In this article, two Ba(II) metal-organic frameworks(MOFs), {[Ba(BPS)(H2O)2]·H2O} n(1) and [Ba(BPS)(H2O)2] n(2)(H2BPS=4,4′-bibenzoic acid-2,2′-sulfone), were synthesized and characterized. X-Ray crystal structural analyses reveal that compounds 1 and 2 have different structures, which is probably related to different coordination modes of ligand in compounds 1 and 2. It is remarkable that compounds 1 and 2 both show excellent thermal stability. The solid-state emission spectra reveal that compounds 1 and 2 both present strong luminescence emission bands at room temperature.
Au nanoparticles loaded TiO2 hollow microspheres with exposed (001) facets(Au-HTFs) were synthesized through template-free hydrothermal process combined with a chemical reduction role. Au-HTFs displayed excellent photocatalytic activity in catalyzing oxidization reaction in organic pollutant system, which originates from the synergistic effect of the reactive (001) facets and Au nanoparticles with a wide range of absorption in visible region based on localized surface plasmon resonance effect. The unique synergistic effect could largely increase the photocatalytic performance resulting from the improvements of both the visible light aborption and the recombination of electron-hole pairs. Our findings revealed that among Au-HTFs with different Au loading percentages, Au-HTFs with 2%(mass fraction) Au loading possessed the superior photocatalytic activity.
BiOCl nanosheets with oxygen vacancies on the exposed {010} facets were assistant-synthesized by triethanolamine(TEOA) via hydrothermal method. We explored the surface properties, crystal structure, morphology and optical absorption ability of the prepared samples via various characterization technologies. The results indicate that the morphologies and microstructures of the obtained samples depend on the amount of TEOA in the synthesis. The addition of TEOA induces the production of oxygen vacancy on the surface of the samples. Therefore, the synthesized samples with TEOA-assistance hold higher photoactivity for the degradation of colorless antibiotic agent Ciprofloxacin(CIP) under visible light(λ⩾420 nm). The obtained sample upon the addition of 20 mL of TEOA exhibits the highest photocatalytic performance, which is nearly 14 times as high as that of the sample prepared without TEOA and twice as high as that of the prepared samples with NaOH or NH3·H2O. The possible degradation mechanism was discussed on the basis of the experiment results.
We reported the synthesis of Au130(SPh-Br)50(Br-Ph-SH=4-bromothiophenol) nanocluster with high purity and high yield via “size focusing” and “ligand exchange” processes. The time of synthetic process was significantly reduced compared with previous synthetic routine. Au130(SPh-Br)50 was determined by UV-Vis absorption spectros-copy and matrix-assisted laser desorption ionization(MALDI) mass spectroscopy. Thermo-gravimetric analysis (TGA) and size-exclusion chromatogram(SEC) analyses confirmed the purity of Au130(SPh-Br)50. The yield of gold nanoc-lusters was 20%(based on HAuCl4).
A three-dimentinal metal organic framework [Co2(L)Cl(DMF)2(H2O)](DMF)3(H2O)3 based on the nano-metresized ligand 4,4′,4″-[1,3,5-benzenetriyltris(carbonylimino)]trisbenzoic acid was synthesized, and characterized by means of single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetry analysis and magnetism. This obtained structure can be considered to be constructed from 2D layer, which displays the topology of hbc based on Co2(COO)3 secondary building unit, and further to be linked into a 3D supramolecular architecture by N—H···O hydrogen bonds. The magnetism of the complex was carried out, which shows ferromagnetic exchange interactions.
A general and efficient coupling of aryl bromides with diethyl malonate is presented. The reaction provided the α-arylated diethyl malonates in moderate to good yields with a low loading of CuCl2(5%, molar fraction) and 8-hydroxyquinoline(5%, molar fraction). This method has good compatibility for a wide range of aryl bromides.
