Types Of Ligands Research Articles

Ruthenium/η5-Phenoxo-Catalyzed Amination of Phenols with Amines.

Ruthenium(II) complexes are known to form η6-arene complexes with benzene-containing compounds through π-coordination, a property extensively utilized to initiate reactions not typically observed with free arenes. A prime example is nucleophilic aromatic substitution, where ruthenium-complexed aryl halides undergo nucleophilic attack, allowing the direct synthesis of diverse aromatic compounds by displacing halides with nucleophiles. However, this activation relies on the electron-withdrawing effect of the Ru(II) species, as well as is hindered by the resistance of η6-arenes to arene exchange. In the previous pursuit of catalysis, the emphasis of ligand design has centered on promoting arene exchange. In this study, we extended the ruthenium activation strategy to umpolung substitution reactions of phenols. The amination proceeds through a direct condensation between phenols and amines, with a key intermediate identified as [bis(η5-phenoxo)Ru], which is in situ generated from a commercially available ruthenium catalyst. In comparison with the well-studied cyclopentadienyl (Cp) type ligands, we demonstrated that an η5-phenoxo motif, as a superior alternative to Cp, contributes to the amination of phenols in two crucial ways: its less electron-donating nature enhances the withdrawing effect of the ruthenium unit, facilitating substitution on the phenol complex; its distinctive behavior in arene exchange allows for conducting the amination with a catalytic amount of metal. Additionally, hydrogen bonding, wherein the phenoxo serves as the acceptor, was found to be important for the substitution. The versatility of this ruthenium-catalyzed amination was validated by performing reactions with a diverse array of phenols exhibiting various electronic properties, in combination with a wide range of primary amines. This work exemplifies the expansion of the scope of π-coordination activation in catalysis through innovative ligand development.

The Theoretical Calculation of the Cu Isotope Fractionation Effect in Solution/Hydrothermal Solution Systems.

Copper (Cu) is an important transition metal, and its isotopes have important applications in geology, environmental science, soil science, and other fields. Cu isotope fractionation can occur in many natural processes. However, the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems is not very clear. In this study, the fractionation effects of complexes of Cu(I) and Cu(II) in solution/hydrothermal solution systems were systematically studied by means of an ab initio method based on first principles. In the simulation of an aqueous solution system, the theoretical treatment method used is the "water-droplet" method. The results show that the heavy Cu isotope (65Cu) enrichment capacity of the Cu-bearing complex solutions is greatly affected by the ligand types both for Cu(I) and Cu(II). For Cu(I) complex solutions, the heavy Cu isotope enrichment sequence is [Cu(HS)2]-·(H2O)42 > [Cu(HS)(H2O)]·(H2O)42 ≈ [Cu(HS)(H2S)]·(H2O)42 > [CuCl]·(H2O)42 > [CuCl2]-·(H2O)42 > [CuCl3]2-·(H2O)42. For the aqueous solutions of Cu(II) with an inorganic ligand (such as H2O, OH-, NO3-, SO42- and CN-), the order of heavy Cu isotope enrichment is as follows: [Cu(H2O)6]2+·(H2O)42 > [Cu(NO3)2]·(H2O)42 > [Cu(OH)2]·(H2O)42 > [CuSO4(H2O)3]·(H2O)42 > [CuNO3(H2O)4]+·(H2O)42 > [CuCN]+·(H2O)42. For the Cu(II) complex solutions with a halogen as ligands, the change order of 1000lnβ is [CuCl]+·(H2O)42 > [CuCl2]·(H2O)42 > [CuBr2]·(H2O)42 > [CuCl3]-·(H2O)42. The sequence of 1000lnβ for Cu(II) organic complex aqueous solutions is [Cu(HOC6H4COO)]+·(H2O)42 > [Cu(CH3CH2COO)]+·(H2O)42 > [Cu(COOHCOO)]+·(H2O)42. The calculation also found that for Cu(I) complex aqueous solutions, the difference in Cu isotope fractionation parameters (1000lnβ) between [CuCl2]-·(H2O)42 and [Cu(HS)2]-·(H2O)42 is relatively large. At 100 °C, the 1000lnβ of the two species are 1.14 and 1.55 (‱), respectively. The difference between the two could be reached up to 0.41 (‱). The Cu isotope fractionation parameter obtained with the "water droplet" method is also very different from the results of previous studies, which indicate that the Cu isotope fractionation behavior of the two is similar. At the same time, the exciting discovery is that the enrichment capacity of heavy Cu isotopes is significantly different between Cu(I) complex aqueous solutions and Cu(II) complex aqueous solutions. At 100 °C, the 1000lnβ of 6 Cu(I) complex aqueous solutions and 13 Cu(II) complex aqueous solutions ranged from 0.90 to 1.55 and 2.24 to 3.25(‱), respectively. It also shows that the REDOX reaction has a significant effect on the Cu isotope fractionation, especially in ore-forming fluids. Therefore, the ligand type is a factor that cannot be ignored when considering the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems. Whether the solvation effect of an aqueous solution is considered or not has a great influence on the numerical values of the final Cu isotope fractionation factors. Hence, the solvation effect of an aqueous solution is an essential determinant in the theoretical calculation of the Cu isotope fractionation factors for Cu-bearing complex solutions.

