Dalton Transactions最新文献

The development of efficient and durable non-noble metal electrocatalysts toward the oxygen evolution reaction (OER) is critical for the high-efficiency storage of renewable energy. Herein, a facile and controllable sacrificial template strategy is reported. Using MIL-100(Fe) as the sacrificial template under alkaline conditions, a series of NiFe-LDH electrocatalysts are fabricated by regulating the feeding amount of the nickel source, to explore the influence of Ni/Fe molar ratio on the OER electrocatalytic performance. Systematic characterization studies and electrochemical tests reveal that the optimized NiFe-LDH delivers an overpotential of 242.2 mV at 10 mA cm^-2 together with a Tafel slope of 36.67 mV dec^-1, surpassing commercial IrO₂ and exhibiting remarkable long-term stability. Such outstanding electrocatalytic performance originates from the synergistic electronic interaction between Ni and Fe sites, which optimizes the adsorption energy of reaction intermediates and accelerates the reaction kinetics. This work not only offers a high-performance OER electrocatalyst, but also provides a versatile sacrificial template strategy for constructing advanced multimetallic electrocatalysts.

The synthesis and characterization of six new phosphonate linkers and their coordination networks are reported in this paper. All have the s-triazine heterocyclic core as a common structural feature and display mono- or di-substitution by aminoalkyl-phosphonate grafts. The phosphonate-bearing, amine-containing nucleophiles used for the substitution were amino-bis(methylenephosphonate) (ABMP), (3-amino-1-hydroxypropane-1,1-diyl)bis(phosphonic acid) (pamidronate, PAM), (4-amino-1-hydroxy-1-phosphonobutyl)phosphonic acid (alendronate, ALE), and (6-amino-1-hydroxyhexane-1,1-diyl)bis(phosphonic acid) (neridronate, NER). ABMP features a secondary amine, and PAM, ALE, and NER feature primary amines. The products isolated were Tr-1ABMP, Tr-1PAM, Tr-2PAM, Tr-1ALE, Tr-2ALE, and Tr-2NER (Tr = triazine; the numbers 1 and 2 indicate mono- and di-substitution). These ligands were used to synthesise coordination networks with alkaline earth metal ions. The crystal structures of three derivatives, namely Sr-Tr-1ABMP (2D), Ca-Tr-1PAM (1D), and Sr-Tr-2NER (1D), reveal the rich coordination chemistry and potential of these ligands. Tr-1PAM and Tr-2NER use only their phosphonate moieties for coordination, whereas Tr-1ABMP employs also the N and O atoms from the triazine ring. None of the structures display π-π stacking interactions. The structures of the metal derivatives are analysed and compared to several triazine-containing literature examples to determine the electronic and protonation state of the triazine ring. The triazine ring and external N atoms in the compounds Ca-Tr-1PAM, Sr-Tr-1ABMP, and Sr-Tr-2NER are planar, in agreement with the extended planarity concept. The protonation state of the triazine ring depends on the synthesis pH. The triazine ring is neutral (non-protonated) in Sr-Tr-1ABMP, but one of the N atoms is protonated in Ca-Tr-1PAM and Sr-Tr-2NER. This research establishes a promising entry to the coordination chemistry of phosphonate-substituted triazine rings. Such ligands can enrich the phosphorus synthetic chemist's "toolbox" for the creation of new coordination networks with diverse structure types.

Understanding how the uranyl ion (UO₂²⁺) exploits native metal-binding sites in human proteins is essential for elucidating uranium transport, accumulation, and toxicity. In this computational study, we investigated how uranyl is accommodated within the protein pockets of human serum transferrin and human serum albumin, and compared these interactions with those in an engineered super uranyl-binding protein (SUP). QM/MM geometry optimizations and harmonic vibrational frequency calculations were performed starting from available X-ray crystal structures. The intrinsic strengths of individual uranyl-protein interactions were quantified using Local Vibrational Mode Analysis (LMA), complementary with Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analyses. Histidine residues form the strongest individual U-N interactions, whereas aspartate and glutamate provided equally strong or stronger capture through bidentate U-O coordination. In human serum transferrin, the native carbonate cofactor forms an important component of the uranyl coordination sphere, whereas hydrogen bonds involving the uranyl oxo atoms contributed only weakly to binding. Comparison with the high-affinity SUP revealed that human serum proteins bind uranyl nearly as strongly as the engineered protein, highlighting their potential role in uranium transport and fate following human exposure.