A new steroidal sapogenin named 25-R-spirosta-3,5-dien-12β-ol(1) was isolated from the dried roots of Chlorophytum laxum R. Br. along with five known compounds, namely, diosgenin(2), stigmasterol(3), β-sitosterols(4), estigmasterol-3-O-β-D-glicopyranoside(5) and 3-O-β-authemisol(6). The structure of compound 1 was elucidated by the analysis of IR, HRESI-MS, 1D and 2D NMR spectral data. Compounds 2—5 were isolated from Chlorophytum laxum R. Br. In addition, all the compounds were evaluated for cytotoxicity on the human nasopharyngeal carcinoma cancer cell line 5-8F. Among them, the newly identified 25-R-spirosta-3,5-dien-12β-ol(1) and diosgenin(2) exhibited high cytotoxicity on 5-8F cells, with IC50 values of 24.8 and 41.9 μmol/L, respectively.
We report a modified process that dichloroketene generated in situ from trichloroacetyl chloride and Zn powder reacts with unreactivate carbonyl groups to afford dichloro-β-lactones in moderate to good yields. Subse-quently, monochloro-β-lactones, β-lactones and β-hydroxy ester are obtained by dechlorination under different reac-tion conditions.
To further explore the structure-activity relationship(SAR) of amide bridge moeity of anthranilic diamides derivatives, a series of N-pyridylpyrazole derivatives was designed, synthesized and their biological activities were evaluated. The chemical structures of novel target compounds were confirmed by 1H nuclear magnetic resonance (NMR), 13C NMR and elemental analyses(EA). Bioassay results of insecticidal activity demonstrated that the target compound 6h displayed 70% lethality rate against oriental armyworms at 200 mg/L. Moreover, most compounds displayed moderate to excellent antifungicidal activities against Fusarium oxysporum f. sp. cucumerinum, Cercospora arachidicola Hori, Botryosphaeria dothidea, Alternaria solani, Gibberella zeae and Phytophthora capsici at 50 mg/L. In particular, compound 6e showed 61.5% and 92.3% inhibition rate against Cercospora arachidicola Hori and Botryosphaeria dothidea, which was superior to the commercial positive control Chlorothalonil. These results will provide a potential clue for exploring novel high-effective agrochemicals.
A new method for the synthesis of functional enamines from β,β-dicyanostyrene derivatives and N-bromosaccharin(NBSA) was developed. In the presence of Na2CO3, the the reaction of β,β-dicyanostyrene derivatives with NBSA can generate the corresponding enamines smoothly in a mixed solvent of dichloromethane and N,N-dimethylformamide(DMF)(volume ratio 1:1) at 50 °C. The reaction of 14 kinds of β,β-dicyanostyrene derivatives with NBSA was investigated. Screened olefins afforded the corresponding enamines in good to excellent yields(up to 94%), indicating that the method has a wide adaptability for the substrate. The catalyst used is inexpensive and stable for storage. The amino groups of all products in their structures are on the α-position of products, revealing the reaction has an excellent regioselectivity. The possible pathway involving aminobromination of β,β-dicyanostyrene derivative with NBSA first and then elimination of HBr process in one pot has been proposed. The structures of all products were confirmed by 1H NMR, 13C NMR and HRMS analysis.
The bioluminescent mechanism of colenterazine dioxetanone(CZD) in the photoprotein of Obelia(obelin) was investigated by the combined quantum and molecular mechanics(QM/MM) method at TD-DFT level, which involved the real protein environment in decomposition of 1,2-dioxetanones. The anionic decomposition of CZD in (CZD+H2O)– model can go through a charge transfer(CT) catalyzed asynchronous-concerted process, which can be elucidated by the gradual reversible CT initiated luminescence(GRCTIL) mechanism. The neutral CZD in (CZDH+H2O) decomposes through an uncatalyzed non-CT biradical process. The anionic decomposition catalyzed by CT, in which the S0/S1 surface “double crossing” hence has ability to provide high quantum yield of singlet chemiexcitation is thus more possible in bioluminescence of photoprotein.