Insights into coordination and ligand trends of lanthanide complexes from the Cambridge Structural Database

Understanding lanthanide coordination chemistry can help develop new ligands for more efficient separation of lanthanides for critical materials needs. The Cambridge Structural Database (CSD) contains tens of thousands of single crystal structures of lanthanide complexes that can serve as a training ground for both fundamental chemical insights and future machine learning and generative artificial intelligence models. This work aims to understand the currently available structures of lanthanide complexes in CSD by analyzing the coordination shell, donor types, and ligand types, from the perspective of rare-earth element (REE) separations. We obtain four sets of lanthanide complexes from CSD: Subset 1, all Ln-containing complexes (49472 structures); Subset 2, mononuclear Ln complexes (27858 structures); Subset 3, mononuclear Ln complexes without cyclopentadienyl ligands (Cp) (26156 structures); Subset 4, Ln complexes with at least one 1,10-phenanthroline (phen) or its derivative as a coordinating ligand (2226 structures). The subsequent analysis of lanthanide complexes in these subsets examines the trends in coordination numbers and first shell distances as well as identifies and characterizes the ligands and donor groups. In addition, examples of Ln-complexes with commercially available complexants and phen-based ligands are interrogated in detail. This systematic investigation lays the groundwork for future data-driven ligand designs for REE separations based on the structural insights into the lanthanide coordination chemistry.

Structure Effects of Ligands in Gold-Ligand Complexes for Controlled Formation of Gold Nanoclusters.

Metal nanoclusters (NCs) are a special class of nanoparticles composed of a precise number of metal atoms and ligands. Because the proportion of ligands to metal atoms is high in metal NCs, the ligand type determines the physical properties of metal NCs. Furthermore, ligands presumably govern the entire formation process of the metal NCs. However, their roles in the synthesis, especially as factors in the uniformity of metal NCs, are not understood. It is because the synthetic procedure of metal NCs is highly convoluted. The synthesis is initiated by the formation of various metal-ligand complexes, which have different numbers of atoms and ligands, resulting in different coordinations of metal. Moreover, these complexes, as actual precursors to metal NCs, undergo sequential transformations into a series of intermediate NCs before the formation of the desired NCs. Thus, to resolve the complicated synthesis of metal NCs and achieve their uniformity, it is important to investigate the reactivity of the complexes. Herein, we utilize a combination of mass spectrometry, density functional theory, and electrochemical measurements to understand the ligand effects on the reactivity of AuI-thiolate complexes toward the reductive formation of Au NCs. We discover that the stability of the complexes can be increased by either van der Waals interactions induced by the long carbon chain of ligands or by non-thiol functional groups in the ligands, which additionally coordinate with AuI in the complexes. Such structural effects of thiol ligands determine the reduction reactivity of the complexes and the amount of NaBH4 required for the controlled synthesis of the Au NCs.

