Transition Metal Chemistry最新文献

A novel Copper(II) complex based on mixed ligands, the phytochemical compound baicalein and ancillary ligand 1,10-phenanthroline, [Cu(baic)(phen)NO₃], was synthesized and characterized by UV–visible, FTIR, EPR, and mass spectrometry. The analysis of the geometry was further analyzed using DFT, yielding a narrow HOMO–LUMO gap (2.63 eV), reflecting enhanced reactivity. The complex was found to have copper in the +2-oxidation state and to be penta-coordinated. Studies of DNA and BSA interaction were carried out using UV and FL spectroscopic assays revealed satisfactory binding affinity to DNA, with statistical values of K_b = 1.26 × 10⁴ M⁻¹ and K_sv = 2.71 × 10³ M ¹, and to BSA, with K_sv = 1.15×10⁵ M⁻¹, respectively. EtBr quenching studies gave us insight into the partial intercalative mode of complexation, and to correlate the same, we performed molecular docking studies. It revealed that the experimentally observed DNA-binding affinity, with a binding constant of (1.26 ± 0.10) × 10⁴ M⁻¹, was complemented by molecular docking against the 2D55 DNA duplex, which produced a binding score of −6.9 kcal/mol and a mixed, partially intercalative binding orientation; redocking of the native ligand yielded an RMSD of 0.376 Å, supporting the reliability of the docking protocol. This agreement was extended over 100 ns MD simulations, which confirmed stable, low-RMSD/RMSF binding of the complex to both DNA (2D55) and riboflavin kinase (1QS9), a metastasis-associated enzyme, thereby providing a plausible molecular rationale for the anti-metastatic phenotype observed in the cell-based assays. The complex exhibited moderate selective cytotoxicity against A549 cells (IC₅₀ = 115 µg/ml [201 µM]) relative to L929 cells (IC₅₀ = 458.21 µg/ml [800 µM]), with a ~4-fold increase in apoptosis and dose-dependent caspase−3 activation. To understand the [Cu(baic)(phen)NO₃]’s anti-metastasis activity, wound healing assays were performed, and they demonstrated 38% suppression of cell motility at 48 h, whereas Transwell invasion assays confirmed >50% inhibition at the IC₅₀ concentration of the complex. The complex was found to be more effective as an anti-metastasis agent than as a cytotoxic agent.Taken together, the mutual reinforcement of spectroscopic, cellular, and computational evidence indicates that the complex behaves as a considerably more effective anti-metastatic than cytotoxic agent.

To overcome the low dye adsorption efficiency of pristine nickel oxide (NiO) arising from its limited specific surface area and underdeveloped pore structure, a hierarchically porous nano-NiO adsorbent was constructed via a combined hydrothermal and low-temperature calcination process, using a rosin-based gemini surfactant (DA-n-CYS) as the structural modulator. The structure and morphology of the synthesized material were systematically characterized using Fourier transform infrared (FT-IR), X-ray diffraction(XRD), scanning electron microscopy(SEM), and Brunauer-Emmett-Teller(BET). The adsorption kinetics and thermodynamic mechanisms for methyl orange (MO) and methylene blue (MB) were comprehensively investigated. The directional growth of NiO crystals was demonstrated to be effectively induced by DA-n-CYS, which resulted in a meso-macroporous hierarchical structure with a specific surface area ranging from 90 to 110 m²/g. Superior dye adsorption performance was exhibited by the obtained material, and the adsorption process was well-described by the pseudo-second-order kinetic model and the Langmuir isotherm model, yielding remarkably high theoretical maximum adsorption capacities of 202.1 mg/g and 146.8 mg/g for MB and MO, respectively. Furthermore, a preferential adsorption selectivity towards the cationic dye (MB) was demonstrated by the nano-NiO, and a high removal efficiency of over 93% was maintained even after ten regeneration cycles. Consequently, a crucial theoretical basis is provided by this study for the structural design and industrial application of NiO-based adsorbents in dye wastewater treatment.