Based on spiro[fluorene-9,90-xanthene](SFX, dye 1), the Lindqvist-type polyoxometalate(POM) functio-nalized with SFX and its derivatives(dyes 2―4) used in dye-sensitized solar cells(DSSCs) were designed and inves-tigated with the density functional theory(DFT) and time-dependent DFT(TD-DFT) calculations. The results indicate that Lindqvist-type POM is the main contribution to the lowest unoccupied molecular orbital(LUMO) and affects the LUMO energies of dyes 2―4. The maximum absorptions of the designed dyes containing POM(dyes 2―4) are red shifted comparing with that of dye 1. The introduction of electron-donating group onto SFX segment is helpful to red shift the absorption spectra. The major factors affecting the performance of DSSCs, including light harvesting and electron injection were evaluated. Considering the absorption spectra and photovoltaic parameters, dyes 3 and 4 are promising high performance dye sensitizers in n-type DSSCs.
Direct evidence of effects of surface plasmon resonance(SPR) of gold nanorods(GNRs) on dual-band light absorption enhancement with coupling dye molecules was reported by introducing gold nanorod@SiO2(GNR@SiO2) core-shell nanoparticles into a photoelectric conversion system. GNR with asymmetric shape had unusual anisotropic SPR[transversal surface plasmon resonance(TSPR) and longitudinal surface plasmon resonance(LSPR)]. The excel-lent SPR of GNR made it a promising candidate as enhancing light absorption material to increase power conversion efficiency(PCE). The PCE was improved nearly 17.2% upon incorporating GNRs, mostly due to the increase in J sc, while V oc and FF were unchanged. The improvement was mostly contributed by the SPR of the GNRs with coupling of N719. And there was also a complementary to N719 in visible light range. Therefore, SPR is an effective tool in improving the photocurrent and consequently enhancement of PCE. The TSPR and LSPR effects of GNRs on light harvesting were reflected in the increased monochromatic incident photon-to-electron conversion efficiency(IPCE). We also utilized finite-difference time-domain(FDTD) to investigate the light coupling of GNRs with TiO2. Compare to the base anode, the IPCE of optimized electrode showed significant improvement and peaks broadening at 500–600 nm and 610–710 nm. We got an increase in overall conversion efficiency from 6.4% to 7.5%.
A well-known deep-blue emitting iridium(III) complex was selected for deuterium isotope effect evalua-tion, both on deuterated locations and numbers, through theoretical investigation. It was revealed that the containment of the d site deuteriation of ancillary ligand picolinate enabled the non-radiative deactivation process to be repessed, and thereby improving the quantum efficiency through such a simple and controllable approach.
Ab initio study of the reactions of n-heptyl radicals(1-C7H15, 2-C7H15, 3-C7H15, and 4-C7H15) with methanol was conducted over the temperature range of 300–1500 K. Transition states for the reaction channels producing C7H15OH, CH3, C7H15OCH3, H, C7H16, CH2OH and CH3O were identified and the geometries of all stationary points were calculated at BB1K/MG3S level of theory. The potential barrier heights of the corresponding transition states were predicted by the CBS-QB3//BB1K and G4//BB1K methods, indicating that the eight H-abstraction channels are more kinetically favorable than the channels where OH transfers from CH3OH to C7H15 and where the C7H15OCH3+H products are given. The rate constants of H-abstraction channels were calculated with TST and TST/Eck. Both the forward and reverse rate constants have positive temperature dependence and the tunneling effect is only important at the temperature lower than 700 K. For the reactions of H-atom abstraction from methyl in CH3OH by n-heptyl, a reverse and the corresponding forward rate constant are roughly equal. For the reactions of H-atom abstraction from OH in CH3OH by n-heptyl, a reverse rate constant is larger by several orders of magnitude than the corresponding forward one.
A new kind of inorganic composite adsorbent based on chitin whiskers(CHW) and potassium tetratitanate whiskers(PTW) was synthesized via the thermal deposition to remove Cu2+ and Pb2+ from wastewater. CHW could be successfully coated on the surface of PTW when thermal treated 8 times. The adsorption process was better fitted with the Langmuir and Freundlich models. The adsorption process was more conformed to the Pseudo-second-order model. The results from XPS(X-ray photoelectron spectrum) further show that the adsorption mechanism between CHW-PTW and Cu2+, Pb2+ are both ion exchange and chemical adsorption. Thermodynamic parameters suggest that the adsorption processes are nonspontaneous. The adsorption of Cu2+ and Pb2+ is endothermic and exothermic, respectively.