The development of vectorized molecular photothermal agents is often limited by the lack of modular synthetic strategies that allow the introduction of biological vectors without compromising the properties of the previously engineered agents. Herein, we report a late-stage vectorization synthetic strategy where pyridinium quaternization of a preformed Fe(II)-terpyridine complex provides a straightforward and versatile access to libraries of vectorized agents while preserving their intrinsic photophysical and photothermal properties. This Fe(II)-terpyridine complex was used as a common synthetic intermediate for the final step introduction of biotin vectors bearing different linkers to afford the desired bis-vectorized complexes. Importantly, the quaternization strategy was designed to enhance the electron-withdrawing character of the ligand, hence reducing the energy of the metal-to-ligand charge-transfer transition for red shifting it toward the near-infrared region, thereby making them relevant for irradiation in photobiology. Beyond enhancing these previously engineered optical properties, late-stage vectorization substantially improved the in vitro biological behavior of the complexes. The vectorized complexes displayed enhanced cellular accumulation, confirmed by photoacoustic imaging, together with negligible in vitro dark toxicity, efficient photothermal conversion and cytotoxicity under irradiation, while maintaining high chemical and photostability. Overall, this work establishes late-stage functionalization by quaternization of a pre-formed Fe(II)-terpyridine complex as a modular design strategy to decorrelate functionalization with a vector as the final synthetic step from engineering the photothermal core, for producing performant vectorized Fe(II)-based agents active in photoacoustic imaging and photothermal therapy.

Integrated compositional and morphological designs provide an effective strategy to optimize both thermodynamic and kinetic behaviors, thus enabling the construction of high-efficiency electrocatalysts. Herein, we develop ReS₂ and FeS₂ heterojunction nanosheet arrays arranged on a carbon cloth substrate (labeled as ReS₂/FeS₂@CC hereafter) through a one-step hydrothermal strategy. Experimental data demonstrated that the construction of heterojunctions and sheet-like arrays can freely reconfigure the electronic configuration, expedite charge transfer, and provide abundant reactive sites. Consequently, the ReS₂/FeS₂@CC electrode exhibits outstanding hydrogen evolution performance in an alkaline medium, with an overpotential of 109 mV, affording a current density of 10 mA cm^-2, a Tafel slope of 103.7 mV dec^-1 and long-term electrochemical stability in the i-t test for 56 h and the 4000-cycle test, thereby offering a promising method for sustainable and economical H₂ production.

Boron-substituted silyllithium was synthesized via Sn-Li exchange between the corresponding (boryl)silylstannane and n-BuLi and reacted with chlorosilanes to afford a series of Si-B-containing di-, tri-, and tetrasilanes. The tri- and tetrasilane derivatives were examined by UV-vis spectroscopy and density functional theory calculations to assess the electronic consequences of boron incorporation into σ-conjugated silane frameworks. In addition, the diaminoboryl moiety bound to boron can be selectively transformed into a pinacolatoboryl group without Si-B bond cleavage. Overall, this work provides a chemically intuitive entry to Si-B-containing oligosilanes and enables systematic investigation of boron incorporation into σ-conjugated silane frameworks.

