An Unusual Crystalline Porous Framework Constructed from Multitypes of Cages with Proton Conduction Property and Heterogeneous Catalytic Activity for Pyrazole Synthesis.

An unusual crystalline porous framework constructed from four types of cages, including all-inorganic Keggin-type polyoxometalate (POM) cages [H3W12O40]5-, organic hexamethylenetetramine (Hmt) cages, nanosized silver-Hmt coordination cages, and giant POM-silver-Hmt cages, was hydrothermally synthesized and structurally characterized. The framework features a highly symmetrical structure with one-dimensional nanoscale channels and holds good thermal/solvent stability, which endow it with proton conduction properties and heterogeneous catalytic activity for pyrazole. This paper not only contributes to broadening the structural diversity of cage-based crystalline porous framework materials but also sheds new light on the design of new functional framework materials.

Enhancement of Magneto-Chiral Dichroism Intensity by Chemical Design: The Key Role of Magnetic-Dipole Allowed Transitions.

Here we report on the strong magneto-chiral dichroism (MChD) detected through visible and near-infrared light absorption up to 5.0 T on {Er5Ni6} metal clusters obtained by reaction of enantiopure chiral ligands and NiII and ErIII precursors. Single-crystal diffraction analysis reveals that these compounds are 3d-4f heterometallic clusters, showing helical chirality. MChD spectroscopy reveals a high gMChD dissymmetry factor of ca. 0.24 T-1 (T = 4.0 K, B = 1.0 T) for the 4I13/2 ← 4I15/2 magnetic-dipole allowed electronic transition of the ErIII centers. This record value is 1 or 2 orders of magnitude higher than that of the d-d electronic transitions of the NiII ions and the others f-f electric-dipole induced transitions of the ErIII centers. These findings clearly show the key role that magnetic-dipole allowed transitions have in the rational design of chiral lanthanide systems showing strong MChD.

An organophosphate 3d-4f heterometallic polyoxoniobate nanowire.

Four different structural compositions of organophosphate, 3d transition metal, 4f lanthanide and polyoxoniobate (PONb) are unified in a system for the first time to form a new type of organophosphate 3d-4f heterometallic inorganic-organic hybrid PONb nanowire. Interesting magnetic anisotropy and slow magnetic relaxation are found in the PONb nanowire.

Magneto-optical Properties of Chiral Co2Ln and Co3Ln2 (Ln = Dy and Er) Clusters.

A series of chiral heterometallic Ln-Co clusters, denoted as Co2Ln and Co3Ln2 (Ln = Dy and Er), were synthesized by reacting the chiral chelating ligand (R/S)-2-(1-hydroxyethyl)pyridine (Hmpm), CoAc2·4H2O, and Ln(NO3)3·6H2O. Co2Ln and Co3Ln2 exhibit perfect mirror images in circular dichroism within the 320-700 nm range. Notably, the Co2Er and Co3Er2 clusters display pronounced magnetic circular dichroism (MCD) responses of the hypersensitive f-f transitions 4I15/2-4G11/2 at 375 nm and 4I15/2-2H11/2 at 520 nm of ErIII ions. This study highlights the strong magneto-optical activity associated with hypersensitive f-f transitions in chiral 3d-4f magnetic clusters.

Tuning Electrocatalytic Water Oxidation Activity: Insights from the Active-Site Distance in LnCu6 Clusters.

