A series of 1-D, 2-D and 3-D coordination polymers self-assembled from a flexible dicarboxylate and mixed N-donor ligands: syntheses, structural diversity, and luminescent properties

<p>We have synthesized a series of metal–organic coordination frameworks under solvothermal conditions, formulated as [Cu(L)(phen)](<b>1</b>), [Co₂(L)₂(bib)]·CH₃OH(<b>2</b>), [Co(L)(btmb)_0.5](<b>3</b>), [Zn(L)(bib)]·2H₂O(<b>4</b>), [Cu(L)(bib)]·DMF(<b>5</b>), and [Mn₄(L)₄(bimb)(CH₃OH)](<b>6</b>) based on a flexible multicarboxylic bridging ligand 4,4′-methylenebis(oxy)-dibenzoic acid (H₂L) and flexible N-donor ligands 1,4-bis (1H-imidazol-1-yl)-butane (bib), 1,4-bis(1H-1,2,4-triazol- 1-ylmethyl)benzene (btmb), and 1,4-bis(1H-imidazol-1-ylmethyl)benzene (bimb). The structures of the frameworks have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The crystal structure determinations reveal that <b>1</b> has a 1-D Z-shape chain. Compounds <b>2</b> and <b>3</b> are 2-D twofold parallel interpenetrating 4-connected net with the Schläfli symbol {4⁴·6²}. Compound <b>4</b> is a 2-D threefold parallel interpenetrating 4-connected nets with the Schläfli symbol {4⁴·6²}. Compound <b>5</b> is 3-D 4-connected net with the Schläfli symbol {6⁵·8}. Compound <b>6</b> is characterized by a three-dimensional framework with one-dimensional homogeneous Mn-carboxylate chain. We found that flexible carboxylate ligands have different coordination modes under different synthetic conditions. The flexible skeleton of ligands and the coordination angle between the ligand and the metal ion is described. The luminescence and thermogravimetric properties of these compounds have been investigated.</p

Synthesis of the Insecticide Prothrin and Its Analogues from Biomass-Derived 5‑(Chloromethyl)furfural

Prothrin, a synthetic pyrethroid insecticide, was synthesized from the biomass-derived platform chemical 5-(chloromethyl)­furfural in six steps and overall 65% yield. Two structural analogues of prothrin were also prepared following the same synthetic approach. Preliminary testing of these furan-based pyrethroids against the yellow fever mosquito Aedes aegypti indicates promising insecticidal activities

Additional file 1: Table S1. of Light induced expression of β-glucosidase in Escherichia coli with autolysis of cell

Bacterial strains and plasmids used in this study. Table S2. Oligo nucleotides used in this work. Table S3. Expression of prokaryotic β-glucosidase. Figure S1. SDS-PAGE of Bgl1A(A24S/F297Y) expression and cell autolysis induced with lactose in HCDC. (DOCX 3264 kb

Barium Hydride-Mediated Nitrogen Transfer and Hydrogenation for Ammonia Synthesis: A Case Study of Cobalt

Industrial ammonia synthesis catalyzed by Fe- and Ru-based catalysts is an energy-consuming process. The development of low-temperature active catalyst has been pursued for a century. Herein, we report that barium hydride (BaH₂) can synergize with Co, leading to a much better low-temperature activity, i.e., the BaH₂-Co/carbon nanotube (CNT) catalyst exhibits ammonia synthesis activity right above 150 °C; at 300 °C, it is 2 orders of magnitude higher than that of the BaO-Co/CNTs and more than 2.5-times higher than Cs-promoted Ru/MgO. Kinetic analyses reveal that the dissociative adsorption of N₂ on the Co-BaH₂ catalyst may not be the rate-determining step, as evidenced by the much smaller reaction order of N₂ (0.43) and the lower apparent activation energy (58 kJ mol^–1) compared with those of the unpromoted and BaO-promoted Co-based catalysts. BaH₂, with a negative hydride ion, may act as a strong reducing agent, removing activated N from the Co surface and forming a BaNH species. The hydrogenation of the BaNH species to NH₃ and BaH₂ can be facilely carried out at 150 °C. The relayed catalysis by Co and BaH₂ sites creates an energy-favored pathway that allows ammonia synthesis under milder conditions

Kartogenin-Incorporated Thermogel Supports Stem Cells for Significant Cartilage Regeneration

Recently, cartilage tissue engineering (CTE) attracts increasing attention in cartilage defect repair. In this work, kartogenin (KGN), an emerging chondroinductive nonprotein small molecule, was incorporated into a thermogel of poly­(l-lactide-<i>co</i>-glycolide)–poly­(ethylene glycol)–poly­(l-lactide-<i>co</i>-glycolide) (PLGA–PEG–PLGA) to fabricate an appropriate microenvironment of bone marrow mesenchymal stem cells (BMSCs) for effective cartilage regeneration. More integrative and smoother repaired articular surface, more abundant characteristic glycosaminoglycans (GAGs) and collagen II (COL II), and less degeneration of normal cartilage were obtained in the KGN and BMSCs coloaded thermogel group in vivo. In conclusion, the KGN-loaded PLGA–PEG–PLGA thermogel can be utilized as an alternative support for BMSCs to regenerate damaged cartilage in vivo

Oxidation activity of Lac15D for PPD, OPD, OAP, DMP, and PAP under different pHs.

