Types Of Ligands Research Articles

Sustainable Hydrogen Production by Glycerol and Monosaccharides Catalytic Acceptorless Dehydrogenation (AD) in Homogeneous Phase.

In the quest for sustainable hydrogen production, the use of biomass-derived feedstock is gaining importance. Acceptorless Dehydrogenation (AD) in the presence of efficient and selective catalysts has been explored worldwide as a suitable method to produce hydrogen from hydrogen-rich simple organic molecules. Among these, glycerol and sugars have the advantage of being cheap, abundant, and obtainable from fatty acid basic hydrolysis (biodiesel industry) and from biomass by biochemical and thermochemical processing, respectively. Although heterogeneous catalysts are more widely used for hydrogen production from biomass-based feedstock, the harsh reaction conditions applied limit applicability due to deactivation of active sites due to coking of carbonaceous materials. Moreover, heterogeneous catalyst are more difficult to fine-tune than homogeneous counterparts, and the latter also allow for high process selectivities under milder conditions. The present Concept article summarizes the main features of the most active homogeneous catalysts reported for glycerol and monosaccharides AD. In order to directly compare hydrogen production efficiencies, the choice of literature works was limited to reports where hydrogen was clearly quantified by yields and turnover numbers (TONs). The types of transition metals and ligands is discussed, together with a perspective view on future challenges of homogeneous AD reactions for practical applications.

Engineering the Coordination Environment in the Silver(I)- and Ruthenium(II)-N-Heterocyclic Carbene Complexes in Instigating the Electrocatalytic Hydrogen Evolution Reaction.

The quest for cost-efficient and high-performance electrocatalysts towards electrocatalytic water splitting is a key and an interdisciplinary area of study. Considerable progress is being driven by developments in the field of energy research. In a fundamental study, we have synthesized NHC precursors (6 and 7) and corresponding metal-NHC complexes of silver(I)- (8 and 9) and ruthenium(II)- (10 and 11) of a N-heterocyclic carbene-based ligand type incorporating coumarins. These NHC precursors and metal-NHC complexes were characterized through various analytical and spectral techniques. The silver(I)-NHC complexes 8 and 9 displayed a linear coordination geometry with a center of inversion, which is evidenced by the single-crystal X-ray diffraction technique. Both the series of complexes were assessed for their efficacies in the hydrogen evolution reaction (HER). The results demonstrated that attributed to its peculiar coordination geometry, high electrical conductivity the silver(I)- and ruthenium(II)-NHC complexes exhibited exemplary electrocatalytic activity. Activities of the hydrogen evolution reaction on two differently modified electrode substrates with metal-NHC complexes have been studied. To attain the benchmark HER current density of 10 mA cm-2, in 1.0 M KOH, an overpotential of -375 to -527 mV vs RHE was required for the metal-NHC complexes. Based on the analysis of the Tafel slope values, the rate-determining step was the adsorption of hydrogen as investigated in the potential window. The molecular electrocatalyst 10 presented a superior stability and maintained the electrocatalytic activity for a duration of 18 h with complex 8 and 24 h with respect to complex 10 in 1.0 M KOH. Apace with these studies, hydrogen oxidation studies were examined in 0.5 M H2SO4 by a substantial current density at the platinum ring electrode. This research offers feasible guidance for developing organometallic-based molecular electrocatalysts with good electrocatalytic performance.

Biased activation of the vasopressin V2 receptor probed by molecular dynamics simulations, NMR and pharmacological studies