Atomically precise metal clusters serve as a unique model for unraveling the intricate mechanism of the catalytic reaction and exploring the complex relationship between structure and activity. Herein, three series of water-soluble heterometallic clusters LnCu6, abbreviated as LnCu6-AC (Ln = La, Nd, Gd, Er, Yb; HAC = acetic acid), LnCu6-IM (Ln = La and Nd; IM = Imidazole), and LnCu6-IDA (Ln = Nd; H2IDA = Iminodiacetic acid) are presented, each featuring a uniform metallic core stabilized by distinct protected ligands. Crystal structure analysis reveals a triangular prism topology formed by six Cu2+ ions around one Ln3+ ion in LnCu6, with variations in Cu···Cu distances attributed to different ligands. Electrocatalytic oxygen evolution reaction (OER) shows that these different LnCu6 clusters exhibit different OER activities with remarkable turnover frequency of 135 s-1 for NdCu6-AC, 79 s-1 for NdCu6-IM and 32 s-1 for NdCu6-IDA. Structural analysis and Density Functional Theory (DFT) calculations underscore the correlation between shorter Cu···Cu distances and improves OER catalytic activity, emphasizing the pivotal role of active-site distance in regulating electrocatalytic OER activities. These results provide valuable insights into the OER mechanism and contribute to the design of efficient homogeneous OER electrocatalysts.

Soluble Gd6Cu24 clusters: effective molecular electrocatalysts for water oxidation.

The water oxidation half reaction in water splitting for hydrogen production is extremely rate-limiting. This study reports the synthesis of two heterometallic clusters (Gd6Cu24-IM and Gd6Cu24-AC) for application as efficient water oxidation catalysts. Interestingly, the maximum turnover frequency of Gd6Cu24-IM in an NaAc solution of a weak acid (pH 6) was 319 s-1. The trimetallic catalytic site, H2O-GdIIICuII2-H2O, underwent two consecutive two-electron two-proton coupled transfer processes to form high-valent GdIII-O-O-CuIII2 intermediates. Furthermore, the O-O bond was formed via intramolecular interactions between the CuIII and GdIII centers. The results of this study revealed that synergistic catalytic water oxidation between polymetallic sites can be an effective strategy for regulating O-O bond formation.

From Helices to Crystals: Multiscale Representation of Chirality in Double-Helix Structures.

Single crystals with chiral shapes aroused the interest of chemists due to their fascinating polarization rotation properties. Although the formation of large-scale spiral structures is considered to be a potential factor in chiral crystals, the precise mechanism behind their formation remains elusive. Herein, we present a rare phenomenon involving the multitransfer and expression of chirality at micro-, meso-, and macroscopic levels, starting from chiral carbon atoms and extending to the double-helical secondary structure, ultimately resulting in the chiral geometry of crystals. The assembly of the chiral double helices is facilitated by the dual characteristics of amide groups derived from amino acids, which serve as both hydrogen bond donors and receptors, similar to the assembly pattern observed in DNA. Crystal face analysis and theoretical morphology reveal two critical factors for the mechanism of the chiral crystal: inherent intrinsically symmetrical distribution of crystal faces and their acquired growth. Importantly, the magnetic circular dichroism (MCD) study reveals the strong magneto-optical response of the hypersensitive f-f transition in the UV-vis-NIR region, which is much stronger than previously observed signals. Remarkably, an external magnetic field can reverse the CD signal. This research highlights the potential of lanthanide-based chiral helical structures as promising magneto-optical materials.

Exploration and Insights on Topology Adjustment of Giant Heterometallic Cages Featuring Inorganic Skeletons Assisted by Machine Learning.

Inorganic molecular cages are emerging multifunctional molecular-based platforms with the unique merits of rigid skeletons and inherited properties from constituent metal ions. However, the sensitive coordination bonds and vast synthetic space have limited their systematic exploration. Herein, two giant cage-like clusters featuring the organic ligand-directed inorganic skeletons of Ni4[La74Ni104(IDA)96(OH)184(C2O4)12(H2O)76]·(NO3)38·(H2O)120 (La74Ni104, 5 × 5 × 3 - C2O4) and [La84Ni132(IDA)108(OH)168(C2O4)24(NO3)12(H2O)116]·(NO3)72·(H2O)296 (La84Ni132, 5 × 5 × 5 - C2O4) were discovered by a high-throughput synthetic search. With the assistance of machine learning analysis of the experimental data, phase diagrams of the two clusters in a four-parameter synthetic space were depicted. The effect of alkali, oxalate, and other parameters on the formation of clusters and the mechanism regulating the size of two n × m × l clusters were elucidated. This work uses high-throughput synthesis and machine learning methods to improve the efficiency of 3d-4f cluster discovery and finds the highest-nuclearity 3d-4f cluster to date by regulating the size of the n × m × l inorganic cages through oxalate ions, which pushes the synthetic methodology study on elusive inorganic giant cages in a significantly systematic way.