<p>Oxidation activity of Lac15D for PPD, OPD, OAP, DMP, and PAP under different pHs.</p

Morphological features of synovium.

<p>Morphological features of synovium.</p

Relative activity of Lac51 towards lignin-related phenolic compounds at 38°C and optimum pH.

<p>Relative activity of Lac51 towards lignin-related phenolic compounds at 38°C and optimum pH.</p

Effects of Alkaline Earth Metal Amides on Ru in Catalytic Ammonia Decomposition

The effects of alkaline earth metal amides (Mg­(NH₂)₂, Ca­(NH₂)₂, and Ba­(NH₂)₂) on Ru in catalyzing NH₃ decomposition were investigated. The catalytic activities rank in the order of Ru–Ba­(NH₂)₂ > Ru–Ca­(NH₂)₂ > Ru–Mg­(NH₂)₂, among which Ru–Ba­(NH₂)₂ and Ru–Ca­(NH₂)₂ catalysts have higher intrinsic activities (TOF) and lower apparent activation energies than those of Ru–Mg­(NH₂)₂ and Ru/MgO catalysts, indicating that Ca­(NH₂)₂ and Ba­(NH₂)₂ may have different roles from those of Mg­(NH₂)₂ and MgO. The TPR (temperature-programmed reaction) results show that Ca­(NH₂)₂ or Ba­(NH₂)₂ decomposes to N₂ and H₂ rather than NH₃ in the presence of Ru. Ru may promote the NH_<i>x</i> (<i>x</i> = 1, 2) coupling to H₂ and N₂ and change the decomposition pathways of Ca­(NH₂)₂ and Ba­(NH₂)₂. Kinetic analyses reveal that the Ru promoted NH_<i>x</i> coupling to H₂ and N₂ may be the rate-determining step for catalytic ammonia decomposition. We suggest that the catalysis is very likely fulfilled via (1) Ru catalyzes the decomposition of amides to form H₂, N₂, and imides through an energy more favorable pathway and (2) imides react with NH₃ to regenerate amides. The presence of Ca­(NH₂)₂ or Ba­(NH₂)₂ creates a NH_<i>x</i>-rich environment, and Ru mediates the electron transfer from NH_<i>x</i> to facilitate NH_<i>x</i> coupling to N₂ and H₂

Evidence for Lignin Oxidation by the Giant Panda Fecal Microbiome

<div><p>The digestion of lignin and lignin-related phenolic compounds from bamboo by giant pandas has puzzled scientists because of the lack of lignin-degrading genes in the genome of the bamboo-feeding animals. We constructed a 16S rRNA gene library from the microorganisms derived from the giant panda feces to identify the possibility for the presence of potential lignin-degrading bacteria. Phylogenetic analysis showed that the phylotypes of the intestinal bacteria were affiliated with the phyla <em>Proteobacteria</em> (53%) and <em>Firmicutes</em> (47%). Two phylotypes were affiliated with the known lignin-degrading bacterium <em>Pseudomonas putida</em> and the mangrove forest bacteria. To test the hypothesis that microbes in the giant panda gut help degrade lignin, a metagenomic library of the intestinal bacteria was constructed and screened for clones that contained genes encoding laccase, a lignin-degrading related enzyme. A multicopper oxidase gene, designated as <em>lac51</em>, was identified from a metagenomic clone. Sequence analysis and copper content determination indicated that Lac51 is a laccase rather than a metallo-oxidase and may work outside its original host cell because it has a TAT-type signal peptide and a transmembrane segment at its N-terminus. Lac51 oxidizes a variety of lignin-related phenolic compounds, including syringaldazine, 2,6-dimethoxyphenol, ferulic acid, veratryl alcohol, guaiacol, and sinapinic acid at conditions that simulate the physiologic environment in giant panda intestines. Furthermore, in the presence of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), syringic acid, or ferulic acid as mediators, the oxidative ability of Lac51 on lignin was promoted. The absorbance of lignin at 445 nm decreased to 36% for ABTS, 51% for syringic acid, and 51% for ferulic acid after incubation for 10 h. Our findings demonstrate that the intestinal bacteria of giant pandas may facilitate the oxidation of lignin moieties, thereby clarifying the digestion of bamboo lignin by the animal.</p> </div