The metastable solubilities and the physicochemical properties including density and pH of the reciprocal quaternary system(LiCl+MgCl2+Li2SO4+MgSO4+H2O) at 348.15 K and 0.1 MPa were determined using the isother-mal evaporation method. The dry-salt diagram and water-phase diagram were plotted based on the experimental data. There are five invariant points, eleven univariant curves, and seven crystallization zones corresponding to hexahy-drite, tetrahydrite, kieserite, bischofite, lithium sulfate monohydrate, lithium chloride monohydrate and lithium car-nallite. Comparison between the stable and metastable diagrams at 348.15 K indicates that the metastable phenome-non of magnesium sulfate is obvious, and the crystallization regions of hexahydrite and tetrahydrite disappear in the stable phase diagram. A comparison of the metastable dry-salt phase diagrams at 308.15, 323.15 and 348.15 K shows that with the increasing of temperature the epsomite crystallization zone disappears from the dry-salt phase diagram of 303.15 K, and a new kieserite crystallization zone is presented at 348.15 K. The density and pH in the metastable equilibrium solution present regular change with the increasing of Jänecke index J(2Li+), and the calculated densities using the empirical equation agree well with the experimental values.
Solid-liquid phase equilibria of the two ternary systems (NaCl+SrCl2+H2O) and (KCl+SrCl2+H2O) at T=288.15 K and p=0.1 MPa were studied using the isothermal dissolution equilibrium method. Solubilities of the equilibrium liquid phase were determined, and the solids were also investigated by the Schreinemaker method of wet residues. In the ternary system (NaCl+SrCl2+H2O) at 288.15 K, there is one invariant point corresponding to (NaCl+SrCl2·6H2O) and two crystallization regions corresponding to NaCl and SrCl2·6H2O. The crystallized area of SrCl2·6H2O decreased with the increasing temperature, while that of NaCl increased slightly. In the ternary system (KCl+SrCl2+H2O) at 288.15 K, there is one invariant point(KCl+SrCl2·6H2O) and two crystallization regions cor-responding to KCl and SrCl2·6H2O. Both systems belong to a simple eutectic type, and neither double salts nor solid solutions were formed. On the basis of Pitzer-Harvie-Weare model, the solubilities of the two systems at 288.15 K were demonstrated. A comparison showed that the calculated solubilities agreed well with the experimental data.
An Ag-MnFe2O4-bentonite composite was synthesized by a chemical co-precipitation method and used for adsorption removal of Pb(II), Cd(II) and disinfection. The result of X-ray diffraction indicate that the diffraction peaks of MnFe2O4 and Ag can be perfectly indexed to the cubic spinel MnFe2O4(JCPDS No.88-1965) and metallic Ag(JCPDS No.41-1402), respectively. The results of scanning electron microscopy and energy dispersive X-ray spectroscopy manifest the deposition of MnFe2O4 and Ag on the bentonite surface and the presence of Mn, Fe and Ag. The result of X-ray photoelectron spectroscopy displayed that the composition of Ag-MnFe2O4-bentonite was Mn(II), Fe(III) and metallic Ag. The analysis of Brunauer-Emmett-Teller showed that the specific surface area of Ag-MnFe2O4-bentonite was the largest compared with that of bentonite, MnFe2O4 and MnFe2O4-bentonite. Thermo-dynamic studies revealed that the adsorption of Pb(II) and Cd(II) ions was spontaneous and endothermic. Langmuir model showed an adsorption capacity of 129.87 mg/g for Pb(II) and 48.31 mg/g for Cd(II) ions. The adsorption ki-netics of Pb(II) and Cd(II) ions onto Ag-MnFe2O4-bentonite can be best described by a pseudo-second-order model. The adsorption rate constant of the pseudo-second-order model was 0.0019 g·mg‒1·min‒1 for Pb(II) and 0.0065 g·mg‒1·min‒1 for Cd(II) ions. In addition to the adsorption experiment, the antibacterial properties of Ag-MnFe2O4-bentonite were studied through plate count method. Gram-negative(G‒) bacteria Escherichia coli and Gram-positive(G+) bacteria Lactobacillus plantarum were used to test the antibacterial properties. The results showed that the composite demonstrated excellent antibacterial activity. Thus, Ag-MnFe2O4-bentonite can be em-ployed as an adsorbent as well as an antimicrobial agent.