A new metal-organic framework [Zn(4-cptpy)(HCOO)(H₂O)]·DMF (1)(Hcptpy = 4-[4,2’:6’,4’’-terpyridine]-4’-yl-benzoic acid), has been solvothermally synthesized, and its structure has been characterized by single crystal X-ray diffraction, infrared spectroscopy, elemental analysis, X-ray powder diffraction and thermogravimetric analysis. 1 is composed of Zn(II) ions, 4-cptpy⁻ ligands, formate and coordination water molecules. Each Zn(II) ion is in a twisted cis-N₂O₄ octahedral environment and is connected with three ligands, and each ligand coordinates with three Zn(II) ions to form a hexagonal honeycomb with a 2D layered (6,3)-connected net. Two 2D porous nets are interlaced with each other to produce a 2-fold interpenetrated net. In addition, the fluorescent properties of 1 in various metal nitrate@DMF solutions and nitroaromatic compounds (NACs)@DMF solutions were studied. The results show that: 1 exhibits a highly sensitive and selective response to Fe³⁺ and 2,4,6-trinitrophenol (TNP) through fluorescence quenching effect, and it is expected to become a fluorescence sensor for Fe³⁺ and TNP. Finally, the possible fluorescence quenching mechanisms of Fe³⁺ and TNP detection are discussed: (a) photoinduced electron transfer (PET) and (b) fluorescence resonance energy transfer (FRET) through the HOMO-LUMO energy gap of density functional.

Graphical Abstract

A new metal–organic framework based on 4-[4,2’:6’,4’’-terpyridine]-4’-yl-benzoic acid ligand was synthesized and structurally characterized in detail, and complex 1 is promising bifunctional fluorescent probe for highly sensitive and selective sensing Fe3+ ions and TNP through fluorescence quenching effect. The quenching mechanisms and recyclabilites of complex 1 were studied based on both experiments and calculation.

A density functional theory investigation was performed to elucidate the nature of metal–hydrogen interactions and hydrogen-storage behavior in Li- and Sc-functionalized [3]paracyclophane. Geometry optimizations show that Li and Sc preferentially bind above the benzene ring centers, with metal binding energies of − 0.683 and − 1.364 eV for the monometallic Li-PCP and Sc-PCP systems, respectively. For single H₂ adsorption, Li functionalization increases the adsorption energy to − 0.126 eV, with Li–H distances of 2.08–2.14 Å and only a slight H–H elongation from 0.74 to 0.75 Å, consistent with predominantly polarization-assisted electrostatic adsorption. Sc functionalization produces substantially stronger adsorption of − 0.344 eV, with Sc–H distances of 2.15–2.17 Å and an H–H bond length of 0.77 Å, indicating a stronger but still molecular interaction. Complementary EDA, PDOS, CDA/ECDA, and IGMH analyses show that Sc–H₂ binding involves significant electrostatic and polarization contributions together with donation-dominated orbital interaction and limited back-donation. Sequential adsorption calculations show that 2Li-PCP and 2Sc-PCP accommodate up to 8 and 10 H₂ molecules, respectively, within the loading range examined, corresponding to theoretical gravimetric capacities of 6.1 and 5.8 wt%. Thermodynamic analysis yields effective reversible capacities of 1.3 wt% for Li-PCP and 4.4 wt% for Sc-PCP, demonstrating the superior practical retention behavior of the Sc-functionalized system. Comparison with previously reported paracyclophane homologues confirms that the [3] framework provides an intermediate regime of metal stabilization and hydrogen binding. Overall, these results clarify how metal identity and bridge length govern molecular H₂ adsorption and reversible storage in functionalized paracyclophanes.