G protein-coupled receptors (GPCRs) control critical cell signaling. Their response to extracellular stimuli involves conformational changes to convey signals to intracellular effectors, among which the most important are G proteins and β-arrestins (βArrs). Biased activation of one pathway is a field of intense research in GPCR pharmacology. Combining NMR, site-directed mutagenesis, molecular pharmacology, and molecular dynamics (MD) simulations, we studied the conformational diversity of the vasopressin V2 receptor (V2R) bound to different types of ligands: the antagonist Tolvaptan, the endogenous unbiased agonist arginine-vasopressin, and MCF14, a partial Gs protein-biased agonist. A double-labeling NMR scheme was developed to study the receptor conformational changes and ligand binding: V2R was subjected to lysine 13CH3 methylation for complementary NMR studies, whereas the agonists were tagged with a paramagnetic probe. Paramagnetic relaxation enhancements and site-directed mutagenesis validated the ligand binding modes in the MD simulations. We found that the bias for the Gs protein over the βArr pathway involves interactions between the conserved NPxxY motif in the transmembrane helix 7 (TM7) and TM3, compacting helix 8 (H8) toward TM1 and likely inhibiting βArr signaling. A similar mechanism was elicited for the pathogenic mutation I130N, which constitutively activates the Gs proteins without concomitant βArr recruitment. The findings suggest common patterns of biased signaling in class A GPCRs, as well as a rationale for the design of G protein-biased V2R agonists.

Ligands of Nanoparticles and Their Influence on the Morphologies of Nanoparticle-Based Films.

Nanoparticle-based thin films are increasingly being used in various applications. One of the key factors that determines the properties and performances of these films is the type of ligands attached to the nanoparticle surfaces. While long-chain surfactants, such as oleic acid, are commonly employed to stabilize nanoparticles and ensure high monodispersity, these ligands often hinder charge transport due to their insulating nature. Although thermal annealing can remove the long-chain ligands, the removal process often introduces defects such as cracks and voids. In contrast, the use of short-chain organic or inorganic ligands can minimize interparticle distance, improving film conductivity, though challenges such as incomplete ligand exchange and residual barriers remain. Polymeric ligands, especially block copolymers, can also be employed to create films with tailored porosity. This review discusses the effects of various ligand types on the morphology and performance of nanoparticle-based films, highlighting the trade-offs between conductivity, structural integrity, and functionality.

Ghrelin Modulates Voltage-Gated Ca2+ Channels through Voltage-Dependent and Voltage-Independent Pathways in Rat Gastric Vagal Afferent Neurons.

The orexigenic gut peptide ghrelin is an endogenous ligand for the growth hormone secretagogue receptor type 1a (GHSR1a). Systemic ghrelin administration has previously been shown to increase gastric motility and emptying. While these effects are known to be mediated by the vagus nerve, the cellular mechanism underlying these effects remains unclear. Therefore, the purpose of the present study was to investigate the signaling mechanism by which GHSR1a inhibits voltage-gated Ca2+ channels in isolated rat gastric vagal afferent neurons using whole-cell patch-clamp electrophysiology. The ghrelin pharmacological profile indicated that Ca2+ currents were inhibited with a log (Ic50) = -2.10 ± 0.44 and a maximal inhibition of 42.8 ± 5.0%. Exposure to the GHSR1a receptor antagonist (D-Lys3)-GHRP-6 reduced ghrelin-mediated Ca2+ channel inhibition (29.4 ± 16.7% vs. 1.9 ± 2.5%, n = 6, P = 0.0064). Interestingly, we observed that activation of GHSR1a inhibited Ca2+ currents through both voltage-dependent and voltage-independent pathways. We also treated the gastric neurons with either pertussis toxin (PTX) or YM-254890 to examine whether the Ca2+ current inhibition was mediated by the Gα i/o or Gα q/11 family of subunits. Treatment with both PTX (Ca2+ current inhibition = 15.7 ± 10.6%, n = 8, P = 0.0327) and YM-254890 (15.2 ± 11.9%, n = 8, P = 0.0269) blocked ghrelin's effects on Ca2+ currents, as compared with control neurons (34.3 ± 18.9%, n = 8). These results indicate GHSR1a can couple to both Gα i/o and Gα q/11 in gastric vagal afferent neurons. Overall, our findings suggest GHSR1a-mediated inhibition of Ca2+ currents occurs through two distinct pathways, offering necessary insights into the cellular mechanisms underlying ghrelin's regulation of gastric vagal afferents. SIGNIFICANCE STATEMENT: This study demonstrated that in gastric vagal afferent neurons, activation of GHSR1a by ghrelin inhibits voltage-gated Ca2+ channels through both voltage-dependent and voltage-independent signaling pathways. These results provide necessary insights into the cellular mechanism underlying ghrelin regulation of gastric vagal afferent activity, which may benefit future studies investigating ghrelin mimetics to treat gastric motility disorders.