Divergent effects of olfactory receptors on transient receptor potential vanilloid 1 activation by capsaicin and eugenol.

We analyzed the effects of olfactory receptors (ORs) on transient receptor potential vanilloid 1 (TRPV1) activation using HEK293T cells co-expressing TRPV1 and OR51E1. We demonstrate here that the effect of OR51E1 on TRPV1 activation varies depending on the two TRPV1 ligands: capsaicin and eugenol. Notably, both of these ligands are vanilloid analogs. OR51E1 enhanced the response of TRPV1 to capsaicin but diminished that to eugenol. OR51E2 also showed similar effects. Based on the susceptibility to the OR's modulatory effects, various TRPV1 ligands could be classified into capsaicin and eugenol types. Activation of OR51E1 enhanced cAMP production. In addition, forskolin exhibited almost identical effects as ORs on TRPV1 responses to both types of ligands. These results suggest that OR51E1-induced cAMP elevation leads to a modification of TRPV1, presumably phosphorylation of TRPV1, which amplifies the susceptibility of TRPV1 to the two types of ligands differently.

A high-throughput lysosome trafficking assay guides ligand selection and elucidates differences in CD22-targeted nanodelivery

ABSTRACT Targeted nanoparticles offer potential to selectively deliver therapeutics to cells; however, their subcellular fate following endocytosis must be understood to properly design mechanisms of drug release. Here we describe a nanoparticle platform and associated cell-based assay to observe lysosome trafficking of targeted nanoparticles in live cells. The nanoparticle platform utilizes two fluorescent dyes loaded onto PEG-poly(glutamic acid) and PEG-poly(Lysine) block co-polymers that also comprise azide reactive handles on PEG termini to attach antibody-based targeting ligands. Fluorophores were selected to be pH-sensitive (pHrodo Red) or pH-insensitive (Alexafluor 488) to report when nanoparticles enter low pH lysosomes. Dye-labelled block co-polymers were further assembled into polyion complex micelle nanoparticles and crosslinked through amide bond formation to form stable nano-scaffolds for ligand attachment. Cell binding and lysosome trafficking was determined in live cells by fluorescence imaging in 96-well plates and quantification of red- and green-fluorescence signals over time. The platform and assay was validated for selection of optimal antibody-derived targeting ligands directed towards CD22 for nanoparticle delivery. Kinetic analysis of uptake and lysosome trafficking indicated differences between ligand types and the ligand with the highest lysosome trafficking efficiency translated into effective DNA delivery with nanoparticles bearing the optimal ligand.

Transforming waste into valuables: Preparation and evaluation of dual-ligand hydrophobic charge-induction chromatography using two poor performing ligands

In conventional chromatographic ligand screening, underperforming ligands are often dismissed. However, this practice may inadvertently overlook potential opportunities. This study aims to investigate whether these underperforming ligands can be repurposed as valuable assets. Hydrophobic charge-induction chromatography (HCIC) is chosen as the validation target for its potential as an innovative chromatographic mode. A novel dual-ligand approach is employed, combining two suboptimal ligands (5-Aminobenzimidazole and Tryptamine) to explore enhanced performance and optimization prospects. Various dual-ligand HCIC resins with different ligand densities were synthesized by adjusting the ligand ratio and concentration. The resins were characterized to assess appearance, functional groups, and pore features using SEM, FTIR, and ISEC techniques. Performance assessments were conducted using single-ligand mode resins as controls, evaluating the selectivity against human immunoglobulin G and human serum albumin. Static adsorption experiments were performed to understand pH and salt influence on adsorption. Breakthrough experiments were conducted to assess dynamic adsorption capacity of the novel resin. Finally, chromatographic separation using human serum was performed to evaluate the purity and yield of the resin. Results indicated that the dual-ligand HCIC resin designed for human antibodies demonstrates exceptional selectivity, surpassing not only single ligand states but also outperforming certain high-performing ligand types, particularly under specific salt and pH conditions. Ultimately, a high yield of 83.9 % and purity of 96.7 % were achieved in the separation of hIgG from human serum with the dual-ligand HCIC, significantly superior to the single-ligand resins. In conclusion, through rational design and proper operational conditions, the dual-ligand mode can revitalize underutilized ligands, potentially introducing novel and promising chromatographic modes.