Two well-known strained ruthenium(II) complexes, [Ru(phen)(dmphen)₂](PF₆)₂ (1) and [Ru(phen)₂(dmphen)](PF₆)₂ (2), where phen = 1,10-phenanthroline, dmphen = 2,9-dimethyl-1,10-phenanthroline, were synthesized and their photo-induced anticancer activities were explored. Results showed that complex 1, which possessed a bulkier configuration, exhibited potent phototherapeutic activity against the non-small-cell lung carcinoma cell line (A549), with an IC₅₀ of 1.1 µM and a phototoxicity index (PI) of 18.6 under white light irradiation. Mechanistic studies revealed that 1 underwent ligand dissociation, promoted reactive oxygen species (ROS) generation, and effectively triggered DNA damage response and cell cycle arrest, ultimately inducing apoptosis in A549 cells.

Metal–organic frameworks (MOFs) were long valued for their crystalline regularity, and structural defects, including missing-linker vacancies, missing-node sites, substitutional disorder, surface terminations, and correlated vacancy domains, were initially dismissed as synthetic imperfections to be minimized. Over the past decade, this view has inverted: defects are now recognized as a reproducible, structurally significant feature of MOFs that can be deliberately introduced and controlled. This review discusses the fundamental principles of defect engineering, examining how modulated synthesis, kinetic control, and post-synthetic treatment are used to install specific defect populations, and how multi-technique characterization, including solid-state NMR, pair distribution function analysis (PDF), X-ray absorption spectroscopy (XAS), electron microscopy, and operando measurements, has made it possible to resolve defect type, density, and spatial distribution rather than merely confirm their presence. We then examine how this design-level control translates into the development of applied interfaces and functional materials across both established and emerging domains: defect engineering is now well established for engineering functional interfaces in catalysis and gas adsorption/separation, and is rapidly extending into less mature areas including electrochemical energy storage, environmental remediation, and biomedical delivery, where defect-function relationships remain less quantitatively resolved. We conclude by identifying the reproducibility, quantification, and scalability barriers that currently separate empirical defect discovery from predictive, data-driven of defect-engineered functional materials and applied interfaces.

The rapid expansion of high-tech and clean energy applications has dramatically escalated the global demand for scandium (Sc), necessitating its sustainable recovery from secondary industrial waste streams. In this study, the leaching behavior, parametric optimization, and dissolution kinetics of scandium from iron–aluminum precipitation residues derived from High-Pressure Acid Leaching (HPAL) were systematically investigated. Characterization of the feedstock confirmed an iron-dominated matrix (33.93 wt% Fe, 3.39 wt% Al) containing 44.70 ppm Sc substituted within host goethite, hematite, and natrojarosite mineral phases. Lixiviant evaluation revealed that ascorbic acid achieved superior scandium extraction efficiency compared to conventional organic acids by driving the complete reductive dissolution of the host ferric matrix, albeit with substantial co-dissolution of bulk impurities. Experimental optimization demonstrated that maximum scandium extraction was achieved at 90 °C, an ascorbic acid concentration of 3 mol/L, and a solid-to-liquid ratio of 100 g/L over a 60-minute duration. Kinetic modeling across six distinct mathematical formulations established that the Zhuravlev–Lesokhin–Tempelman (ZLT) model provides the most accurate physical description of the leaching process across 30–90 °C, yielding an apparent activation energy (E_a) of 64.59 kJ/mol. This confirms that scandium extraction is governed by a chemically activated interfacial reaction coupled with three-dimensional diffusion through the porous product layer. Overall, these findings present an environmentally benign hydrometallurgical route that effectively disrupts industrial HPAL neutralization sludges to unlock critical metals for subsequent downstream separation.

