Chiral Canoe-Like Pd0 or Pt0 Alloyed Copper Alkynyl Nanoclusters Display Near-Infrared Luminescence.

Alloying nanoclusters (NCs) has emerged as a widely explored and versatile strategy for tailoring tunable properties, facilitating in-depth atomic-level investigations of structure-property correlations. In this study, we have successfully synthesized six atomically precise copper NCs alloyed with Group 10 metals (Pd or Pt). Notably, the Pd0 or Pt0 atom situated at the center of the distorted hexagonal antiprism Pd0/Pt0@Cu12 cage, coordinated with twelve Cu+ and two tBuC≡C- ligands. Moreover, ligand exchange strategies demonstrated the potential for Cl- and Br- to replace one or two alkynyl ligands positioned at the top or side of the NCs. The chirality exhibited by these racemic NCs is primarily attributed to the involvement of halogens and a chiral (Pd/Pt)@Cu18 skeleton. Furthermore, all the NCs exhibit near-infrared (NIR) luminescence, characterized by emission peaks at 705-755 nm, lifetimes ranging from 6.630 to 9.662 µs, and absolute photoluminescence quantum yields (PLQYs) of 1.75 %-2.52 % in their crystalline state. The experimental optical properties of these NCs are found to be in excellent agreement with the results of theoretical calculations. These alloy NCs not only offer valuable insights into the synthesis of Pd0/Pt0-Cu alloy NCs, but also bridge the gap in understanding the structure-luminescence relationships of Pd0/Pt0-Cu molecules.

Template-assisted synthesis of isomeric copper(i) clusters with tunable structures showing photophysical and electrochemical properties.

A comparative study of structure-property relationships in isomeric and isostructural atomically precise clusters is an ideal approach to unravel their fundamental properties. Herein, seven high-nuclearity copper(i) alkynyl clusters utilizing template-assisted strategies were synthesized. Spherical Cu36 and Cu56 clusters are formed with a [M@(V/PO4)6] (M: Cu2+, Na+, K+) skeleton motif, while peanut-shaped Cu56 clusters feature four separate PO4 templates. Experiments and theoretical calculations suggested that the photophysical properties of these clusters are dependent on both the inner templates and outer phosphonate ligands. Phenyl and 1-naphthyl phosphate-protected clusters exhibited enhanced emission features attributed to numerous well-arranged intermolecular C-H⋯π interactions between the ligands. Moreover, the electrocatalytic CO2 reduction properties suggested that internal PO4 templates and external naphthyl groups could promote an increase in C2 products (C2H4 and C2H5OH). Our research provides new insight into the design and synthesis of multifunctional copper(i) clusters, and highlights the significance of atomic-level comparative studies of structure-property relationships.

Stabilizing a non-IPR C2(13333)-C74 cage with Lu2C2/Lu2O: the importance of encaged non-metallic elements.

A difference in encaged non-metallic element (i.e., C2versus O) leads to a clear change of intramolecular interactions and shifts in redox potentials of Lu2C2@C2(13333)-C74 and Lu2O@C2(13333)-C74, as a result of their distinct molecular orbital energy levels. Different from these two endoherals whose HOMOs are located on the cage, experimentally absent Lu2@C2(13333)-C74 possesses a HOMO predominantly delocalized on the internal Lu-Lu bond, accompanied by a much smaller HOMO-LUMO gap, suggesting that the presence of a non-metallic unit broadens the electrochemical gaps and consequently improves the kinetic stability. These findings shed light on the role of non-metallic moieties in clusterfullerenes, providing valuable insights into the stability and properties of metallofullerenes.

Ag6 Cu8 (C=CAr)14 (DPPB)2 : A Rigid Ligand Co-Protected Bimetallic Silver(I)-Copper(I) Cluster with Room-Temperature Luminescence.