Shape-Complementary Multicomponent Assembly of Low-Symmetry Co(III)Salphen-Based Coordination Cages.

While metal-mediated self-assembly is a popular technique to construct discrete nanosized objects, highly symmetric structures, built from one type of ligand at a time, are dominating reported systems. The tailored integration of a set of different ligands requires sophisticated approaches to avoid narcissistic separation or formation of statistical mixtures. Here, we demonstrate how the combination of three structure-guiding effects (metal-templated macrocyclization, additional bridging ligands and shape-complementarity) based on Co(III)salphen metal nodes allows for a rational and high-yielding synthesis of structurally complex, lantern-shaped cages with up to four differentiable bridges. Three new heteroleptic coordination cages based on dinuclear Co(III)salphen macrocycles were synthesized in a one-pot reaction approach and fully characterized, including single crystal X-ray analyses. One cage groups two of the same ligands, another two different ligands around a symmetric Co2-bis-salphen ring. In the most complex structure, this ring is unsymmetric, rendering all four connections between the two metal centers distinguishable. While heteroleptic assembly around Pd(II) nodes has been shown to be dynamic, beneficial for cage-to-cage transformations, assembly cascades and adaptive systems, the herein introduced cages based on kinetically more inert Co(III)salphen will be advantageous for applications in enzyme-like catalysis and molecular machinery that require enhanced structural and chemical stability.

Formkomplementäre Multikomponenten Assemblierung von Niedrigsymmetrischen Co(III)Salphen Koordinationskäfigen

AbstractWährend die metallvermittelte Selbstassemblierung eine beliebte Methode zur Synthese definierter Nanoobjekte ist, wird die Literatur von hochsymmetrischen Strukturen, aufgebaut aus jeweils einer Art von Liganden, dominiert. Die kontrollierte Integration einer Reihe verschiedener Liganden erfordert ausgeklügelte Ansätze, um eine narzisstische Trennung oder die Bildung statistischer Mischungen zu vermeiden. Hier zeigen wir, wie die Kombination von drei strukturleitenden Effekten (metallvermittelte Makrozyklisierung, zusätzliches Anbringen von Brückenliganden und Formkomplementarität) auf der Grundlage von Co(III)salphen‐Metallzentren die rationale Synthese von laternenförmigen Käfigen mit bis zu vier differenzierbaren Brücken ermöglicht. Drei neue heteroleptische Koordinationskäfige, basierend auf zweikernigen Co(III)salphen‐Makrozyklen, wurden in einer Eintopfreaktion synthetisiert und vollständig charakterisiert, einschließlich Einkristall‐Röntgenstrukturanalysen. Einer der Käfige gruppiert zwei gleiche Liganden, ein anderer zwei verschiedene Liganden um einen symmetrischen Co2‐Bis‐Salphen‐Ring. In der komplexesten Struktur ist dieser Ring unsymmetrisch, so dass alle vier Brücken zwischen den beiden Metallzentren unterscheidbar sind. Während sich heteroleptische Assemblies mit Pd(II)‐Zentren als dynamisch und vorteilhaft für Käfig‐zu‐Käfig‐Umwandlungen und adaptive Systeme erwiesen haben, werden die hier vorgestellten Käfige auf der Grundlage der kinetisch stabileren Co(III)‐Salphen Einheiten für Anwendungen, die eine erhöhte strukturelle und chemische Stabilität erfordern, von Vorteil sein, z.B. in der enzymähnlichen Katalyse und in molekularen Maschinen.

