Gradual Size Enlargement of Aluminum-Oxo Clusters and the Photochromic Properties

Metallic clusters, assembled by functional motifs, possess the attribute of regulating the properties by changing inorganic and organic components. In this work, a series of aluminum-oxo clusters, [Al6O(dmp)4(Hdmp)2]·2iPrOH [Al6-1, H3dmp = 2,2-bis(hydroxymethyl)propionic acid], [Al6(H2thmmg)6]·2DMF·2H2O [Al6-2, H5thmmg = N-tris(hydroxymethyl)methylglycine], [Al8(OH)4(NAP-OH)12(MeO)7(MeOH)]Cl·7MeCN·3MeOH (Al8, HNAP-OH = 3-hydroxy-2-naphthoic acid), and [Al10(NA)10(MeO)20] (Al10, HNA = nicotinic acid), were obtained based on different carboxylic acids, realizing metallic ring size enlargement from 5.91 to 9.32 Å. They all exhibit good chemical stability. Importantly, the Al8 cluster displays obvious photochromic behavior from pale yellow to orange yellow, originating from the generation of photoinduced radicals in the metal-assisted ligand–ligand electron transfer process of 3-hydroxy-2-naphthoic acid (HNAP-OH). This work enriches the metal ring cluster chemistry and reports the example of the aluminum-oxo cluster-based photochromic material, developing a novel system of photochromic materials

Multicolor Phosphorescence Modulated by Excitation and Temperature in Zn-Based Coordination Polymers

Color-tunable room-temperature phosphorescence (RTP) with potential in many fields is of great importance but extremely challenging. It is necessary to comprehend the correlation between the molecular structure and property to design and synthesize such materials. Metal–organic coordination polymers (CPs) with good predesignability and precise structure have become a platform to construct RTP materials. Herein, three zinc-based CPs containing halogen and a flexible tetradentate ligand are synthesized. All of these CPs present two constant emission regions and an excitation-dependent emission region. Structure–property analysis shows that these emissions originate from isolated chromophores and dimerized chromophores as well as various charge transfers. The phosphorescence colors of these CPs can be modulated by excitation and temperature. This study provides a novel strategy to construct multicolor and multiresponsive RTP materials based on metal–organic coordination polymers

Dual Ligand Strategy for Constructing a Series of d¹⁰ Coordination Polymers: Syntheses, Structures, Photoluminescence, and Sensing Properties

Constructed from a rigid pyrazine-tetrazole ligand, 5-(pyrazinyl)­tetrazole (Hptz), and various polycarboxylate molecules, a series of novel Zn­(II)/Cd­(II) coordination polymers, [Cd­(Hptz)­(Hbtc)­(H₂O)₂·H₂O]_<i>n</i> (<b>1</b>), [Cd₂(ptz)­(btc)­(H₂O)₂·2H₂O]_<i>n</i> (<b>2</b>), [Cd₂(ptz)₂(<i>p</i>-bdc)]_<i>n</i> (<b>3</b>), [Cd₂(ptz)₂(<i>m</i>-bdc)­(H₂O)]_<i>n</i> (<b>4</b>), [Zn₂(ptz)­(btc)­(H₂O)₂·H₂O]<i>_n</i> (<b>5</b>), and [Cd₂(ptz)­(btc)­(DMA)­(H₂O)·4.5H₂O]_<i>n</i> (<b>6</b>) (H₃btc = 1,3,5-benzenetricarboxylic acid, <i>p</i>-H₂bdc = <i>p</i>-phthalic acid, <i>m</i>-H₂bdc = <i>m</i>-phthalic acid, DMA = <i>N</i>,<i>N</i>-dimethylacetamide), have been obtained under hydrothermal or solvothermal conditions. The structural diversity of <b>1</b>–<b>6</b> mainly stems from the different and various coordination modes of the N-donor ligand, as different chelating or bridging/chelating fashions have generated various structures with one-, two-, or three-dimensions. Both π–π stacking interactions could be observed in adjacent chains and layers for <b>1</b> and <b>2</b>, respectively, through which leads to 3D supramolecular frameworks. Differently, the 3D complicated architectures are constructed in <b>3</b>–<b>6</b> through the linkage of metal centers and organic ligands. All of these interesting structures have been determined and characterized by single-crystal X-ray diffraction analyses. Photoluminescence properties of compounds <b>1</b>–<b>6</b> have been investigated. Moreover, a photoluminescence sensing experiment indicates that compounds <b>1</b> and <b>6</b> can act as promising selective sensors toward Cu²⁺