Metal clusters have become increasingly important in various applications, with ligands playing a crucial role in their construction. In this study, we synthesized a bimetallic cluster, Ag6 Cu8 (C=CAr)14 (DPPB)2 (Ag6 Cu8 ), using a rigid acetylene ligand, 3,5-bis(trifluoromethyl)phenylacetylide. Through single-crystal structure characterization, we discovered that the butterfly-shaped Ag2 Cu2 motifs were subject to distortion due to steric hindrance imposed by the rigid ligand. These motifs assembled together through shared vertices and edges. Mass spectrometry analysis revealed that the primary fragments detected during electrospray ionization (ESI) testing corresponded to the Ag2 Cu2 motifs. Furthermore, we conducted a comprehensive investigation of the cluster's solution properties employing 31 P NMR, UV-vis absorption, and photoluminescent measurements. In contrast to previously reported Ag/Cu bimetallic clusters protected by flexible ligands, Ag6 Cu8 protected by rigid ligands exhibited intriguing room temperature fluorescence properties alongside excellent thermal stability. DFT calculations on Ag6 Cu8 and Ag6 Cu8 with the rigid aromatic ring removed revealed that the presence of the rigid aromatic ring can lower the electronic energy levels of the cluster, and reduce the energy gap from 4.05 eV to 3.45 eV. Moreover, the rigid ligand further suppressed the non-radiative transition process, leading to room temperature fluorescence emission.

Anion-templated silver thiolated clusters affected by carboxylate ligands.

Under the guidance of anion templates V10O286- and SO42-, the novelty of cluster assembly can be increased by using different carboxylate ligands. Herein, the synthesis, crystal structure and electrochemical properties of three anion-templated silver thiolated clusters are reported, namely V10O28@Ag46(iPrS)28(CF3CO2)12(DMF)2 (1), V10O28@Ag46(iPrS)30(CF3CO2)8(PhCO2)2(DMF)4 (2), and [SO4@Ag20(iPrS)10(PTA)3(HPTA)2]n (3, H2PTA = phthalic acid). Single-crystal X-ray diffraction analysis showed that 1 and 2 are discrete clusters V10O28@Ag46. The addition of PhCO2H in the second step of 1 leads to obtaining 2 with different organic shells. If the addition of H2PTA is made, 3 with a three-dimensional (3D) structure containing the SO42- template can be obtained. Both V10O286- and SO42- templates were generated in situ under solvothermal conditions. This work is the first where heterogeneous silver clusters containing the V10O286- anion template protected by an isopropyl thiolate ligand and a Ag20 cluster with a 3D structure are obtained. The assembly process influenced by carboxylic acid deserves to be continuously explored in the future.

Unique Carbazole-Oxadiazole Derivatives as New Potential Antibiotics for Combating Gram-Positive and -Negative Bacteria.

Novel carbazole-oxadiazoles were developed as new potential antibacterial agents to combat dreadful resistance. Some target compounds displayed predominant inhibitory effects on the tested Gram-positive and -negative bacteria, and carbazole-oxadiazoles 5g, 5i-k, 16a-c, and tetrazole analogues 23b-c were found to be efficient in impeding the growth of MRSA and Pseudomonas aeruginosa ATCC 27853 (MICs = 0.25-4 µg/mL). Furthermore, compounds 5g and 23b-c not only possessed rapid bactericidal ability and low tendency to develop resistance but also exhibited low cytotoxic effects toward Hek 293T, HeLa, and red blood cells (RBCs), especially molecule 5g also showed low toxicity in vivo, which showed the therapeutic potential of these compounds. Further exploration indicated that compounds 5g, 5i, and 23b-c could disintegrate the integrity of bacterial cell membranes to leak the cytoplasmic contents, thus exerting excellent antibacterial effects. These facts mean that carbazole-based antibacterial agents might have bright prospects in confronting bacterial infections.

Erratum: CDC20 regulates cardiac hypertrophy via targeting LC3-dependent autophagy: Erratum.