Neuroinflammation in dementia: A meta-analysis of PET imaging studies.

Dementia is a major public health challenge for aging societies worldwide. Neuroinflammation is thought to be a key factor in dementia development. The aim of this study was to comprehensively assess translocator protein (TSPO) expression by positron emission tomography (PET) imaging to reveal the characteristics of neuroinflammation in dementia. We used a meta-analysis to retrieve literature on TSPO expression in dementia using PET imaging technology, including but not limited to the quality of the study design, sample size, and the type of TSPO ligand used in the study. For the included studies, we extracted key data, including TSPO expression levels, clinical characteristics of the study participants, and specific information on brain regions. Meta-analysis was performed using R software to assess the relationship between TSPO expression and dementia. After screening, 12 studies that met the criteria were included. The results of the meta-analysis showed that the expression level of TSPO was significantly elevated in patients with dementia, especially in the hippocampal region. The OR in the hippocampus was 1.50 with a 95% CI of 1.09 to 1.25, indicating a significant increase in the expression of TSPO in this region compared to controls. Elevated levels of inflammation in the prefrontal lobe and cingulate gyrus are associated with cognitive impairment in patients. This was despite an OR of 1.00 in the anterior cingulate gyrus, indicating that TSPO expression in this region did not correlate significantly with the findings. The overall heterogeneity test showed I² = 51%, indicating moderate heterogeneity. This study summarizes the existing literature on TSPO expression in specific regions of the brain in patients with dementia, and also provides some preliminary evidence on the possible association between neuroinflammation and dementia. However, the heterogeneity of results and limitations of the study suggest that we need to interpret these findings with caution. Future studies need to adopt a more rigorous and consistent methodological design to more accurately assess the role of neuroinflammation in dementia, thereby providing a more reliable evidence base for understanding pathological mechanisms and developing potential therapeutic strategies.

Mitochondria-Targeting Metallodrugs for Cancer Therapy: Perspectives from Cell Death Modes.

Mitochondria, recognized as the cellular powerhouses, are indispensable organelles responsible for crucial cellular processes, such as energy metabolism, material synthesis, and signaling transduction. Their intricate involvement in a broad spectrum of diseases, particularly cancer, has propelled the exploration of mitochondria-targeting treatment as a promising strategy for cancer therapy. Since the groundbreaking discovery of cisplatin, the trajectory of research on the development of metal complexes have been marked by continuous advancement, giving rise to a diverse array of metallodrugs characterized by variations in ligand types, metal center properties, and oxidation states. By specifically targeting mitochondria, these metallodrugs exhibit the remarkable ability to elicit various programmed cell death pathways, encompassing apoptosis, autophagy, and ferroptosis. This review primarily focuses on recent developments in transition metal-based mitochondria-targeting agents, offering a comprehensive exploration of their capacity to induce distinct cell death modes. The aim is not only to disseminate knowledge but also to stimulate an active field of research toward new clinical applications and novel anticancer mechanisms.

Chiral P,N,N‐Ligands for Asymmetric Hydrogenation

AbstractThe chiral P,N,N‐ligands represented a new type of tridentate ligand developed in recent years and displayed wide utilities in asymmetric catalysis. In the past decades, numerous chiral P,N,N‐ligands with ferrocene, phenethylamine and spiro backbones were synthesized by addition of an aminopyridine, imidazole or diamines coordinating group. These chiral tridentate P,N,N‐ligands showed excellent performance in the ruthenium, iridium, manganese, or cobalt‐catalyzed asymmetric hydrogenations. A wide range of substrates, including simple ketones, α‐halogenated ketones, α‐hydroxy ketones, α‐ or β‐amino keto‐ ones, α‐, γ‐, or δ‐keto acids, α‐ or β‐keto amides, β‐ or δ‐keto esters, α‐ or β‐enones, olefins, imines, quinolines and indoles, could be hydrogenated to afford the corresponding chiral products with high yields and enantioselectivities. In this review, progress on the asymmetric hydrogenation of C=O, C=N, C=C bonds with chiral tridentate P,N,N‐ligands was summarized.