Template-directed syntheses of two 3D metal oxalates: <i>in situ</i> N-methylation and crystal structures

<p>Two isomorphic organically templated zinc/cobalt oxalates, (dmdabco)[Zn₂(C₂O₄)₃]·4H₂O (<b>1</b>), and (dmdabco)[Co₂(C₂O₄)₃]·4H₂O (<b>2</b>) (C₂O₄²⁻ = oxalate; dmdabco = N,N′-dimethyl-1,4-diazabicyclo[2,2,2]octane), have been prepared under solvothermal conditions and characterized by X-ray structural analyses. The dmdabco²⁺ templating agent was derived from simple <i>in situ</i> N-alkylation between methanol and 1,4-diazabicyclo[2,2,2]octane (dabco). Distinct from conventional <i>Eschweiler</i>-<i>Clarke</i> methylation containing excess formic acid and formaldehyde, such one-step methylation from methanol molecules is convenient. Both <b>1</b> and <b>2</b> exhibit a uninodal 3-connected 3-D interrupted open-framework, in which oxalate ligands have <i>in</i>-<i>plane</i> and <i>out</i>-<i>of</i>-<i>plane</i> connection modes.</p

3D Inorganic Cuprous Iodide Open-Framework Templated by In Situ <i>N</i>‑Methylated 2,4,6-Tri(4-pyridyl)-1,3,5-triazine

A novel 3D inorganic cuprous iodide framework templated by in situ <i>N</i>-methylated 2,4,6-tri­(4-pyridyl)-1,3,5-triazine (TPT) was solvothermally prepared and structurally characterized. The title compound bearing chiral cuprous iodide chains as building units is the first 3D extended framework with the TPT-derivatives as template. The UV–vis diffuse-reflectance measurement reveals that <b>1</b> possesses semiconductor behavior with band gaps of 1.35 eV. The photoluminescent property of <b>1</b> has also been studied

YSO₄F·H₂O: A Deep-Ultraviolet Birefringent Rare-Earth Sulfate Fluoride with Enhanced Birefringence Induced by Fluorinated Y‑Centered Polyhedra

Birefringent crystals can modulate and detect the polarization of light and are important optical functional materials. The birefringence is positively correlated to the anisotropy of the structure. By partially substituting sulfate anion with large electronegative fluorine in the parent compound Y2(SO4)3·8H2O, a new fluorinated rare-earth sulfate YSO4F·H2O with enhanced anisotropy was achieved. YSO4F·H2O features a dense 3D structure constructed by the polarizable [YOF] polyhedra and [SO4] tetrahedra. The diffuse reflectance spectrum reveals that it has a short UV absorption edge of below 200 nm. The substitution of the F– ion enhances the optical anisotropy, making the material exhibit an enhanced birefringence (0.0357 at 546 nm), which is 5.1 times that of the parent compound and is also larger than most deep-UV birefringent sulfates. It is expected that this work may shed useful insights in the exploration of deep-UV birefringent materials with enhanced optical performances.

Large Heterometallic Dy₁₂Na₆ Cage-like Cluster Supported by in Situ Generated Ligand

A novel heterometallic cluster, Dy₁₂Na₆, has been prepared and characterized. It represents an unprecedented high-nuclearity alkali-metal-Ln cluster with a cage-like shape. In situ generated ligands participated in the formation of the heterometallic cluster. Magnetic measurements suggest that Dy₁₂Na₆ shows slow magnetic relaxation at low temperature

Two Cobalt-diphosphonates Templated by Long-Chain Flexible Amines: Synthesis, Structures, Proton Conductivity, and Magnetic Properties

Two new cobalt-diphosphonates templated by protonated 1,2-bis­(3-aminopropylamino)­ethane (BAPEN), (C₈N₄H₂₆)_0.5·[Co­(HEDP)]·H₂O (<b>1</b>) and (C₈N₄H₂₆)·[Co₂(HEDP)₂(H₂O)₂]·5H₂O (<b>2</b>), were hydrothermally prepared (HEDP = CH₃C­(OH)­(PO₃)₂, 1-hydroxyethylidenediphosphonate). Compounds <b>1</b> and <b>2</b> exhibit anionic 1D Co-HEDP chain and 2D Co-HEDP layer structure, respectively. The structure diversities from 1D chain to 2D layer was realized by adjusting the synthetic parameters. Their magnetism and proton conduction have been studied. Magnetic measurements indicated that the title compounds exhibit weak magnetic interactions. Compounds <b>1</b> and <b>2</b> feature a proton conductivity of 3.57 × 10^–4 and 9.43 × 10^–5 S cm^–1 at 100% relative humidity and 65 °C, respectively