A 36-nucleus silver-thiolate cluster encapsulating double sulfates and co-protected by cyclen

New type of cyclic multi-dentate ligand named, Cyclen (1,4,7,10-tetraazacyclododecane, [12]aneN4), was successfully introduced onto the surface of a 36-nucleus double sulfates templated silver-thiolate cluster [(SO4)2@Ag36(SPhtBu)24(cyclen)4(CF3CO2)6(OH)2] (1). The nanocluster was investigated and characterized by single-crystal X-ray crystallography (SXRD), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), ultraviolet−visible (UV) spectroscopy, and photoluminescence (PL). The cluster shows very good solution stability in four different solvents and excellent thermal stability in the solid-state. It shows orange-red emission in EtOAc/THF/CH2Cl2/CHCl3 at 77 K. The lifetime of 1 in four different solvents is over 140 μs, and the highest quantum yield of 1 is 25.46 %. The nanocluster shows temperature-dependent photoluminescence properties in different solvents, which make them potential candidates in the fields of optical devices for future applications.

Modulating the Anticancer Activity of Square‐Planar Platinum (II) Complex by Its Chelated Diphosphine

ABSTRACTThis work reports the preparations and anticancer activities of a set of platinum (II) complexes. Two types of bidentate ligands, azadiphosphine (PNP) and diphosphine (PP), were applied to afford different kinds of platinum centers, the homoleptic complexes, [Pt (PNP)2]2+ (1 and 2) and [Pt (PP)2]2+ (4), and the hybrid complex, [Pt (PNP)(PP)]2+ (3). All these complexes are characterized by various analytical techniques, and their structures were validated using single‐crystal X‐ray diffraction analysis. Notably, the stability of the complexes 1–4 is differentiated both in phosphate‐buffered saline (PBS) and in the culture media (RPMI‐1640), relative to the type of coordinated diphosphine ligands, specifically, the more PNP ligands, the less stability. The bite angles of P‐Pt‐P bonds in 1–4 would be reliant on their stability, so that complexes 1 and 2 with small bite angles tend to be labile. A mechanistic understanding on the decomposition of 2 is proposed with the aid of mass analysis. As a result, their anticancer activities should be also associated with their stability so that the chelated ligands, with more PNP ligands, lead to more cytotoxicity. Mechanistically, the poisonous platinum (II) derivatives of complex 2 should interact with the nucleus DNA, whereas the intact complex 4 is not traceable, confirming from a γ‐H2AX‐related immunofluorescence staining kit. Additionally, complex 2 exhibits severe toxicity toward several cancer cells as well as a normal cell. Furthermore, complex 2 has inhibited the formation and viability of three‐dimensional T24 mammospheres, reminding it of a promising candidate for anticancer treatments. Overall, the present work provides a way for the systematic investigation to elucidate how a bidentate diphosphine ligand modulates the stability and the anticancer activities of the corresponding square‐planner platinum (II) complex.

Synthesis and Photochemical Properties of Heterometallic Ti-Cu Ring Clusters Constructed from Myo-Inositol Ligand.

Incorporating heterometals into titanium-oxygen clusters represents an effective approach to adjusting the band gap and absorption properties. Herein, a family of heterometallic Ti-Cu clusters was synthesized under solvothermal conditions. The unique structural feature of these clusters is the formation of ring clusters with myo-inositol ligands serving as structure-directing ligands. The myo-inositol ligand, as a typical polyol ligand, demonstrates flexible and distinctive coordination modes capable of chelating up to eight transition metal ions simultaneously. Compounds 4 and 5 show significant absorption in the visible region, indicating that the incorporation of Cu ions can efficiently tune the band gap of titanium-oxygen clusters.

The β2-adrenergic biased agonist nebivolol inhibits the development of Th17 and the response of memory Th17 cells in an NF-κB-dependent manner.