Surface complexation adsorption of Tl(III) by Fe and Mn (hydr)oxides

Thallium(III) (Tl(III)) is mobile in acidic environments and under ligand complexation, posing a potential threat to the environment and human health. The adsorption of Tl(III) on manganese and iron (hydr)oxides will affect its environmental mobility and engineering removal efficiency. However, the adsorption behavior and interfacial reaction mechanism of Tl(III) remain largely unknown. This study is the first to elucidate the surface complexation mechanism of Tl(III) on Fe/Mn (hydr)oxides and to investigate the adsorption behavior of Tl(III) under the influence of typical environmental ligands. Deprotonation of surface hydroxyl groups contributes to the increase in adsorption capacity for Tl(III) (δ-MnO2, 1619.93 mg g−1; α-FeOOH, 48.25 mg g−1; and α-Fe2O3, 58.66 mg g−1 from Langmuir thermodynamic fitting). Surface complexation modeling reveals tridentate complexation of Tl(III) on birnessite and monodentate complexation on iron (hydr)oxides. The anionic ligand strongly inhibits the adsorption of Tl(III) (up to 16.0 %–40.0 %) by complexing with Tl(III) and occupying the adsorption sites. In addition, HA also reduces the adsorption of Tl(III) by 8.2 %–23.2 % by exacerbating the aggregation and surface coating of the adsorbent particles. New insights into the binding mechanism of Tl(III) on Fe/Mn oxides can help to guide the development of efficient Tl(III) removal adsorbents.

Lipoxin A4 analogue, BML-111, reduces platelet activation and protects from thrombosis

Formyl peptide receptors (FPRs) are members of seven transmembrane G protein-coupled receptors superfamily that exhibit different responses based on the nature of stimulating ligand type. FPRs have been shown to be present in platelets and regulate their function. However, the effect of formyl peptide receptor 2 (FPR2/ALX) lipid ligands on platelets has not yet been addressed. Hence, we sought to study the role of FPR2/ALX ligand and lipoxin A4 lipid analogue, BML-111, in the modulation of platelet function and thrombus formation. Immunofluorescence microscopy showed subcellular distribution and peripheral mobilisation of FPR2/ALX in stimulated platelets. This variation in distribution was further confirmed using flow cytometry. BML-111 inhibited a range of platelet activities in a dose-dependent manner in response to several platelet agonists. This included aggregation, fibrinogen binding to integrin αIIbβ3, α-granule secretion, dense granule secretion, Ca2 + mobilisation and integrin αIIbβ3-mediated outside-in signaling. The selectivity of BML-111 for FPR2/ALX was confirmed using FPR2/ALX deficient mice in flow cytometry assays. In vitro thrombus formation was also inhibited by various concentrations of BML-111. Moreover, the levels of vasodilator stimulated phosphorylation (VASP-S157) increased significantly after BML-111 treatment in resting and stimulated platelets via protein kinase A (PKA) independently of cyclic adenosine monophosphate (cAMP) signaling. Together, our findings demonstrate the significance of BML-111 as a modulator of platelet function via FPR2/ALX and unravel the thrombo-protective potentials of BML-111 induced signaling against thrombo-inflammatory diseases.

Computational Comparative Study of the Binding of Americium with N-Donor Ligands.