Uranyl Polyoxotungstate Cluster for Visible-Light-Driven Heterogeneous C-H Selective Fluorination.

The selective fluorination of C-H bonds at room temperature using heterogeneous visible-light catalysts is both interesting and challenging. Herein, we present the heterogeneous sandwich-type structure uranyl-polyoxotungstate cluster Na17{Na@[(SbW9O33)2(UO2)6(PO3OH)6]}·46H2O (denoted as U6P6) to regulate the selective fluorination of the C-H bond under visible light and room temperature. This is the first report in which uranyl participates in the fluorination reaction in the form of an insoluble substance. U6P6 is capable of the effective selective fluorination of cycloalkanes and the recyclability of the photocatalyst due to the synergistic effect of multiple uranyl (UO2)2+ and the insolubility of organic reagents of polyoxotungstate. In situ electron paramagnetic resonance spectroscopy captured the generation of cycloalkane radicals during the photoreaction, confirming the mechanism of direct hydrogen atom transfer.

Conductive Lanthanide Metal-Organic Frameworks with Exceptionally High Stability.

Electrically conductive metal-organic frameworks (MOFs) have been extensively studied for their potential uses in energy-related technologies and sensors. However, achieving that goal requires MOFs to be highly stable and maintain their conductivity under practical operating conditions with varying solution environments and temperatures. Herein, we have designed and synthesized a new series of {[Ln4(µ4-O)(µ3-OH)3(INA)3(GA)3](CF3SO3)(H2O)6}n (denoted as Ln4-MOFs, Ln = Gd, Tm, and Lu, INA = isonicotinic acid, GA = glycolic acid) single crystals, where electrons are found to transport along the π-π stacked aromatic carbon rings in the crystals. The Ln4-MOFs show remarkable stability, with minimal changes in conductivity under varying solution pH (1-12), temperature (373 K), and electric field as high as 800 000 V/m. This stability is achieved through the formation of strong coordination bonds between high-valent Ln(III) ions and rigid carboxylic linkers as well as hydrogen bonds that enhance the robustness of the electron transport path. The demonstrated lanthanide MOFs pave the way for the design of stable and conductive MOFs.

Exploring Diversity through Dimerization in Natural Products by a Rational Tandem Mass-Based Molecular Network Strategy.

The step- and atom-efficient dimerization strategy is frequently used in nature to build structural complexity and diversity. We propose the rationale and structural features of the versatile monomers that are responsible for "diversity through dimerization". Using 5-FAM-maleimide combined with a UHPLC-MS/MS-FBMN workflow, we successfully identified a diverse set of dimeric natural products from fungus Panus rudis F01315, in which all four complex 4'5-ring scaffolds are derived from one monomeric epoxyquinol and endowed with functional diversity.

Dual-Responsive Triple-Synergistic Fe-MOF for Tumor Theranostics.

The intelligent responsive drug delivery system has great application potential in cancer precision therapy. Although many antitumor methods have been developed based on drug delivery systems, most of them yet suffer from poor antitumor efficiency. In this project, a near-infrared and pH dual-response multimodal collaborative platform for diagnosis and treatment (PCN-DOX@PDA) was constructed. We used PCN-600 as a vehicle loaded with antineoplastic drugs and polydopamine (PDA). Under 633 nm laser irradiation, the ligand tetrakis(4-carboxyphenyl)porphyrin (TCPP) in PCN-600 can generate singlet oxygen (1O2) and kill tumor cells. PDA is used as photothermal agent of PTT. PCN-DOX@PDA achieves the intelligent release of antitumor drugs by responding to the weak acidity of the tumor microenvironment and thermal stimulation generated by NIR irradiation. In addition, since the central ion of PCN is Fe3+, PCN-DOX@PDA realizes the diagnosis and treatment of tumors through magnetic resonance imaging-mediated tumor chemotherapy and photothermal and photodynamic synergistic therapy. This triple synergistic strategy showed excellent biocompatibility and antitumor ability in in vivo experiments on a 4T1 tumor-bearing mouse model, indicating that PCN-DOX@PDA has a good development prospect in the field of precision cancer therapy and diversified biomedical applications.

