Dielectric barrier discharge plasma grafting carboxylate groups on Pt/Al2O3 catalysts for highly efficient hydrogen release from perhydro-dibenzyltoluene

The key issues for the use of dibenzyltoluene (DBT) as a Liquid Organic Hydrogen Carrier (LOHC) are the high dehydrogenation temperature and the sluggish hydrogen releasing rate. Therefore, highly active...

The Effect of Chemical Activating Agent on the Properties of Activated Carbon from Sago Waste

The effect of chemical activators on the properties of activated carbon from sago waste was conducted in this study by using ZnCl2, H3PO4, KOH, and KMnO4 chemical solutions. The carbonized sago waste was added to each chemical solution, boiled at 85 °C for 4 h, and heated at 600 °C for 3 h. The porosity, microstructural, proximate, and surface chemistry analyses were carried out using nitrogen adsorption with employing the Brunauer Emmett Teller (BET) method and the Barret-Joyner-Halenda (BJH) calculation, scanning electron microscopy by using energy dispersive spectroscopy, X-ray diffractometer, simultaneous thermogravimetric analysis system, and the Fourier-transform infrared spectroscopy. The results showed that the activated carbon prepared using ZnCl2 acid had the highest specific surface area of 546.61 m2/g, while the KOH activating agent surpassed other chemicals in terms of a refined structure and morphology, with the lowest ash content of 10.90%. The surface chemistry study revealed that ZnCl2 and KOH activated carbon showed phenol and carboxylate groups. Hence, ZnCl2 acid was suggested as activating agents for micropore carbon, while KOH was favorable to producing a mesopore-activated carbon from sago waste.

Adsorption of Iron with Biosorbents derived from Longan Peel, Pomelo Peel and Jackfruit Peel

High iron (Fe2+) concentration in groundwater is a severe issue in many regions of the world. This study attempts to investigate the effectiveness of biosorbents derived from longan peel (LP), pomelo peel (PP) and jackfruit peel (JP) for the adsorption of Fe2+ from aqueous solution in various forms. A batch adsorption study was carried out with an initial Fe2+ concentration of 10 mg/L for 2 h. The results showed that the highest removal efficiency was achieved for PP and its biochar at 97.38% and 99.45%, respectively. High removal efficiency implied that PP contained favourable characteristics for the adsorption of Fe2+. Under the scanning electron microscope (SEM), the surface structure of PP displayed visible dimensions with a relatively large pore size compared with LP and JP. Characterisation study using Fourier-transform infrared spectroscopy (FTIR) reveals that the carboxylate groups and ester carbonyl band participated in the adsorption process. At higher initial pH of 5.83, adsorption of Fe2+ using PP gives higher removal efficiency due to lower competition on electrostatic interaction between positive ions in the solution and the surface of biosorbents. Furthermore, adsorption uptake of 83.0 mg/g was attainable with an initial concentration of 100 mg/L. This study has proven the feasibility of PP as a low cost biosorbents for removing Fe2+ in an aqueous solution.

Study on Reduction of 4-nitrophenol by Magnetic Maize Straw Supported with Copper Nanoparticles

In this work, magnetic maize straw was prepared by the amidation process using renewable maize straw as starting material. After magnetic succinylated maize straw (Mag-S-MS) was mixed with cupric ions aqueous solution, Cu (II) could be captured by the amino and carboxylate groups. Then, the bonded Cu (II) was converted to valuable Cu nanoparticles (Cu NPS). It was characterized by SEM-EDS, XRD, XPS, and TGA, which indicated Cu NPS were formed successfully on Mag-S-MS without self-aggregation and oxidation. The above nanocomposites could be employed as a catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The effect of the dosage of Cu NPS loaded-Mag-S-MS, the initial concentrations of NaBH4 and 4-NP were investigated, and a possible mechanism was discussed. The catalyst maintained relatively high catalytic activity after five cycle tests. Due to its superparamagnetic nature, it could be quickly collected from the aqueous solution under a magnetic field. These results could provide a method for using agricultural waste in nano catalytic reaction.