The correlation between inhibition efficiency and molecular structures of the inhibitor during hydrochloric acid corrosion of Q235 steel was studied by quantum chemical calculations and molecular dynamics(MD) simulation. The proton affinity(PA) calculations demonstrated that 2-(quinolin-2-yl)quinazolin-4(3H)-one inhibitor has the tendency to be protonated in hydrochloric acid, which was in good agreement with experimental observations. Besides, quantum chemical parameters revealed that the protonated corrosion inhibitor molecules were more easily adsorbed on Q235 steel surface and improved the corrosion resistance of steel. MD simulations were implemented to search for the adsorption behavior of this molecule on Fe (110) surface, which might be used as a convenient tool for estimating the interaction mechanism between inhibitor and iron surface.
The component solubilities, densities and refractive indices of the quaternary system Na+, Rb+, Mg2+//Cl–-H2O at 298.2 K were measured using an isothermal evaporation method. Based on the gathered data, a metastable phase diagram, a water content diagram, and a density/refractive index vs. composition diagram were constructed. The results show that this system is of a complex type with a double salt rubidium carnallite (RbCl·MgCl2·6H2O) formed at 298.2 K. Double salt rubidium carnallite, whose component point locates in its own crystallization zone in the dry salt phase diagram, belongs to congruent double salt at 298.2 K. Accompanied by the double salt that was formed, there are two invariant points in the phase diagram that cosaturated with three salts and an equilibrated solution. The cosaturated salts for the two invariant points are MgCl2·6H2O+RbCl·MgCl2·6H2O+ NaCl and NaCl+RbCl+RbCl·MgCl2·6H2O, respectively. Both invariant points are commensurate invariant points in the evaporation process, and the two invariant points are evaporative dry points. The sizes of the crystalline regions of the salts are in the order of NaCl>RbCl>RbCl·MgCl2·6H2O>MgCl2·6H2O.
Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly(tert-butyl acrylate) macromonomers functionalized with norbornenyl end group(NB-PtBA) were synthesized via atom transfer radical polymerization in three different molecular weights, 2000(NB-PtBA-2k), 3000(NB-PtBA-3k), and 8000(NB-PtBA-8k). Additionally, brush polymers with PtBA as side chains were synthesized via ring-opening metathesis polymerization(ROMP). Kinetic studies on ROMP of NB-PtBA showed that there was a ceiling degree of polymerization(CDP) for the brush polymers, beyond which the polymerization of NB-PtBA was out of control. For brush polymers of P[NB-PtBA-2k] and P[NB-PtBA-3k], CDPs were estimated to be ca. 400, but the value of P[NB-PtBA-8k] was ca. 100. Therefore, the controlled ROMP of brush polymers was critical at the CDP limit with increased macromonomer molecular weight.
Isotactic polypropylene(iPP) and graphene oxide(GO), dispersed in dibutyl phthalate(DBP) and dioctyl phthalate(DOP), were blended to prepare organic-inorganic-blended microfiltration membranes using thermally induced phase separation(TIPS). These membranes were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), contact angle measurements, mechanical properties, permeation tests, and porosity measurements. The morphology studied by SEM shows larger pores of the GO-blended membranes when compared to those of unmodified iPP membranes. Composite iPP/GO membranes achieve better performance in terms of water fluxes and pure water fluxes recovery ratio due to the hydrophilic nature of GO when compared with the pure iPP membranes. The addition of GO increases the permeability and the tensile strength by 352.98% and 123%, respectively, and also decreases the contact angle from 125° to 52.33°. We concluded that the composite membrane with 0.3% GO has the best antifouling ability of the membranes tested because it has the highest values of mean pore radius, porosity, and water flux observed in this study.