[This corrects the article DOI: 10.7150/thno.27706.].

Copper(I) Alkynyl Clusters with Crystallization-Induced Emission Enhancement.

Four copper(I) alkynyl complexes incorporating phosphate ligands, namely, [Cu16(tBuC≡C)12(PhOPO3)2]n (1; PhOPO3 = phenyl phosphate), [Cu16(tBuC≡C)12(1-NaphOPO3)2]n (2; 1-NaphOPO3 = 1-naphthyl phosphate), [VO4@Cu25(tBuC≡C)19(1-NaphOPO3)](PF6)0.5(F)0.5 (3), and [PO4@Cu25(tBuC≡C)19(1-NaphOPO3)](PF6)0.5(F)0.5 (4), were solvothermally synthesized and well-characterized by IR spectroscopy, powder X-ray diffraction, and single-crystal X-ray diffraction. Single-crystal X-ray analysis revealed that the Cu16 cluster-based coordination chain polymers 1 and 2 are formed by assembly during crystallization, while 3 and 4 contain high-nuclearity copper(I) composite clusters enclosing orthovanadate and phosphate template ions, respectively, that are supported by ROPO32- ligands. Complexes 1-4 exhibit crystallization-induced emission enhancement. Their crystalline state shows strong luminescence, in striking contrast to the weak emission of the amorphous state and solution phase. A detailed investigation of the crystal structure suggests that well-arranged C-H···π and π···π interactions between the ligands are the major factors for this enhanced emission. Clusters 3 and 4 also exhibit photocurrent responses upon visible-light illumination.

A comparative study of [Ag11(iPrS)9(dppb)3]2+ and [Ag15S(sBuS)12(dppb)3]+: templating effect on structure and photoluminescence.

Atomically precise silver clusters with tunable photoluminescence (PL) properties have attracted extensive attention due to their great value for basic science and future applications. Here, we report that the addition of a sulfido template into a triangular thiolated silver cluster [Ag11(iPrS)9(dppb)3]·2CF3SO3·CH3OH (Ag11, dppb = 1,4-bis(diphenylphosphino)butane), which is emissive at 660 nm under ambient conditions, produced another silver cluster [S@Ag15(sBuS)12(dppb)3]·CF3SO3·H2O (Ag15) that displays 716 nm emission with a 56 nm redshift aided by the ligand sec-butyl mercaptan. The sulfido template, which affects the geometrical and electronic structures, results in a redshift of Ag11 room-temperature PL as a result of opening up the template-to-metal charge transfer (TMCT) and disturbing the electronic transition between the metal core and ligands at the periphery.

Novel carbazole-oxadiazoles as potential Staphylococcus aureus germicides.

Staphylococcus aureus resistance poses nonnegligible threats to the livestock industry. In light of this, carbazole-oxadiazoles were designed and synthesized for treating S. aureus infection. Bioassay discovered that 3,6-dibromocarbazole derivative 13a had effective inhibitory activities to several Gram-positive bacteria, in particular to S. aureus, S. aureus ATCC 29213, MRSA and S. aureus ATCC 25923 (MICs = 0.6-4.6 nmol/mL), which was more active than norfloxacin (MICs = 6-40 nmol/mL). Subsequent studies showed that 3,6-dibromocarbazole derivative 13a acted rapidly on S. aureus ATCC 29213 and possessed no obvious tendency to induce bacterial resistance. Further evaluations indicated that 3,6-dibromocarbazole derivative 13a showed strong abilities to disrupt bacterial biofilm and interfere with DNA, which might be the power sources of antibacterial performances. Moreover, 3,6-dibromocarbazole derivative 13a also exhibited slight cell lethality toward Hek 293 T and LO2 cells and low hemolytic toxicity to red blood cells. The above results implied that the active molecule 13a could be studied in the future development of agricultural available antibiotics.

Construction of Silver Clusters Capped by Zwitterionic Ethynide Ligands.