Image_1_(–)-Epigallocatechin-3-Gallate Ameliorates Atherosclerosis and Modulates Hepatic Lipid Metabolic Gene Expression in Apolipoprotein E Knockout Mice: Involvement of TTC39B.PDF

<p>Background: Aberrant chronic inflammation and excess accumulation of lipids play a pivotal role in the occurrence and progression of atherosclerosis. (–)-Epigallocatechin-3-gallate (EGCG), the major catechins in green tea, displayed anti-atherosclerotic properties in vivo and in vitro. However, the effects and underlying mechanism of EGCG on atherosclerosis remain unclear.</p><p>Methods: Male apolipoprotein E-knockout (ApoE^-/-) mice (7 weeks old) fed with high-fat diet (HFD) were treated with normal saline or EGCG (40 mg/kg/d, i.g.) for 18 weeks. Atherosclerotic plaque and liver lipid accumulation were measured by Oil Red staining. Plasma lipids and cytokines were detected using commercial kits. The expression of protein and mRNA was analyzed by western blot and quantitative real-time reverse transcription-polymerase chain reaction, respectively.</p><p>Results: EGCG administration markedly attenuated atherosclerotic plaque formation in HFD-fed ApoE^-/- mice, which were accompanied by increased plasma interleukin-10 (IL-10) level and decreased plasma IL-6 and tumor necrosis factor-α (TNF-α) levels. In addition, EGCG modulated high-fat-induced dyslipidemia, evidencing by decreased total cholesterol (TC) and low-density lipoprotein levels and increased high-density lipoprotein level. Meanwhile, EGCG treatment alleviated high-fat-mediated liver lipid accumulation and decreased liver TC and triglyceride. Mechanistically, EGCG significantly modulated high-fat-induced hepatic tetratricopeptide repeat domain protein 39B (TTC39B) expression and its related genes (Lxrβ, Abcg5, Abcg8, Abca1, Srebf1, Scd1, Scd2, Fas, Elovl5, Mylip) expression in liver from ApoE^-/- mice. Notably, EGCG remarkably induced hepatic liver X receptor α (LXRα) and LXRβ expression and inhibited both precursor and mature sterol regulatory element binding transcription factor-1 (SREBP-1) expression.</p><p>Conclusion: Taken together, our data for the first time suggested that TTC39B was involved in EGCG-mediated anti-atherosclerotic effects through modulation of LXR/SREBP-1 pathway.</p

Genetic and Cytological Analysis of a Novel Type of Low Temperature-Dependent Intrasubspecific Hybrid Weakness in Rice

<div><p>Hybrid weakness (HW) is an important postzygotic isolation which occurs in both intra- and inter-specific crosses. In this study, we described a novel low temperature-dependent intrasubspecific hybrid weakness in the F₁ plants derived from the cross between two <i>indica</i> rice varieties Taifeng A and V1134. HW plants showed growth retardation, reduced panicle number and pale green leaves with chlorotic spots. Cytological assay showed that there were reduced cell numbers, larger intercellular spaces, thicker cell walls, and abnormal development of chloroplast and mitochondria in the mature leaves from HW F₁ plants in comparison with that from both of the parental lines. Genetic analysis revealed that HW was controlled by two complementary dominant genes <i>Hw3</i> from V1134 and <i>Hw4</i> from Taifeng A. <i>Hw3</i> was mapped in a 136 kb interval between the markers Indel1118 and Indel1117 on chromosome 11, and <i>Hw4</i> was mapped in the region of about 15 cM between RM182 and RM505 on chromosome 7, respectively. RT-PCR analysis revealed that only <i>LOC_Os11g44310</i>, encoding a putative calmodulin-binding protein (<i>OsCaMBP</i>), differentially expressed among Taifeng A, V1134 and their HW F₁. No recombinant was detected using the markers designed based on the sequence of <i>LOC_Os11g44310</i> in the BC₁F₂ (Taifeng A//Taifeng A/V1134) population. Hence, <i>LOC_Os11g44310</i> was probably the candidate gene of <i>Hw3</i>. Gene amplification suggested that <i>LOC_Os11g44310</i> was present in V1134 and absent in Taifeng A. BLAST search revealed that <i>LOC_Os11g44310</i> had one copy in the <i>japonica</i> genomic sequence of Nipponbare, and no homologous sequence in the <i>indica</i> reference sequence of 9311. Our results indicate that <i>Hw3</i> is a novel gene for inducing hybrid weakness in rice.</p></div