Transition-metal-based molecular switches offer a promising platform for nanoscale electronics owing to their reversible redox activity and tunable electronic structures. In this work, machine learning (ML) was employed to screen 1,248 coordination complexes and identify promising Ru(II)- and Os(II)-based molecular switches, followed by density functional theory (DFT), time-dependent density functional theory (TD-DFT), and nonequilibrium Green’s function (NEGF) calculations. The optimized complexes exhibited stable distorted octahedral coordination environments with minimal structural variation upon metal substitution. The calculated highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gaps were 3.11 and 3.18 eV for Ru(II) and Os(II), respectively, with effective metal–ligand charge transfer and electronic delocalization. Redox calculations predicted reversible Ru(II)/Ru(III) and Os(II)/Os(III) one-electron oxidation with potentials of 0.78 and 1.12 V versus the standard hydrogen electrode (SHE), respectively, consistent with previously reported experimental values for structurally related systems. NEGF calculations revealed higher zero-bias conductance for the Ru(II) switch (28.7 μS) and a superior ON/OFF ratio of 63.2 compared with the Os(II) analogue. The combined ML and quantum-chemical analyses identify metal identity, ligand donor characteristics, orbital delocalization, electronic coupling, reorganization energy, and redox reversibility as key factors governing molecular switching performance for future molecular-scale electronic device design.

The development of efficient, stable, and cost-effective bifunctional electrocatalysts for overall water splitting is crucial for green hydrogen production. Herein, we report a series of indium-doped nickel-cobalt layered double hydroxide (In-NiCo LDH) catalysts synthesized directly on nickel foam via a one-step electrodeposition method. By varying the In doping concentration, we identified the optimal In/(Ni + Co) molar ratio of 1.0% that delivers exceptional bifunctional activity. The optimized In_1.0-NiCo LDH electrode exhibits low overpotentials of 215 mV for the oxygen evolution reaction (OER) and 180 mV for the hydrogen evolution reaction (HER) at 100 mA cm^− 2, with small Tafel slopes of 71.53 mV dec^− 1 (OER) and 47.69 mV dec^− 1 (HER). Structural characterization reveals that In³⁺ ions are incorporated as interstitial defects into the LDH lattice, causing distorted electronic structure. This unique doping mode creates new active sites that serve as electron-donating sites for HER and electron-withdrawing sites for OER. Furthermore, the In_1.0-NiCo LDH demonstrates remarkable long-term stability, maintaining stable operation for 100 h in both OER and HER tests. When assembled as a two-electrode electrolyzer, it requires only 1.73 V to achieve 100 mA cm^− 2 for overall water splitting. This work presents a facile electrodeposition strategy for fabricating high-performance In-doped NiCo-LDH bifunctional catalysts and elucidates the structure-activity relationship governed by atomic doping engineering.

The weak intrinsic second-harmonic generation (SHG) of most nanomaterials severely restricts their practical applications. Interfacial engineering offers a promising route to boost nonlinear optical responses. Herein, a heterointerface is fabricated between ZrCl₄-BDC metal-organic frameworks (ZrCl₄-BDC MOFs) and carbon dots (CDs), and this heterointerface produces a prominent enhancement of second-harmonic generation (SHG). The SHG intensity of the ZrCl₄-BDC MOFs-CDs nanocomposite at 720 nm (excitation at 360 nm) reaches 9162 a.u., which is markedly higher than the sum of the individual contributions from the ZrCl₄-BDC MOFs (6150 a.u.), CDs (210 a.u.), and water (60 a.u.), demonstrating a clear synergistic effect that exceeds the sum of its parts. The enhanced SHG originates from the formation of a heterointerface between ZrCl₄-BDC MOFs and the CDs, which is primarily attributed to charge-transfer interactions at the heterointerface, together with improved particle dispersion and local field enhancement. This ZrCl₄-BDC MOFs-CDs-water system not only provides a sensitive platform for studying interfacial charge transfer and nonlinear optical enhancement at the nanoscale but also holds great promise for high-contrast label-free bioimaging, ultrasensitive chemical/biological sensing, and tunable nanophotonic devices, owing to its excellent water dispersibility and dual-modal (fluorescence/SHG) optical response.