Based on a new biscarboxyl-functionalized Schiff base ligand 1,2-cyclohexanediamino-N,N′-bis[3-methoxyl-5-(p-carboxyl-phenylazo)] salicylidene(H4L), four polymers, [(CH3)2NH2]2·[Mn3(L)2(H2O)4]·2DMF(CP1), [Fe2(L)(H2O)(DMF)](CP2), [(CH3)2NH2]·[Cu(HL)]·H2O(CP3) and [Ni2(L)(teta)]·2DMF·H2O(CP4), have been synthesized(teta=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). In CP1, both of the internal [N2O2] pocket and the external carboxylate groups of L4– anion are ligated by Mn2+ ions, and the structure displays a layer. In CP2, the Fe2+ cations are linked by L4– anions to form a binuclear double chain. CP3 displays a [Cu2(HL)2] dimer. In CP4, the Ni2+ ions are connected by L4– anions to form a chain. The structures are further linked by hydrogen bonds to form 2D or 3D supramolecular architectures, respectively. CP1 exhibits adsorption ability to three organic dyes.
In recent years, there has been a considerable research interest in moving-bed biofilm reactor(MBBR) for its efficiency and stability. This work proposes a new way to modify the hydrophilicity of polyurethane foam(PU) carriers via the layer-by-layer self-assembly of hyperbranched polymeric diazonium salt(M-HB-DAS) and poly(sodium-p-styrenesulfonate)(PSS). Modified carriers showed very good adsorption for microbes according to the results of scanning electron microscope(SEM). Biochemical experiments on wastewater treatment confirm that the modified PU carriers can improve the removal rate of chemical oxygen demand(COD).
Linear bis-urea D230 series and branched tris-urea T403 series of supramolecular monomers were synthesized using low molecular weight polyetheramine D230, T403 and isocyanates with diverse functional groups. Rheological tests reveal that the materials possess special thermal and mechanical properties due to the strong hydrogen bonding interactions between terminal urea groups and the high flexibility of the polyetheramine middle segments. By enhancing the hydrogen bonding interactions through electronic effects of the substituted urea groups, the mechanical properties of the bulk material can be increased. Moreover, the branched T403 series with higher hydrogen bonding density also shows better performance against D230 series with the same substituted urea groups. The presence of π-π stacking between the phenyl groups in samples with phenylurea residues, which complements the hydrogen bonding, was also confirmed by fluorescence spectroscopy, therefore resulting in a stronger supramolecular polymer network.
In the quest for developing a catalyst with as many desired characteristics, a facile synthetic route was designed for the preparation of mesoporous silica coated magnetic nanoparticles(MSMNP) employing a colloid mill reactor. The composite particles were characterized by the techniques, such as nitrogen adsorption-desorption isotherms, scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction patterns (XRD), thermo-gravimetric analysis(TGA), Fourier transform infrared spectroscopy(FTIR) and vibrating sample magnetometer(VSM), etc. The analysis showed that the resulted MSMNP composites were composed of silica shell layers with open pores connecting channels and NiFe2O4 with spinel structure, so the thermal treatment temperature did not show significant effect on pore textural properties, and its specific surface areas were in the range of 443–474 m2/g, while pore volume of about 0.8 cm3/g with an average pore size of around 9.5 nm. The composites with super paramagnetic nature were encapsulated entirely with amorphous silica layers contributing to optimum porosity and abundant surface hydroxyl groups.
In this study, rigid 4,4′-diglycidyl(3,3′,5,5′-tetramethylbiphenyl) epoxy(TMBP)-based composites were developed by the incorporation of varying percentages of commercial hollow glass microspheres(HGMs, QH-450) into the TMBP resin used for electronic packaging. The thermal and mechanical properties as well as the morphology of all the composites were characterized, and dielectric properties were characterized by advanced analytical techniques. The results reveal that a series of TMBP/QH-450 composites exhibits higher initial degradation tempera-tures(T d,5%>300 °C), and the residual char and glass transition temperature were clearly improved with QH-450 loading. In addition, all epoxy composites exhibited a lower dielectric constant ranging from 3.74 to 3.06 at 1.2 MHz because the lower dielectric properties of the inert gas used as the core of the QH-450 decreased molecule polarity. Hence, this developed TMBP/QH450 system demonstrates potential applications in electronic packaging.