A zwitterionic ligand 3-(triethylammonio)propyne (TAP) has been employed to construct nine silver ethynide compounds for the first time. Single-crystal X-ray analyses reveal that compounds 1 and 2 are silver ethynide assemblies based on the Ag3 subunits and clusters 3-8 are small discrete clusters of Ag3, Ag6, Ag8, and Ag12, respectively, ligated by the bulky TAP ligand with different auxiliary ligands. In addition, upon acquiring the tripod-like tBuPO32-, a unprecedented 80 nuclei silver ethynide cluster was isolated and determined to be [(CF3CO2)5@Ag80(TAP)14(tBuPO3)16(CF3CO2)24]19+ by crystallography and thermogravimetric analysis. The C1 symmetry of Ag80 was deconstructed to be two [Ag40(TAP)7(tBuPO3)8(CF3CO2)12]12+ secondary building subunits arranged in a cross way, with five CF3CO2- trapped in the center. These results highlight that the elaborate selection of ethynide ligands is of great importance in the synthesis of novel silver ethynide clusters.

Controllable synthesis of porous tubular carbon by a Ag+-ligand-assisted Stöber-silica/carbon assembly process.

Herein, in this study, we utilized Ag+-ligand interactions for critically regulating the morphology of carbon by the Stöber-silica/carbon co-assembly method for the first time. Tetraethyl orthosilicate (TEOS) and resorcinol/formaldehyde (RF) assemble upon dictation by Ag+ and pyridyl-functionalized surfactants, producing porous carbon tubes (RF1) with a high surface area of 696 m2 g-1 and accessible mesopores ∼15 nm in size. Furthermore, when using tetrapropyl orthosilicate (TPOS) with a slower hydrolysis rate than that of TEOS, carbon tubes (RF2) with enhanced uniformity and a surface area as high as 2112 m2 g-1 are generated. Additionally, when using dopamine hydrochloride instead of RF as a carbon precursor, tubular polydopamine (TDA) with lengths of tens of microns is fabricated, which exhibits excellent catalytic activity toward oxygen reduction reactions in alkaline solutions due to its unique structural feature, a high surface area of 1350 m2 g-1, metallic silver remains of 8.3 wt%, and a rich nitrogen content of 3.6 wt%. This work sheds light on the engineering of a micellar soft template and synthesizing novel nanostructures by the extension of the Stöber method.

Nestlike Silver(I) Thiolate Clusters with Tunable Emission Color Templated by Heteroanions.

Four silver thiolate clusters, [H3 O][(Ag3 S3 )(BF4 )@Ag27 (tBuS)18 (hfac)6 H2 O]⋅H2 O (1; hfac = hexafluoroacetylacetone), [(Ag3 S3 )(CF3 CO2 )@Ag30 (tBuS)16 (CF3 CO2 )9 (CH3 CN)4 ]⋅CF3 CO2 ⋅4 CH3 CN (2), [(Ag3 S3 )(MoO4 )@Ag30 (tBuS)16 (CF3 CO2 )9 (CH3 CN)4 ]⋅2 CH3 CN (3), and [(Ag3 S3 )(CrO4 )@Ag30 (tBuS)16 (CF3 CO2 )9 (CH3 CN)4 ]⋅4 CH3 CN (4), were isolated. They have similar nestlike structures assembled by an [Ag3 S3 ]3- template together with one of the BF4 - , CF3 CO2 - , MoO4 2- , or CrO4 2- anions. Interestingly, the solid-state emissions of 2-4 are dependent on the templating anions and are tunable from green to orange and then to red by changing the template from CF3 CO2 - to MoO4 2- and to CrO4 2- , and this may be correlated to the charge transfer between these templates to metal atoms. This work helps to understand the templating role of heteroanions and the relationship between structure and properties.

tert-Butyl thiol and pyridine ligand co-protected 50-nuclei clusters: the effect of pyridines on Ag-SR bonds.