The β-lactam Ticarcillin is a Staphylococcus aureus UDP-N-acetylglucosamine 2-epimerase binder.

Infectious diseases account for 25% of the causes of death worldwide and this rate is expected to increase with the increasing rate of antibiotic resistance observed for many pathogens. Among the bacterial pathogens usually found in healthcare associated infections, Escherichia coli and Staphylococcus aureus are the most prevalent pathogens and, for the former, about 50% of the isolates are found to be methicillin resistant. Given the limited number of targets/pathways observed for the mechanism of action for the existing antibiotics, the discovery of newer targets and their evaluation becomes an urgent and necessary task. Here we describe the structure-based identification of ticarcillin as a weak binder of the UDP-N-acetylglucosamine 2-epimerase (MnaA) from S. aureus. After a docking-based screening of existing drugs, ticarcillin was identified as a ligand in isothermal analysis of differential scanning fluorimetry data. An equilibrium molecular dynamics simulation confirmed the docking binding mode as a stable pose, with large contributions to the binding energy coming from interactions between Arg206 and Arg207 and the carboxylate groups in ticarcillin.

A new two-dimensional folding sheet-like coordination polymer assembled from cadmium(II) and (S)-2-(benzylamino)succinic acid: synthesis, structure and properties

A new two-dimensional (2D) coordination polymer, namely, poly[[diaqua[μ3-(S)-2-(benzylamino)succinato-κ4 N,O 1:O 1′:O 4]cadmium(II)] monohydrate], {[Cd(C11H11NO4)(H2O)2]·H2O} n , has been synthesized by the solvothermal reaction of Cd(CH3COO)2·2H2O with the synthesized ligand (S)-2-(benzylamino)succinic acid (H2 L). The title compound has been structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction analysis. In the crystal structure, each CdII cation binds to three carboxylate groups from three symmetry-related L 2− dianions. The tetradentate L 2− ligand links three symmetry-related CdII cations into a 2D folding sheet, which can be simplified as a uninodal (3,3)-connected hcb net with the point symbol (63). In the lattice, all the folding sheets are arranged in an interdigitated fashion and aggregate into zipper-like arrays through interlayer π–π interactions. The large and nonpolar side chain may play an important role in the formation and aggregation of the 2D sheet. The thermal stability and photoluminescence properties of the title compound were investigated, and it exhibits a blue emission with a quantum yield of 8%.

Crystal structure, Hirshfeld surface analysis and DFT studies of tetrakis(μ-3-nitrobenzoato-κ2 O 1:O 1′)bis[(N,N-dimethylformamide-κO)copper(II)] dimethylformamide disolvate

The title compound, [Cu2(C7H4NO4)4(C3H7NO)2]·(C3H7NO)2, is a binuclear copper(II) complex located on an inversion center midway between the two copper(II) cations. The asymmetric unit consists of one CuII cation, two 3-nitrobenzoato ligands, and two dimethylformamide (DMF) molecules, one of which coordinates to the CuII cation and one is a solvate molecule. The carboxylate groups of the ligands bridge two CuII cations with a Cu—Cu distance of 2.6554 (6) Å, completing a distorted octahedral O5Cu coordination environment. The dihedral angles between the carboxylate and the aromatic ring planes of the two independent ligands are different from one another, viz. 5.2 (3) and 23.9 (3)°. The three-dimensional structure is consolidated by weak C—H...O interactions and stabilized by π–π stacking interactions between the aromatic rings. The complex and the free ligand were further characterized by Fourier-transform infrared spectroscopy (FT–IR), and the energies of the frontier molecular orbitals of the complex were determined by DFT calculations at the B3LYP/def2-TZVP level of theory.