Adrenergic receptors regulate metabolic, cardiovascular, and immunological functions in response to the sympathetic nervous system. The effect of β2-adrenergic receptor (AR) as a high expression receptor on different subpopulations of T cells is complex and varies depending on the type of ligand and context. While traditional β2-AR agonists generally suppress T cells, they potentially enhance IL-17A production by Th17 cells. The effects of pharmacological drugs that count as biased agonists of AR like nebivolol are not completely understood. We investigated the impact of nebivolol on human memory CD4+ T (Th1, Th2, Th17) cells and polarized naive Th17 cells, highlighting its potential for IL-17A suppression via a non-canonical β2-AR cell signaling pathway. The effects of nebivolol were tested on healthy human peripheral blood mononuclear cells, purified memory Th cells, and polarized naive Th17 cells activated with anti-CD3/anti-CD28/anti-CD2 ImmunoCult reagent. IFN-γ, IL-4, and IL-17A, which are primarily derived from Th1, Th2, and Th17 cells, respectively, were quantified by ELISA and flow cytometry. IL-10 was measured by ELISA. Gene expression of RORC, ADRB1, ADRB2, and ADRB3 was evaluated by qPCR. The ADRB2 gene was knocked out in memory Th cells using CRISPR/Cas9. Protein expression of phosphorylated serine133-CREB and phosphorylated NF-κB p65 was assessed by Western blot. Proliferation was assessed by fluorescent dye loading and flow cytometry. Nebivolol treatment decreased IL-17A and IFN-γ secretion by activated memory Th cells and elevated IL-4 levels. Nebivolol reduced the proportion of IL-17A+ Th cells and downregulated RORC expression. Unlike the β2-AR agonist terbutaline, nebivolol inhibited the shift of naive CD4+ T cells toward the Th17 phenotype. IL-10 and the proliferation index remained unchanged. Nebivolol-treated β2-knockout memory Th cells showed significant inhibition of β2-AR-mediated signaling, evidenced by the absence of IL-17A suppression compared to controls. Phosphorylation of the NF-κB p65 subunit was inhibited by nebivolol, but CREB phosphorylation was not changed, suggesting a selective transcriptional control. The findings demonstrate that nebivolol acts through a β2-AR-mediated signaling pathway, as a distinctive anti-inflammatory agent capable of selectively shifting Th17 cells and suppressing the phosphorylation of NF-κB. This highlights nebivolol's potential for therapeutic interventions in chronic autoimmune conditions with elevated IL-17A levels.

Algorithm-Driven Robotic Discovery of Polyoxometalate-Scaffolding Metal-Organic Frameworks.

The experimental exploration of the chemical space of crystalline materials, especially metal-organic frameworks (MOFs), requires multiparameter control of a large set of reactions, which is unavoidably time-consuming and labor-intensive when performed manually. To accelerate the rate of material discovery while maintaining high reproducibility, we developed a machine learning algorithm integrated with a robotic synthesis platform for closed-loop exploration of the chemical space for polyoxometalate-scaffolding metal-organic frameworks (POMOFs). The eXtreme Gradient Boosting (XGBoost) model was optimized by using updating data obtained from the uncertainty feedback experiments and a multiclass classification extension based on the POMOF classification from their chemical constitution. The digital signatures for the robotic synthesis of POMOFs were represented by the universal chemical description language (χDL) to precisely record the synthetic steps and enhance the reproducibility. Nine novel POMOFs including one with mixed ligands derived from individual ligands through the imidization reaction of POM amine derivatives with various aldehydes have been discovered with a good repeatability. In addition, chemical space maps were plotted based on the XGBoost models whose F1 scores are above 0.8. Furthermore, the electrochemical properties of the synthesized POMOFs indicate superior electron transfer compared to the molecular POMs and the direct effect of the ratio of Zn, the type of ligands used, and the topology structures in POMOFs for modulating electron transfer abilities.

Chiral Self-Assembly of Twisted Prisms, Cuboids, and Polyhedral Capped Cages with Tartrate Ligands.