Functionalization of Keggin Fe13-Oxo Clusters.

Two Keggin Fe13-oxo clusters, [Pr12Fe33(NO3)6(L-van)4(D-van)5(TEOA)12(µ3-OH)12(µ4-OH)12(µ4-O)28(H2O)4]·(ClO4)3·(NO3)·10H2O (1) and [Dy12Fe33(NO3)2(L-van)3(D-van)3(TEOA)12(µ3-OH)18(µ4-OH)6(µ4-O)28(H2O)9]·(ClO4)5·(NO3)6·15H2O (2), where L-van = l-valine, D-van = d-valine, and TEOA = triethanolamine, were prepared by using Ln3+ as a stabilizer. Cluster 1 crystallizes in a chiral space group of C2, while cluster 2 crystallizes in a centrosymmetric space group of Pnma. Dynamic magnetic measurements of 2 under a zero direct-current field reveal that 2 exhibits single-molecule-magnet characteristics with an energy barrier of 18.79 K. Significantly, the formation of the chiral cluster 1 is closely related to the larger radius of the Pr3+ ion.

Circularly polarized luminescence and performance modulation of chiral europium-titanium (Eu2Ti4)-oxo clusters.

The designed synthesis of chiral luminescent molecules with excellent circularly polarized luminescence (CPL) performance and high quantum yield (QY) levels has attracted great interest but remains very challenging. Herein, we report three pairs of chiral europium-titanium-oxo clusters featuring both modest CPL characteristics and high QY levels (up to 79%), which can be regulated by switching between different ligand substituents.

Aminopolyol-Dependent Assembly of Heterometallic Lanthanide-Iron-Oxo Clusters.

Lanthanide-iron clusters usually display interesting structures and outstanding magnetic properties. However, due to the high reactivity (acidity) of the Fe3+-H2O bond and the inability to form a terminal oxo ligand, the preparation of high-nuclearity Ln-Fe clusters is a great challenge. Herein, a series of lanthanide-iron-oxo clusters with the formulas [Y6Fe(HL)10(NO3)2(EG)2(µ3-OH)8(H2O)4]·ClO4·N-H2BDEA·2H2O (Y6Fe, 1, H2L = 3-hydroxypivalic acid, EG = ethylene glycol, N-H2BDEA = 2,2'-(butylimino)diethanol), [Ln8Fe3(H2TEOA)2(HTEOA)2(HL)10(µ3-OH)9(µ2-OH)(µ4-O)2(H2O)4]·(NO3)3·xH2O (Ln = Y, x = 13 for 2, Y8Fe3; Ln = Dy, x = 10 for 3, Dy8Fe3; H3TEOA = triethanolamine), and [Ln12Fe14(HL)16(µ3-OH)20(µ2-OH)12(µ4-O)12(H2O)12]·(NO3)6·xH2O (Ln = Y, x = 40 for 4, Y12Fe14; Ln = Dy, x = 30 for 5, Dy12Fe14) were obtained by adjusting the pH with different aminopolyols as organic alkalis. Structural analysis showed that a cubane-like unit was the main structural unit in compounds 1-5. Compound 1 was formed by two {Y3Fe(µ3-OH)4} units with the common vertices, and compounds 2 and 3 were formed by two {Y3Fe(µ3-OH)3(µ4-O)} units with the common vertices bridging a quadrilateral unit {Ln2Fe2(µ3-OH)3(µ2-OH)}. The basic structural units of cubane-like {Ln2Fe2(µ3-OH)(µ4-O)3}, triangular {LnFe2(µ3-OH)2(µ4-O)}, and neutral iron-hydroxyl {Fe(µ3-OH)(µ2-OH)2} were found in compounds 4 and 5. The universality of building blocks for the assembly has been demonstrated in high-nuclearity lanthanide-iron-oxo clusters. Meanwhile, the structural regulation of the lanthanide-iron-oxo clusters 1-5 was realized by adjusting the pH with different organic alkalis, which provided the reference for the effective synthesis of high-nuclearity lanthanide-iron-oxo clusters. Magnetic studies showed that 3 and 5 displayed a slow magnetic relaxation behavior.