Constructing silver(i)-thiolate clusters from simple building blocks usually involves elusive self-assembly processes and remains a long-standing challenge. In this work, we report 6 silver(i)-thiolate clusters protected by pyridines, namely, [Ag3(tBuS)2(Py)(NO3)]n (Py = pyridine) (1), [Ag10(tBuS)6(Py)6(CF3CO2)4]·3Py (2), [Ag12(iPrS)6(Py)8(NO3)6]·2H2O (3), Ag12(iPrS)6(Py)8(CF3CO2)6 (4), Ag12(iPrS)6(4-ap)6(NO3)6 (4-ap = 4-aminopyridine) (5), and [Ag50S13(tBuS)20(Py)12]·4BF4·4Py·4CH3OH·2H2O (6). Single-crystal X-ray crystallography analysis reveals that six clusters are constructed by four types of structural blocks, including the PyAg(tBuS)2 monomer, Py2Ag2(tBuS)2 dimer, Py3Ag3(tBuS)3 trimer and (4-ap)6Ag6(iPrS)6 hexamer. Notably, cluster 6 consists of a rhombic dodecahedron S@Ag14 kernel with 12 interstitial S2- atoms encapsulated by 8 µ4-tBuS- ligands, as well as six unique butterfly-like (Py)2Ag6(tBuS)2 staple motifs composed of a Py2Ag2(tBuS)2 dimer and four silver ions. Moreover, it is found that pyridine ligands have important influence on the construction of silver thiolate clusters and their Ag-SR bond lengths.

IL-18/IL-18R1 promotes circulating fibrocyte differentiation in the aging population.

BACKGROUND: Fibrosis in multiple organs increases with age. Circulating fibrocytes are bone-marrow-derived mesenchymal progenitors that contribute to heart, lung, and kidney fibrosis under the diseased conditions. Whether circulating fibrocytes contribute to aging-related fibrosis is very limited. METHODS AND RESULTS: We measured the proportion and differentiation of circulating fibrocytes (CD45+/CD34+/collagen I+) from elders (n = 12) and adults (n = 12) using flow cytometry. Differentiated fibrocytes in the culture dishes were isolated and microarray was performed. The percentage of circulating fibrocytes in elders (1.95 ± 0.43%) was comparable to that in the adults (1.71 ± 0.38%). Cultured fibrocytes displayed enhanced potential of differentiation in the elder group (67.91 ± 5.88%) vs the adult group (44.03 ± 7.98%). In addition, expression of fibroblast activation markers and cell migratory ability were also increased in differentiated fibrocytes from elders. Microarray analysis revealed that differentiated fibrocytes from elders expressed high level of interleukin-18 (IL-18) receptor 1 (IL-18R1). Furthermore, we found IL-18 was elevated in the plasma of elders and IL-18/IL-18R1 was shown to promote fibrocyte differentiation. CONCLUSION: Circulating fibrocytes from elders had an enhanced capacity to differentiate into myofibroblasts, and might contribute to age-dependent fibrosis. Age-dependent increment of differentiation at least in part arose from their enhanced expression of IL-18R1. Inhibiting fibrocyte differentiation might be useful as an adjuvant treatment to delay the fibrosis process in aging population.

Oxometalate and phosphine ligand co-protected silver nanoclusters: Ag28(dppb)6(MO4)4 and Ag32(dppb)12(MO4)4(NO3)4.

Thiols, alkynyls and phosphines are the most widely used organic ligands to attain atomically precise metal nanoclusters, while oxometalates as inorganic ligands have almost been neglected in this field. Here, we used oxometalates (e.g., MoO42- and WO42-) as protecting ligands along with phosphines, such as 1,4-bis(diphenylphosphino)butane (dppb), to design and synthesize a new class of silver nanoclusters including Ag28(dppb)6(MoO4)4, Ag28(dppb)6(WO4)4 and Ag32(dppb)12(MoO4)4(NO3)4. Each cluster consists of a two-shell Ag4@Ag24 core protected by 4 oxometalates. These clusters exhibit similar optical absorption and photoluminescence properties that are not dependent on surface ligands. Furthermore, the electronic structure analysis shows that the clusters are 20-electron "superatoms". This work demonstrates that oxometalates can play a key role in the formation of silver nanoclusters, and the effect of oxometalates should be considered in the design and synthesis of metal nanoclusters.