The accessibility of multiple valence states of americium (Am) inspired redox-based protocols aimed at efficient separation of trivalent Am (Am3+) from trivalent lanthanides (Ln3+) alternative to the traditional liquid-liquid extraction. This requires an extensive understanding of the coordination chemistry of Am in its various accessible valence states in the aqueous phase. In this work, by means of DFT calculations, the coordination of AmIII-VI with five typical N-donor ligands, i.e., terpyridine (tpy), bispyrazinylpyridine (dpp), bistriazinylpyridine (BTP), bistriazinyl bipyridine (BTBP), and bistrazinyl phenanthroline (BTPhen), was studied in terms of energy and topological analysis. The results show that the exchange of aqua ligands of hydrated ions by N-donor ligands is an entropy-driven process and enthalpically unfavorable. Topological analysis suggests a distinct mechanism of BTP to modulate the redox potential of Am(III) in that BTP can assist the relay of the leaving electron of AmIII, while the other N-donor ligands can detain the oxidation of Am by offering their electron instead. This comparative study enriches our understanding of the coordination chemistry of high-valent Am with N-donor ligands and recommends the ligand design toward the modulation of redox potentials of hydrated Am(III) ions.

Structure, Thermal Properties and Photoluminescence of Terbium and Dysprosium Mixed‐Ligand Complexes with Dimethyl‐N‐Trichloroacetylamidophosphate and 2,2’‐Bipyridine

AbstractConsidering the growing interest in lanthanide‐based multifunctional materials two mixed‐ligand complexes [Ln(L)3bipy] (Ln=TbIII, DyIII) with carbacylamidophosphate (CAPh) type ligand – dimethyl‐N‐trichloroacetylamidophosphate (HL) and additional bidentate ligand 2,2’‐bipyridine (bipy) were obtained and studied by X‐ray diffraction study, thermal gravimetric analysis, and luminescence spectroscopy. The obtained complexes are monomeric and isostructural with earlier reported europium analog and crystallizes in the monoclinic system (space group C2/c). They are stable during long‐term storage for at least a couple of years as well as thermally stable up to nearly 200 °C. Both complexes exhibit f–f luminescence upon excitation into the 2,2’‐bipyridine absorption band, being emitters of green (TbIII) and yellow (DyIII) light. The luminescence intensity of the obtained complexes decreases constant exposure to UV radiation for several hours and then stays constant for at least till 32 h.

Influences of coordination structures on the electronic properties of Zn ion and the adsorption of O-containing and S-containing molecules

Ligands in minerals have an important effect on the chemical properties of metal ions. The electronic properties of Zn ions formed by O and S ligands have been studied using density functional theory (DFT), and the interaction strength between O and S-containing molecules and Zn ions has been analyzed. The results show that the electronic properties of Zn ions may be influenced by the type of ligands, the number of ligands, and the distance between ligands and Zn ions. The adsorption capacity of zinc ions decreased with an the in increase ligand coordination number, but increased with an increase in the distance between the ligand and zinc ion. The adsorption of O- and S-containing molecules on sphalerite smithsonite and hemimorphite was then studied. It was indicated that O-containing molecules had a strong collecting ability for sphalerite, smithsonite and hemimorphite, but the adsorption capacity of S-containing molecules was weaker than that of O-containing molecules. The influence of water molecules on the adsorption behavior of O- and S-containing molecules was studied. The results of the calculations show that the relationship between H2O and O-containing sulfur-containing molecules is competitive adsorption on the surface of sphalerite smithsonite and hemimorphite. Adsorption of water molecules can reduce the adsorption energy of O-containing and S-containing molecules on mineral surfaces.

Supramolecular Coordination Complexes for Synergistic Cancer Therapy.

