the strongest DNA-binding from a set of compounds, therefore allowing for the optimization of the number of cytotoxicity assays. Focusing on this electrochemical approach, the study of twenty-seven camphorimine silver complexes of six different families was performed aiming at detecting interactions with calf thymus DNA (CT-DNA). All of the complexes display at least two cathodic waves attributed respectively to the Ag(I)→Ag(0) (higher potential) and ligand based (lower potential) reductions. In the presence of CT-DNA, a negative shift in the potential of the Ag(I)→Ag(0) reduction was observed in all cases. Additional changes in the potential of the waves, attributed to the ligand-based reduction, were also observed. The formation of a light grey product adherent to the Pt electrode in the case of {Ag(OH)} and {Ag₂(µ-O)} complexes further corroborates the interaction of the complexes with CT-DNA detected by CV. The morphologic analysis of the light grey material was made by scanning electronic microscopy (SEM). The magnitude of the shift in the potential of the Ag(I)→Ag(0) reduction in the presence of CT-DNA differs among the families of the complexes. The complexes based on {Ag(NO₃)} exhibit higher potential shifts than those based on {Ag(OH)}, while the characteristics of the ligand (^AL-Y, ^BL-Y, ^CL-Z) and the imine substituents (Y,Z) fine-tune the potential shifts. The energy values calculated by docking corroborate the tendency in the magnitude of the interaction between the complexes and CT-DNA established by the reaction coefficient ratios (Q_[Ag-DNA]/Q_[Ag]). The molecular docking study extended the information regarding the type of interaction beyond the usual intercalation, groove binding, or electrostatic modes that are typically reported, allowing a finer understanding of the non-covalent interactions involved. The rationalization of the CV and cytotoxicity data for the Ag(I) camphorimine complexes support a direct relationship between the shifts in the potential and the cytotoxic activities of the complexes, aiding the decision on whether the cytotoxicity of a complex from a family is worthy of evaluation. Full article

A series of para-trifluoromethoxy-substituted and fluorobenzhydryl-functionalized 1,2-bis(imine)acenaphthene ligands: 1-[2,6-{(4-F-C₆H₄)₂CH}₂-4-F₃COC₆H₂N]-2-(ArN)C₂C₁₀H₆ (Ar = 2,6-Me₂C₆H₃ L1, 2,6-Et₂C₆H₃ L2, 2,6-iPr₂C₆H₃ L3, 2,4,6-Me₃C₆H₂ L4, 2,6-Et₂-4-MeC₆H₂ L5), were synthesized and used to generate their corresponding nickel(II) bromide complexes (Ni1–Ni5). Elemental analysis, ¹⁹F NMR, and FT-IR spectroscopy were employed to characterize these five nickel complexes. Single-crystal X-ray diffraction of Ni2 and Ni4 confirmed distorted tetrahedral geometries. Upon activation with either EtAlCl₂ (ethylaluminum dichloride) or EASC (ethyl aluminum sesquichloride), these complexes showed exceptional high activities (up to 22.0 × 10⁶ g PE mol⁻¹ (Ni) h⁻¹) and remarkable thermal stability (4.82 × 10⁶ g PE mol⁻¹(Ni) h⁻¹ at 80 °C) towards ethylene polymerization. The resulting polyethylenes are highly branched, with the type and extent of branches tunable by temperature, solvent, and co-catalyst choice. Moreover, these polymers demonstrated excellent tensile strength (σ_b up to 20.7 MPa) and elastic recovery (up to 58%), characteristic of thermoplastic elastomers (TPEs). These results highlight the dual role of trifluoromethoxy and fluorobenzhydryl groups in enhancing catalytic performance and polymer properties. Full article

Noble metals are widely recognized for their ability to catalyze the electro-oxidation of organic compounds, with smaller particle sizes significantly enhancing electrocatalytic activity. In this study, catalytic electrodes decorated with atomic-level platinum and Pt-Au clusters were fabricated using cyclic atomic-metal electrodeposition. The interactions between the iminium (protonated imine) groups in emeraldine salt polyaniline (PANI) and metal chloride complexes in the electrolyte enabled precise control over the cluster size and composition. The electrocatalytic activity of these electrodes for propanol oxidation was systematically evaluated using cyclic voltammetry (CV). Notably, PANI electrodes decorated with odd-numbered atomic-level Pt clusters exhibited higher peak oxidation currents compared to even-numbered clusters, revealing a unique even–odd effect. For atomic-level Pt-Au clusters, the catalytic activity was significantly influenced by the sequence of Pt and Au deposition, with PANI-Au₁Pt₃ achieving the highest catalytic activity (35.34 mA/cm²). Bi-metallic clusters consistently outperformed mono-metallic clusters, and clusters containing only one Pt atom demonstrated superior catalytic activity. These findings provide valuable insights into the design of high-performance catalytic electrodes by leveraging atomic-level control of the cluster size, composition, and deposition sequence, paving the way for advanced applications in electrochemical sensors. Full article

Several CNN pincer Pd(II) complexes including chiral complexes 1a–e with 2-phenyl-6-(oxazolinyl)pyridines and achiral ones 2a–c with N-substituted-2-aminomethyl-6-phenylpyridines were prepared. In addition, the preparation of the achiral PCN pincer Pd(II) complexes 3a–e with aryl-based phosphinite–imine ligands and chiral 4a–c with aryl-based phosphinite–imidazoline ligands was also performed. Among them, the PCN Pd(II) pincers 3a–e were new complexes and were readily synthesized from commercially available materials in only two steps. The new complexes were characterized through elemental analyses, namely ¹H NMR, ¹³C{¹H} NMR, and ³¹P{¹H} NMR spectroscopies. Furthermore, the molecular structure of complex 3a was determined via X-ray single-crystal diffraction analysis. In the presence of EtAlCl₂, Et₂AlCl, or methylaluminoxane (MAO), the CNN pincer Pd(II) complexes and PCN pincer Pd(II) complexes exhibited excellent activities and monomer conversion rates in norbornene addition polymerization. Surprisingly, the CNN pincer Pd(II) complexes exhibited a higher conversion rate (99.5%) with Et₂AlCl as the cocatalyst, while the PCN pincer Pd(II) complexes showed a higher conversion rate (98.8%) with MAO. Full article

Despite the great successes achieved by metallocene catalysts in high-value-added polyolefin elastomer, the challenging preparation conditions and undesirable high-temperature molecular weight capabilities have compromised the efficiency and cost of polyolefin in industrial production. Recently, non-metallocene catalysts have received considerable attention due to their high thermostability, especially when coordinated with early transition metals. This review provides an overview of these early transition metal non-metallocene catalysts, which are mainly composed of N,N′-, N,O-, and N,S-bidentate complexes and tridentate complexes. The structural characteristics, catalytic performance, advantages, and disadvantages of the relevant non-metallocene catalysts, as well as their applications, are discussed. Candidates for commercialization of non-metallocene catalysts are proposed—focusing on imine-enamine, amino-quinoline, and pyridine-imine catalysts—by comparing the successful industrialization cases of metallocene catalysts. Finally, the trend in the research on non-metallocene catalysts and the strategies to address the challenges limiting their commercialization are considered. Full article