Intermetallic palladium-based nanomaterials hold great promise for alcohol electrooxidation, but the role of surface topography in governing interfacial catalytic processes remains underexplored. Herein, we report a comparative investigation of intermetallic Pd₃Pb nanosheets with flat and crumpled surface topographies, where the crumpled morphology is achieved by introducing N-(octadec-9-en-1-yl)diethanolamine during synthesis, while flat nanosheets are obtained in its absence. For ethanol oxidation, the crumpled Pd₃Pb nanosheets deliver a mass activity of 1742.9 mA mg^-1 and retain 10.0 mA cm^-2 after 100 cycles, substantially outperforming flat nanosheets (1192.8 mA mg^-1, 3.4 mA cm^-2) and commercial Pd/C (709.2 mA mg^-1, 1.1 mA cm^-2). In situ Raman spectroscopy reveals that the reaction proceeds predominantly via the C1 pathway, evidencing efficient C-C bond cleavage on the crumpled surface. By using density functional theory simulations this enhancement can be attributed to localized surface strain induced by the crumpled topography-modeled on the Pd₃Pb(311) surface-which upshifts the d-band center to -1.53 eV and strengthens *OH binding (-3.29 eV), thereby optimizing intermediate adsorption energetics and facilitating the oxidative removal of carbonaceous poisons. This work provides a synthetic route to engineer crumpled surface topography in intermetallic nanosheets and demonstrates its critical role in regulating interfacial catalysis for C1-selective alcohol electrooxidation.

Zero-dimensional organic-inorganic hybrid metal halides have emerged as promising luminescent materials with structural diversity and tunable emission properties. However, it remains challenging to precisely control the metal coordination environment to suppress non-radiative recombination and improve the photoluminescence quantum yield (PLQY). Herein, we report an acid-solvent synergistic strategy that enables stepwise evolution of Sb coordination environments in hybrid halides. The non-emissive phase (H₂PIP)[SbCl₅]·H₂O (1, PIP = piperazine), composed of edge-sharing [Sb₂Cl₁₀]^4- dimers, transforms into an orange-emitting intermediate (H₂PIP)₅(H₅O₂)[SbCl₅]₂[SbCl₆]Cl₄ (2) with mixed discrete polyhedra, in the presence of HCl. Upon CH₃CN incorporation, the mixed Sb coordination polyhedra transform into isolated [SbCl₆]^3- octahedra in green-emitting compound (H₂PIP)₂(NH₄)[SbCl₆]Cl₂·CH₃CN (3). Accompanying this evolution of coordination environments, the PLQY rises from <1% to 23.6% for the intermediate and ultimately reaches 90.4%. The enhanced PLQY originates from the expanded Sb⋯Sb distance and significant [SbCl₆]^3- octahedral distortion, which facilitate the formation and radiative recombination of self-trapped excitons. This work provides insights into acid-solvent directed coordination engineering for highly efficient Sb-based hybrid emitters.

A new heteroleptic luminescent and photocytotoxic ruthenium(II) polypyridyl complex, [Ru^II(bphen)₂(cur)]⁺ (bphen = bathophenanthroline, cur = curcumin), has been thoroughly investigated for its photophysical properties with potential as a luminescent probe for bioimaging and a photocytotoxic agent. The optimized lead complex was obtained via coordinating curcumin to the Ru(II) center pre-coordinated with two bathophenanthroline ligands, producing a stable cationic structure with extended π-conjugation. The incorporation of curcumin to {Ru(bphen)₂} moiety improves emissive characteristics and also enhances the biological compatibility, owing to its natural origin and functional groups that interact with biomolecular environments. The complex exhibits good photostability and strong emission under physiological conditions, enabling its application as a luminescent stain for fluorescence-based cellular imaging. Furthermore, in vitro photocytotoxicity studies in the human breast cancer cell line MCF-7 reveal a significant photocytotoxicity index (PI ∼ 19.5), indicating low dark toxicity but an enhanced cytotoxic response upon visible-light irradiation. These findings highlight the dual functionality of the [Ru^II(bphen)₂(cur)]⁺ as a theragnostic agent, serving as a luminescent bioimaging probe and a potential photosensitizing agent for light-activated therapeutic applications.