Homochiral triangular prisms, cuboid cages, and capped polyhedral cages are successfully synthesized via coordination-driven self-assembly. Typical tartrate ligands demonstrated notable torsional flexibility and variable coordination numbers, allowing for diverse coordination patterns, including saturated chelation and terminal mono-coordination with half-sandwich rhodium and iridium fragments. The ligand lengths, molar ratios, and metal vertices are meticulously designed and fine-tuned to yield chiral cages with entirely distinct architectures. Tartrate ligand exhibits abundant hydrogen bonding interactions and chiral induction capabilities, these supramolecular assemblies are characterized by single-crystal X-ray diffraction, nuclear magnetic resonance, and circular dichroism spectroscopy. An efficient method is developed for constructing chiral structurally versatile cage-like entities, facilitating self-assembly in complicated multi-component systems.

A novel trialkyl phosphate – Ionic liquid mixture for an efficient separation of Lithium ion from its acidic feed solution

Separation of Lithium ion (Li+) using conventional non-crown type ligands through solvent extraction process is a challenging task and can only be feasible by tuning the organic phase with an additional polar environment. In this context, we have projected an extracting system containing a traditional trialkyl phosphate (T(alk)P): Tri-iso-amyl phosphate (TiAP) containing a minimal amount of ionic liquid (IL): [C4mpip][NTf2] (1-butyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide) for the efficient extraction and separation of Li+ from its hydrochloric acid feed. The extraction performances pertaining various experimental parameters were realized to explore the solvent potentiality of TiAP/[C4mpip][NTf2] towards Li+ coordination. Involvement of two ligand molecules in extraction in presence of 10 % (v/v) IL diluent offers fast extraction kinetics and turns the extraction mechanism into a cation exchange pathway, which was further examined by using different classes of ILs in conjunction with TiAP for Li+ uptake. The selectivity of Li+ over other alkali (or alkaline earth) metal ions was investigated to highlight the affinity of the proposed IL system towards Li+. Extraction scenario in TiAP phase was compared with that in TBP phase containing same IL to bring out the efficacy of the proposed IL system. The stripping performance of Li+ from the loaded organic phase was studied using an acid solution to establish the sustainability of the proposed extraction process.

A highly selective and recyclable fluorescent sensor based on a Salamo-Salen-Salamo type ligand for continuous detection of Al3+ and phosphates in drug

In this work, a fluorescence chemical sensor continuous detection Al3+ and phosphates by a Salamo-Salen-Salamo type compound (SL) was employed. The sensor continuously recognized Al3+ and phosphates with good selectivity and fast response time, and a low limit of detection of 0.25 μΜ and 0.96 μM, at the same time accompanied by a naked-eye identification specificity. The detection mechanism of SL towards Al3+ is due to the chelating fluorescence enhancement effect and ICT effect, and continuously towards phosphates is due to the collapse of the SL-Al3+ and coordination interaction between Al3+ and phosphates, by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, other spectral characterization and DFT calculation as evidence. In addition, the sensor had good recyclability and reusability. The distribution of Al3+ and phosphates in zebrafish cells was effectively monitored by confocal microscopy based on the good biocompatibility and tissue permeability of SL. Furthermore, the feasibility of using sensor SL to detect the content of Al3+ and phosphate ions in certain drugs was quantitatively analyzed through experiments. It was found SL had a good result in practical application.

Chiral Self-Sorting Process With C2 Symmetric Bisimidazoline Ligands.

We have studied the coordination chemistry of chiral imidazoline-based C2-symmetric ligands with zinc (II) and copper (II). Two types of bisimidazoline ligands were studied, one with the free amine (BIM-H) and the other with the amine protected by a toluene sulfonyl group in position 6 (BIM-Ts). The complexes formed were isolated, purified, and characterized, in particular by X-ray diffraction studies and CD in the case of the enantiopure complexes. By playing with the choice of ligand system (enantiopure or racemate), we were able to show that the selective formation of homoleptic and heteroleptic metal complexes can be controlled by means of the chiral molecular instruction of bisimidazoline ligands.