Supramolecular coordination complexes (SCCs) are predictable and size-tunable supramolecular self-assemblies constructed through directional coordination bonds between readily available organic ligands and metallic receptors. Based on planar and 3D structures, SCCs can be mainly divided into two categories: metallacycles (e.g., rhomboidal, triangular, rectangular, and hexagonal) and metallacages (e.g., tetrahedral, hexahedral, and dodecahedral). The directional coordination bonds enable the efficient formation of metallacycles and metallacages with well-defined architectures and geometries. SCCs exhibit several advantages, including good directionality, strong interaction force, tunable modularity, and good solution processability, making them highly attractive for biomedical applications, especially in cellular imaging and cancer therapy. Compared with their molecular precursors, SCCs demonstrate enhanced cellular uptake and a strengthened tumor accumulation effect, owing to their inherently charged structures. These properties and the chemotherapeutic potential inherent to organic platinum complexes have promoted their widespread application in antitumor therapy. Furthermore, the defined structures of SCCs, achieved via the design modification of assembly elements and introduction of different functional groups, enable them to combat malignant tumors through multipronged treatment modalities. Because the development of cancer-treatment methodologies integrated in clinics has evolved from single-modality chemotherapy to synergistic multimodal therapy, the development of functional SCCs for synergistic cancer therapy is crucial. While some pioneering reviews have explored the bioapplications of SCCs, often categorized by a specific function or focusing on the specific metal or ligand types, a comprehensive exploration of their synergistic multifunctionality is a critical gap in the current literature.In this Account, we focus on platinum-based SCCs and their applications in cancer therapy. While other metals, such as Pd-, Rh-, Ru-, and Ir-based SCCs, have been explored for cancer therapy by Therrien and Casini et al., platinum-based SCCs have garnered significant interest, owing to their unique advantages in antitumor therapy. These platinum-based SCCs, which enhance antitumor efficacy, are considered prominent candidates for cancer therapies owing to their desirable properties, such as potent antitumor activity, exceptionally low systemic toxicity, active tumor-targeting ability, and enhanced cellular uptake. Furthermore, diverse diagnostic and therapeutic modalities (e.g., chemotherapy, photothermal therapy, and photodynamic therapy) can be integrated into a single platform based on platinum-based SCCs for cancer therapy. Consequently, herein, we summarize our recent research on platinum-based SCCs for synergistic cancer therapy with particular emphasis on the cooperative interplay between different therapeutic methods. In the Conclusions section, we present the key advancements achieved on the basis of our research findings and propose future directions that may significantly impact the field.

Designing Nickel-based catalysts for the hydrogenation of CO2 under Ambient conditions: A computational study

Recent developments, industrialization, and modernization lead to production of more and more pollutants (such as CO2: ∼ 417.06 ppm) and such rapid growth of CO2 level results in global warming and the greenhouse effect. So, it is essential to conduct research on converting CO2 into fuels using carbon-neutral energy. Recent research on molecular catalysts has improved the rates of converting CO2 to formate. However, these catalysts require extremely high temperatures and pressures and are made of expensive metals like iridium, ruthenium, and rhodium. Herein, DFT-based computational studies have been performed on the catalytic hydrogenation of CO2 by different Ni(II) complexes in ambient conditions. Using state-of-the-art calculations, we demonstrate how the geometry and spin states of Ni(II) complexes containing different types of ligands affect their catalytic role in CO2 hydrogenation. It has been reported that hydride transfer is the most crucial step for such kind of hydrogenation reaction. We start with previously synthesised Ni-bis(diphosphine) complexes of type NiP4 and by extrapolating the concept, we propose a novel kind of Ni-PNP complex with a significantly lower hydride transfer barrier. We also calculate the hydricities of the nickel hydride complexes in order to correlate these thermodynamic parameters with the kinetic barrier of hydride transfer.

Actively Targeted Nanomedicines: A New Perspective for the Treatment of Pregnancy-Related Diseases.

More than 20% of pregnant women experience serious complications during pregnancy, that gravely affect the safety of both the mother and the child. Due to the unique state of pregnancy, medication during pregnancy is subject to various restrictions. Nanotechnology is an emerging technology that has been the focus of extensive medical research, and great progress has recently been made in developing sensitive diagnostic modalities and efficient medical treatment. Accumulating evidence has shown that nanodrug delivery systems can significantly improve the targeting, reduce the toxicity and improve the bioavailability of drugs. Recently, some actively targeted nanomedicines have been explored in the treatment of pregnancy-related diseases. This article reviews common types of nanocarriers and active targeting ligands in common pregnancy-related diseases and complications such as preeclampsia, preterm birth, fetal growth restriction, and choriocarcinoma. Finally, the challenges and future prospects in the development of these nanomaterials are discussed, with the aim of providing guidance for future research directions.