A disulfur ligand stabilization approach to construct a silver(i)-cluster-based porous framework as a sensitive SERS substrate.

An atomically-precise silver(i)-cluster-based three-dimensional (3D) framework (UJN-1) stabilized by a ditiocarb (diethyldithiocarbamate) ligand has been unveiled for the first time by self-assembly. UJN-1 is composed of both Ag9 clusters and Ag5 subunits, of which the Ag9 clusters are bonded with Ag5 subunits by sharing the ditiocarb ligand to form a microporous 3,4-connected topological framework. The chemically reduced nano-sized derivative of UJN-1 exhibits highly sensitive surface enhanced Raman scattering (SERS) towards 4-mercaptobenzoic acid (4-MBA) signal molecules, which is ascribed to the porosity as well as the distribution of abundant crystalline Ag0 active sites. This work sheds light on a new bottom-up approach to construct SERS-active silver(i)-cluster-based 3D materials by disulfur ligand stabilization.

A new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antibacterial agents: Design, synthesis and evaluation acting on microbes, DNA, HSA and topoisomerase IV.

This work did a new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antimicrobial agents. A class of novel hybrids of quinolone, aminothiazole, piperazine and oxime fragments were designed for the first time, conveniently synthesized as well as characterized by 1H NMR, 13C NMR and HRMS spectra. Biological activity showed that some of the synthesized compounds exhibited good antimicrobial activities in comparison with the reference drugs. Especially, O-methyl oxime derivative 10b displayed excellent inhibitory efficacy against MRSA and S. aureus 25923 with MIC values of 0.009 and 0.017 mM, respectively. Further studies indicated that the highly active compound 10b showed low toxicity toward BEAS-2B and A549 cell lines and no obvious propensity to trigger the development of bacterial resistance. Quantum chemical studies have also been conducted and rationally explained the structural features essential for activity. The preliminarily mechanism exploration revealed that compound 10b could not only exert efficient membrane permeability by interfering with the integrity of cells, bind with topoisomerase IV-DNA complex through hydrogen bonds and π-π stacking, but also form a steady biosupramolecular complex by intercalating into DNA to exert the efficient antibacterial activity. The supramolecular interaction between compound 10b and human serum albumin (HSA) was a static quenching, and the binding process was spontaneous, where hydrogen bonds and van der Waals force played vital roles in the supramolecular transportation of the active compound 10b by HSA.

Hybrid Rare-Earth(III)/Bismuth(III) Clusters Assembled with Phosphonates.

tert-Butylphosphonic acid and rare-earth precursors are employed to construct four trinuclear rare-earth phosphonate clusters, RE3( tBuPO3)2(hfac)5(CH3OH)8]·2CH3OH (RE = Eu, Y, Pr, and Sm; hfac = hexafluoroacetylacetonate), which are composed of three RE3+ ions alternately bridged by two phosphonates. With the introduction of bismuth oxido diketonate, [Bi9O7(hfac)13], three different types of rare-earth/bismuth phosphonate clusters, Bi12RE2 (RE = Pr and Sm), Bi6Eu7, and Bi6Y9, are successfully obtained via variation of the reaction conditions, and they are the first reported examples of bismuth-oxo clusters encapsulated by cyclic rare-earth-oxo or rare-earth/bismuth-oxo phosphonate clusters, respectively. These clusters show obvious absorption in the UV region, and the Eu-containing clusters exhibit bright-red fluorescence.