Interplay between anisotropy and magnetic exchange to modulate the magnetic relaxation behaviours of phenoxo bridged Dy2 dimers with axial ß-diketonate co-ligands.

A series of Schiff base LH ((E)-2-((pyridin-2-ylmethylene)amino)phenol) supported phenoxo bridged symmetric [Dy2(L)2(hfac)4] (1), [Dy2(L)2(tfac)4] (2) and asymmetric [Dy2(L)2(thd)3(NO3)]·1.5H2O (3) binuclear complexes were isolated using differently substituted ß-diketonate co-ligands (Hhfac = hexafluoroacetylacetonate, Htfac = trifluoroacetylacetonate, and Hthd = 2,2,6,6-tetramethyl-3,5-heptanedione). In all the three complexes 1-3, the two LH ligands provide phenoxo bridging and N-donor atoms. The {Dy2(µ2-O)2} magnetic core structures with LH ligands are found to be the same in 1-3 while the dissimilar functionalities of the axially coordinated different ß-diketonate co-ligands play a crucial role in modulating the magnetic anisotropy of individual DyIII sites and magnetic exchange between them. The experimental static magnetic behaviour suggests the presence of intramolecular antiferromagnetic interactions in all the three complexes 1-3. The strength of the magnetic exchange coupling decreases with increasing magnetic anisotropy of individual DyIII ions from complex 1 to complex 3 and simultaneously their zero-field slow magnetic relaxation behaviors were found to increase with effective energy barriers (ΔE/kB) of 9.04 K, 24.06 K and 25.65 K, respectively. Furthermore, the DFT and ab initio theoretical calculations performed on the X-ray structures of complexes 1-3 support our experimental findings.

From a Metal-Organic Square to a Robust and Regenerable Supramolecular Self-assembly for Methane Purification.

Porous supramolecular assemblies constructed by noncovalent interactions are promising for adsorptive purification of methane because of their easy regeneration. However, the poor stability arising from the weak noncovalent interactions has obstructed their practical applications. Here, we report a robust and easily regenerated polyhedron-based cationic framework assembled from a metal-organic square. This material exhibits a very low affinity for CH4 and N2 , but captures other competing gases (e.g. C2 H6 , C3 H8 , and CO2 ) with a moderate affinity. These results underpin highly selective separation of a range of gas mixtures that are relevant to natural gas and industrial off-gas. Dynamic breakthrough studies demonstrate its practical separation for C2 H6 /CH4 , C3 H8 /CH4 , CO2 /N2 , and CO2 /CH4 . Particularly, the separation time is ≈11 min g-1 for the C2 H6 /CH4 (15/85 v/v) mixture and ≈49 min g-1 for the C3 H8 /CH4 (15/85 v/v) mixture (under a flow of 2.0 mL min-1 ), respectively, enabling its capability for CH4 purification from light alkanes.

Photoluminescence of Lanthanide-Titanium-Oxo Clusters Eu9Ti2 and Tb9Ti2 Based on a ß-Diketone Ligand.

