Assembly of Copper Alkynyl Clusters into Dimensionally Diverse Coordinated Polymers Mediated by Pyridine Ligands.

Surface ligands play crucial roles in modifying the properties of metal nanoclusters and stabilizing atomically precise structures, and also serve as vital linkers for constructing cluster-based coordination polymers. In this study, we present the results of the solvothermal synthesis of eight novel copper alkynyl clusters incorporating pyridine ligands using a one-pot method. The resulting compounds underwent characterization through elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD). Our observations revealed that distinct pyridine ligands with varying lengths and coordination sites exert significant influence on the structure and dimensionality of the clusters. The structural diversity of these clusters led to the formation of one-dimensional (1D), two-dimensional (2D), or dimer arrangements linked by seven pyridine bridging ligands. Remarkably, these complexes exhibited unique UV-vis absorption and photoluminescence properties, which were influenced by the specific bridging ligand and structural framework. Furthermore, density functional theory (DFT) calculations demonstrated the capability of the conjugated system in the pyridine ligand to impact the band gap of clusters. This study not only unveils the inherent structural diversity in coordination polymers based on copper alkynyl clusters but also offers valuable insights into harnessing ligand engineering for structural and property modulation.

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.

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.

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.

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.

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.

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.

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.

Cardiac Ablation of SOCS3 Aggravates DOCA-Salt-Induced Hypertrophic Remodeling by Activation of Gp130-Dependent Signaling in Mice.

BACKGROUND/AIMS: Cardiac remodeling is a critical pathogenetic process leading to heart failure. Suppressor of cytokine signaling-3 (SOCS3) is demonstrated as a key negative regulator of the gp130 receptor to inhibit cardiac hypertrophy. However, the role of SOCS3 in deoxycorticosterone-acetate (DOCA)-salt-induced cardiac remodeling remains unclear. METHODS: Cardiac-specific SOCS3 knockout (SOCS3cKO) and wild-type (WT) C57BL/6J mice were subjected to uninephrectomy and DOCA-salt for 3 weeks. The effect of SOCS3 on cardiac remodeling and inflammation was evaluated by histological analysis. Gene and protein levels were measured by real-time PCR and immunoblotting analysis. RESULTS: After DOCA-salt treatment, the expression of SOCS3, activation of gp130/JAK/STAT3, cardiac dysfunction and fibrosis in DOCA-salt mice were significantly elevated, which were markedly attenuated by eplerenone, a specific mineralocorticoid receptor (MR) blocker. Moreover, DOCA-salt-induced cardiac dysfunction, hypertrophy, fibrosis and inflammation were aggravated in SOCS3cKO mice, but were significantly reduced in AAV9-SOCS3-injected mice. These effects were mostly associated with activation of gp130/STAT3/AKT/ERK1/2, TGF-ß/Smad2/3 and NF-κB signaling pathways. CONCLUSIONS: Our data demonstrate that loss of SOCS3 in cardiomyocytes promotes DOCA-salt-induced cardiac remodeling and inflammation, and it may be a novel potential therapeutic target for hypertensive heart disease.

High-Nuclearity Heterometallic tert-Butylethynide Clusters Assembled with tert-Butylphosphonate.

tert-Butylphosphonic acid and lanthanide precursors were employed to construct two high-nuclearity hybrid silver(I)-ytterbium(III) phosphonate clusters: compound 1 consists of a Ag16 ethynide cluster fused with a trinuclear hydroxoytterbium phosphonate cluster, whereas compound 2 is composed of two Ag16 ethynide clusters bridged by a hexanuclear oxo/hydroxoytterbium phosphonate cluster. Using transition-metal-substituted lacunary polyoxotungstates in place of the lanthanide reactant, new phosphonate-functionalized silver(I)-copper(II) ethynide clusters [Ag34 Cu6 (3) and Ag37 Cu6 (4)] and silver(I) ethynide clusters [Ag51 (5) and Ag72 (6)] were obtained. The structures of complexes 3-6 feature core-shell arrangements, in which silver(I)-copper(II) or silver(I) ethynide cluster shells stabilized by peripheral phosphonate ligands enclose different kinds of tungstate core templates.

Isolation and Crystallographic Characterization of Lu3 N@C2n (2n=80-88): Cage Selection by Cluster Size.