Instrument-free detection of natamycin in beer and wastewater based on Eu-MOF ratiometric fluorescence response

Excessive intake of natamycin (NAT) is harmful to human health, so it is of great significance and necessity to effectively detect the content of NAT in food. In this study, we synthesized a dual-emission fluorescence probe, Eu@UiO-66(OH)2/(COOH)2, which exhibited emission peaks at 439nm and 614nm. This probe was obtained through the europium post-modification of UiO-66 type metal-organic frameworks (Eu-MOFs), which consisted of two types of ligands, 2, 5-dihydroxyterephthalic acid and pyromellitic acid. As expected, this probe Eu@UiO-66(OH)2/(COOH)2 can specifically respond to NAT with distinguishable ratiometric fluorescence changed from purple-red to blue with low limit of detection (0.15μM, approximately 0.10mg/kg), wide linear range (0-100μM), fast response (less than 1min), good selectivity and interference resistance. Based on the ratiometric fluorescence responsiveness, Eu@UiO-66(OH)2/(COOH)2 had been successfully used for the quantitative detection of NAT in wastewater, beer, yoghurt, and juice, demonstrating good recovery through smartphone-based colorimetric analysis. Thus, this work provides a ratiometric fluorescent probe for rapid, instrument-free and on-site detection of NAT in real samples such as beverage and environmental water.

A Meso Butterfly-Like Ce(III)-Containing Antimonotungstate with Catalytic Activity for Synthesizing Isoindolinones.

A unique meso Ce(III)-containing antimonotungstate, {Na(OAc)(H2O)2[Ce4(tar)(Htar)2(Sb2W21O72)2(H2O)7]}244- (Ce4tar3; H4tar = tartaric acid), consisting of two enantiomeric parts with a butterfly-like configuration, was successfully synthesized by a one-pot in situ method and characterized. The coordination of d- or l-tar ligands induced the formation of Dawson-like {Ce2Sb2W21} with right or left configurations, thereby determining the d/l configurations of {Na(OAc)(H2O)2[Ce4(tar)(Htar)2(Sb2W21O72)2(H2O)7]}22-. Carboxyl groups link these two enantiomeric parts with Ce(III) ions from each other around the symmetric center of the P1̅ space group. The three types of tar ligands exhibit distinct coordination modes, and all coordinate with at least one W(VI) atom using one carboxylate oxygen atom and one α-OH. Ce4tar3 represents the largest case among those meso-dl-tar-functionalized polyoxometalates. Furthermore, Ce4tar3 exhibits excellent catalytic activity for synthesizing isoindolinones via the three-component reaction of 2-acetylbenzoic acids, amines, and phosphine oxides.

Can Physicochemical Properties Alter the Potency of Aeroallergens? Part 2 - Impact of Physicochemical Properties.

A holistic perspective on how physicochemical properties modulate the allergenicity of proteins has recently been performed for food allergens, launching the challenge of a similar analysis for aeroallergens. After a first review on aeroallergen classification into protein families (Part 1), this second part (Part 2) will exploit the impact of physicochemical properties (abundance/biological function, protein structure/presence of post-translational modifications, ligand/cofactor/lipid-binding) on inhalant protein allergenicity. The abundance linked to biological function is correlated with increased allergenic risk for most protein families, while the loss of structural integrity with consequent destruction of conformational epitopes is well linked with decreased allergenicity. Ligand-binding effect totally depends on the ligand type being highly variable among aeroallergens. Knowledge about the physicochemical properties of aeroallergens is still scarce, which highlights the need for research using integrated approaches (in silico and experimental) to generate and analyze new data on known/new aeroallergens.