Low-temperature phases of dicalcium barium hexakis(propanoate)

The structure determinations of phases (II) and (III) of barium dicalcium hexakis(propanoate) {or poly[hexa-μ4-propanoato-bariumdicalcium], [BaCa2(C3H5O2)6] n } are reported at 240 and 130 K, respectively [phase (I) was determined previously by Stadnicka & Glazer (1980). Acta Cryst. B36, 2977–2985; our structure determination of phase (I) at room temperature is included in the supporting information]. In the high-temperature phase, the Ba2+ cation is surrounded by six carboxylate groups in bidentate bridging modes. In the low-temperature phases, five carboxylate groups act in bidentate bridging modes and one acts in a monodentate bridging mode around Ba2+. The Ca2+ cations are surrounded by six carboxylate O atoms in a trigonal antiprism in all the structures. The Ba2+ and Ca2+ cations are underbonded and significantly overbonded, respectively, in all the phases. The bonding of the Ba2+ cation increases slightly at the cost of the bonding of Ca2+ cations during cooling to the low-temperature phases. The phase transitions during cooling are accompanied by ordering of the ethyl chains. In room-temperature phase (I), all six ethyl chains are positionally disordered over two positions in the crossed mode, with additional splitting of the ethyl α- and β-C atoms. In phase (II), on the other hand, there are three disordered ethyl chains, one with positionally disordered ethyl α- and β-C atoms, and the other two with positionally disordered ethyl β-C atoms only, and in the lowest-temperature phase (III) there are four ordered ethyl chains and two disordered ethyl chains with positionally disordered ethyl β-C atoms only.

A two-dimensional calcium (II) coordination polymer constructed from 2,2′-[terephthaloylbis(azanediyl)]diacetate: synthesis, structure and properties

A new two-dimensional (2D) coordination polymer, namely, poly[[diaqua-[μ4-2,2′-[terephthaloylbis(azanediyl)]diacetato]calcium(II)] monohydrate], {[Ca(C12H10N2O6)(H2O)2]·H2O} n , (I), has been synthesized by the reaction of CaCl2 with 2,2′-[terephthaloylbis(azanediyl)]diacetic acid (H2 L). The title compound was structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. In the crystal structure of (I), each CaII cation binds to six carboxylate groups from four symmetry-related L 2− dianions. The hexadentate L 2− ligand links four symmetry-related calcium cations into a 2D layer-like structure, which can be simplified as a uninodal SP 2-periodic (3,6)III net with the point symbol (43·63). In the lattice, all layers pack in parallel arrays through weak interlayer hydrogen bonding and π–π interactions. The thermal stability and photoluminescence properties of (I) have been investigated. Thermogravimetric analysis reveals the different thermal stabilities of the two coordinated water molecules due to their different hydrogen-bonding interactions. The title coordination polymer exhibits an excitation-wavelength-dependent fluorescence in the solid state.

Thermostability-based binding assays reveal complex interplay of cation, substrate and lipid binding in the bacterial DASS transporter, VcINDY.

The divalent anionsodium symporter (DASS) family of transporters (SLC13 family in humans) are key regulators of metabolic homeostasis, disruption of which results in protection from diabetes and obesity, and inhibition of liver cancer cell proliferation. Thus, DASS transporter inhibitors are attractive targets in the treatment of chronic, age-related metabolic diseases. The characterisation of several DASS transporters has revealed variation in the substrate selectivity and flexibility in the coupling ion used to power transport. Here, using the model DASS co-transporter, VcINDY from Vibrio cholerae, we have examined the interplay of the three major interactions that occur during transport: the coupling ion, the substrate, and the lipid environment. Using a series of high-throughput thermostability-based interaction assays, we have shown that substrate binding is Na+-dependent; a requirement that is orchestrated through a combination of electrostatic attraction and Na+-induced priming of the binding site architecture. We have identified novel DASS ligands and revealed that ligand binding is dominated by the requirement of two carboxylate groups in the ligand that are precisely distanced to satisfy carboxylate interaction regions of the substrate binding site. We have also identified a complex relationship between substrate and lipid interactions, which suggests a dynamic, regulatory role for lipids in VcINDY’s transport cycle.