The small Sc3 N cluster has only been found in such small cages as C2n (2n=68, 78, 80, 82), whereas the large M3 N (M=Y, Gd, Tb, Tm) clusters choose those larger cages C2n (2n=82-88). Herein, concrete experimental evidence is presented to establish the size effect of the internal metallic cluster on selecting the outer cage of endohedral metallofullerenes (EMFs) by using a medium-sized metal, lutetium, which possesses an ionic radius between Sc and Gd. A series of lutetium-containing EMFs have been obtained and their structures are unambiguously determined as Lu3 N@Ih (7)-C80 , Lu3 N@D5h (6)-C80 , Lu3 N@C2v (9)-C82 , Lu3 N@Cs (51365)-C84 , Lu3 N@D3 (17)-C86 , and Lu3 N@D2 (35)-C88 by single-crystal X-ray diffraction crystallography. It was confirmed that the encaged Lu3 N cluster always adopts a planar geometry in Lu3 N@C80-88 isomers to ensure substantial metal-cage/metal-nitrogen interactions. As a result, the Lu3 N cluster selects the C2v (9)-C82 cage, which also encapsulates Sc3 N, instead of the Cs (39663)-C82 cage which is more suitable for M3 N (M=Y, Gd, Tb, Tm). However, different from Sc3 N, Lu3 N can also template the C84-88 cages which are absent for Sc3 N-containing EMFs, confirming clearly the size effect of the internal cluster on selecting the outer cage.

Structure-Directing Role of Phosphonate in the Synthesis of High-Nuclearity Silver(I) Sulfide-Ethynide-Thiolate Clusters.

Phosphonate ligands as structure-directing components have been employed to construct four new high-nuclearity silver(I) sulfide-ethynide-thiolate clusters, in which silver(I) aggregates tBuC≡C⊃Ag3, tBuC≡C⊃Ag4, and 2tBuC≡C⊃Ag7 are bridged by tBuS- ligands to engender respective silver(I) ethynide-thiolate clusters functioning as integral shell components, which are supported by phosphonate ligands. In each silver(I) sulfide-ethynide-thiolate cluster, a different encapsulated silver sulfide cluster serves as a core template.

A three-dimensional complex with a one-dimensional cobalt-hydroxyl chain based on planar nonanuclear clusters showing spin-canted antiferromagnetism.

A new three-dimensional magnetic network, [Co9(OH)6(C42H24O18P3N3)2(H2O)8] (1), has been successfully prepared by utilizing the flexible hexacarboxylate ligand derived from cyclotriphosphazene, which had been characterized by single-crystal X-ray diffraction and magnetic measurement. This compound consists of one-dimensional (1D) cobalt-hydroxyl chains based on planar nonanuclear clusters, which are located in the b-c plane to form the nearly two-dimensional cobalt layer. Magnetic measurements reveal that 1 shows spin-canted antiferromagnetism with spin-glass behavior. These results suggest that reasonable design and choice of large carboxylate ligand based on a specific scaffold could be effective for the construction of magnetic materials based on a novel 1D magnetic chain.

High-Nuclearity Silver Thiolate Clusters Constructed with Phosphonates.

The n-butylphosphonate ligand has been employed to construct three new silver(I) thiolate compounds. Single-crystal X-ray analysis revealed that complexes 1 and 2 are Ag48 and Ag51 coordination chain polymers, while 3 contains a discrete Ag48 cluster, in which three different kinds of silver(I) thiolate cluster shells enclose three different phosphonate-functionalized silver(I) cluster cores, respectively. The structures of clusters in 1-3 feature three three-shell arrangements, S@Ag12 @(nBuPO3 )9 @Ag36 S23 , S@Ag11 @(nBuPO3 )7 (MoO4 )2 @Ag40 S27 and MoO4 @Ag12 @(nBuPO3 )8 S6 @Ag36 S24 , respectively.

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.

Silver(I) ethynide coordination networks and clusters assembled with tert-butylphosphonic acid.

Variation of the reaction conditions with AgC≡CR (R = Ph, C(6)H(4)OCH(3)-4, (t)Bu), (t)BuPO(3)H(2), and AgX (X = NO(3), BF(4)) as starting materials afforded four new silver(I) ethynide complexes incorporating the tert-butylphosphonate ligand, namely, 3AgC≡CPh·Ag(2)(t)BuPO(3)·Ag(t)BuPO(3)H·2AgNO(3) (1), 2AgC≡CC(6)H(4)OCH(3)-4·Ag(2)(t)BuPO(3)·2AgNO(3) (2), [{Ag(5)(NO(3)@Ag(18))Ag(5)}((t)BuC≡C)(16)((t)BuPO(3))(4)(H(2)O)(3)][{Ag(5)(NO(3)@Ag(18))Ag(5)} ((t)BuC≡C)(16)((t)BuPO(3))(4)(H(2)O)(4)]·3SiF(6)·4.5H(2)O·3.5MeOH (3), and [{Ag(8)(Cl@Ag(14))}((t)BuC≡C)(14)((t)BuPO(3))(2)F(2)(H(2)O)(2)]BF(4)·3.5H(2)O (4). Single-crystal X-ray analysis revealed that complexes 1 and 2 display different layer-type coordination networks, while 3 and 4 contain high-nuclearity silver(I) composite clusters enclosing nitrate and chloride template ions, respectively, that are supported by (t)BuPO(3)(2-) ligands.

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.

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.