Synthesis, crystal structure, and thermal properties of energetic complex Cu(II) and Ag(I) based on 3-amino-4-(4,5-diamino-1,2,4-triazole-3yl)-furazan

High nitrogen compounds have received much attention due to their great potential as high energy density materials, and the selection of high nitrogen heterocyclic rings as ligands for energetic coordination compounds (ECCs) play a leading role in regulating the energy properties of ECCs. Furazan is rarely used as a building block for the development of high-energy metal ligands. In this study, a new type of high nitrogen ligand 3-amino-4-(4,5-diamino-1,2,4-triazole-3yl)-furazan (ATF) was selected and four kinds of high energy coordination polymers [Cu(II)(ATF)2·4H2O](NO3)2·2H2O (1), [Cu(II)(ATF)2·4H2O](ClO4)2·2H2O (2), [Ag(I)(ATF)2]ClO4·H2O (3) and [Ag(I)(ATF)2NO3] (4) were prepared by water solvent volatilization method and characterized for the first time. The single crystal XRD confirmed that there were abundant hydrogen bond interactions in the four complexes, resulting in dense aggregation with densities of 1.680 ∼ 2.089 g·cm−3. Meanwhile, theoretical calculations show that the detonation velocities of the four ECCs, 7578 ∼ 8192 m·s−1. In terms of thermal stability, the decomposition temperatures of the four ECCs (Td: 253 ∼ 288 °C) showed higher thermal stability during the rapid heating process than the reported ECCs (Cu(PZCA)2(ClO4)2, [Ag+(daf)NO3−]n and CHHP). Both shock and friction sensitivities are greater than 20 J and 300 N. This new structural motif is a promising high-energy material. Moreover, they can promote the combustion decomposition of ammonium perchlorate (AP) well, and the promotion effect of 1 and 2 is better than that of 3 and 4. In the field of explosives and propellants, four ECCs can be attractive candidates.

A comprehensive review on the development of chiral Cu, Ni, and Zn complexes as pharmaceutical agents over the past decades: Synthesis, molecular structure and biological activity.

Chirality is a fundamental and widespread geometric structural property in living organisms that most biomacromolecules including nucleic acids, proteins and enzymes, possess. Consequently, the development of chiral drugs capable of binding specific targets have gradually gained wide attention in recent decades due to their selective effects on a broad spectrum of biological events ranging from cell metabolism to cell fate. In this context, the synthesis of chiral compounds as promising therapeutic candidates has assumed a major role in drug discovery. Among them, chiral metal complexes have attracted considerable interest due to their unique and intriguing structural features that could enable overcoming side effects and drug-resistance phenomena of metal-based drugs currently in the market such as cisplatin. In the current scenario, an in-depth overview of non-platinum chiral complexes needs to be presented and carried forward. Therefore, in this perspective article, an update of the scientific development of bioactive chiral copper, zinc and nickel complexes have been reported since they have not been thoroughly reviewed so far. Specifically, we focused the article mainly on metal complexes containing chiral ligands (type 2 chirality) as in literature they are more numerous than those with chirality at the metal center (type 1 chirality). Herein, not only their biological activity but also their mechanism of action is summarized. Furthermore, in the final section of the article we have highlighted copper-based complexes as those with a superior biological activity profile and greater prospects for development as a drug.

Controlling the growth mode of Au depositing on Au nanobipyramids via ligand coverage for SERS enhancement

Gold deposition on Au nanoparticles is a common method to control the shape and further modify the properties of nanoparticles as their properties have a strong correlation with their nanostructures. For Au nanobipyramid (Au NBP), it has advantages such as the enhancement of electric field and a higher tunability in plasmon wavelength than the Au nanorod and thus owns a greater potential in shape control. In this paper, we demonstrate a scheme of depositing Au on the surface of Au NBP with the presence of a type of ligand 2-mercaptobenzoimidazole-5-carboxylic acid (MBIA) to synthesize Au NBP@Au dimers. The growth mode of Au depositing on Au NBP can be controlled by the coverage of MBIA. As the coverage is low, with a concentration of MBIA below 0.4 mM, the rough core–shell nanostructure is synthesized; However, as the coverage is high, with a concentration of MBIA over 0.8 mM, gold deposition may form islands on the surface of Au NBP. The SERS performance of Au depositing on Au NBP can also be enhanced by growth mode. For the rough-surface core–shell growth mode, the enhancement is more significant as the EF is improved from 3.5 × 105 to 1.06 × 106 than the islands-growing growth mode due to the coupling between core and shell. And our results show that with multiple types of nanosturctures easy to obtained by changing modified ligand coverage, the controlled growth has a great potential in the dimer design and SERS enhancement using Au NBP.