A series of acetylacetone-protected lanthanide-titanium-oxo clusters (LTOCs), formulated as [La6Ti(µ3-OH)8(acac)12(CH3O)2(CH3OH)6] (La6Ti; Hacac = acetylacetone) and [Ln9Ti2(µ4-O)(µ3-OH)14(acac)17(CH3O)2(CH3OH)3] [Ln = Eu (Eu9Ti2) and Tb (Tb9Ti2)], were synthesized through the reactions of LnCl3·6H2O (Ln = La, Eu, and Tb), Hacac, Ti(OiPr)4, and triethylamine in methanol. Crystal structural analysis shows that La6Ti exhibits an hourglass-like structure consisting of two La3Ti cubane subunits by sharing one Ti4+ ion, while Eu9Ti2 can be viewed as a combination of four Eu3Ti cubane subunits by sharing three corners and one side. The photoluminescence (PL) measurements show that Tb9Ti2 exhibits excellent PL properties with a high quantum yield (QY) of 34.8%, while Eu9Ti2 only has a QY of 1.4% because of the different photosensitizations of ligands to Eu3+ and Tb3+ ions in the photophysical process.

Magnetic 3d-4f Chiral Clusters Showing Multimetal Site Magneto-Chiral Dichroism.

Here, we report the molecular self-assembly of hydroxido-bridged {Ln5Ni6} ((Ln3+ = Dy3+, Y3+) metal clusters by the reaction of enantiopure chiral ligands, namely, (R/S)-(2-hydroxy-3-methoxybenzyl)-serine), with NiII and LnIII precursors. Single-crystal diffraction analysis reveals that these compounds are isostructural sandwich-like 3d-4f heterometallic clusters showing helical chirality. Direct current magnetic measurements on {Dy5Ni6} indicates ferromagnetic coupling between DyIII and NiII centers, whereas those on {Y5Ni6} denote that the NiII centers are antiferromagnetically coupled and/or magnetically anisotropic. Magneto-chiral dichroism (MChD) measurements on {Dy5Ni6} and its comparison to that of {Y5Ni6} provide the first experimental observation of intense multimetal site MChD signals in the visible-near-infrared region. Moreover, the comparison of MChD with natural and magnetic circular dichroism spectra unambiguously demonstrate for the first time that the MChD signals associated with the NiII d-d transitions are mostly driven by natural optical activity and those associated with the DyIII f-f transitions are driven by magnetic optical activity.

Association between miRNA-499 gene polymorphism and autoimmune diseases: A meta-analysis.

INTRODUCTION: The association between miRNA-499 rs3746444 and a variety of autoimmune diseases has been reported. However, these results were contradictory and just focused on one or two autoimmune diseases. The present study aims to examine the possible association between rs3746444 polymorphism and the risk of autoimmune diseases. METHODS: The studies that evaluated the association between miRNA-499 gene polymorphism and autoimmune diseases were retrieved. Five different genetic models were used to evaluate the association. The random-effects model was used to pool the effect sizes. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the associations. Stratification analyses were performed by ethnicity and type of autoimmune diseases. False-positive report probability (FPRP) was performed for determining noteworthy associations. RESULTS: Seventeen articles (twenty studies) involving 4,376 cases and 4,991 controls were identified and included in our meta-analysis. The pooled ORs of all eligible case-control studies indicated a significant association between miRNA-499 gene polymorphism and autoimmune diseases: (T vs. C: OR = 0.877; 95% CI: 0.774, 0.993; P = 0.039). Stratified analysis indicated a significant association across both Caucasian (TT vs. TC+CC: OR = 0.779; 95% CI: 0.622, 0.976; P = 0.030) and Asian (T vs. C: OR = 0.895; 95% CI: 0.808, 0.992; P = 0.035) populations. There was also a significant association in Behcet's disease, rheumatoid arthritis, systemic lupus erythematosus, and ulcerative colitis populations. CONCLUSIONS: Our meta-analysis suggested that the miRNA-499 rs3746444 polymorphism was associated with an elevated risk of autoimmune diseases in the overall analysis as well as Caucasian and Asian populations.