Synthesis, characterization and antimicrobial property in vitro of supramolecular coordination polymers bearing brominated Schiff base ligand.

In this study, two supramolecular coordination polymers of Co(II) and Zn(II) based on brominated Schiff base (E)-4-bromo-2-((quinolin-6-ylimino)methyl)phenol (HL) were synthesized and characterized by using elemental analysis, IR spectroscopy and NMR spectroscopy. Furthermore, the crystal structures of HL, CoL2 (І) and ZnL2 (II) were determined by single crystal X-ray analysis. It was revealed that the bromine-related interaction played important role in the self-assembly of HL supramolecular network. The crystal structural investigations revealed that І and II were isomorphous with the same geometry around the metal atom and similar structural feature. The stable four-membered chelate structure resulted from coordination between the metal(II) ion and deprotonated bidentate ligand. And supramolecular coordination polymers of І and II formed diverse architecture through multiple hydrogen bondings, π···π interactions and halogen-related interactions. Antimicrobial activities of polymers were tested toward four bacteria and five phytopathogenic fungi. І and II showed higher activities toward the tested microorganisms than HL. Furthermore, the photoluminescence results indicated that HL and II accompanied with better fluorescence properties in the ultraviolet region.

CdS and Ag synergistically improved the performance of g-C3N4 on visible-light photocatalytic degradation of pollution.

CdS-AgO@g-C3N4 nanocomposites were successfully synthesized and characterized by XRD, N2 physical adsorption, XPS, SEM, TEM, EDX, and UV-Vis DRS (various technical means). The adsorption light range of as-prepared materials could extend to the whole visible light region with the addition of Ag. Silver can act as a bridge to facilitate the separation of electrons and holes, thereby greatly enhancing the photocatalytic activity of CdS-AgO@g-C3N4, enabling the maximum degradation efficiency of salicylic acid in water to reach 92.8% under visible light. Peroxy radical is the most important radical in the photocatalytic reaction process, followed by electron and hole, while hydroxyl radical has almost no effect. In addition, the mechanism of photocatalytic process was also explored.

Effect of biochar on immobilization remediation of Cd⁃contaminated soil and environmental quality.

PURPOSE: Field experiments were conducted to explore the remediation effects of ordinary biochar and PEI-modified biochar on the Cd-contaminated yellow brown soil, and the improvement of soil environment quality in southern Shaanxi province, so as to provide theoretical basis and technical support for in-situ remediation of Cd-contaminated soil in southern Shaanxi province. RESULTS AND DISCUSSION: Biochar applied in soil could increase the soil pH value, EC, ECEC, and SOC, and improve the soil physical and chemical properties to a certain extent. Biochar in soil could change the chemical form of Cd in soil, effectively passivate Cd in soil and reduce its bio-availability. Biochar could enhance the activities of catalase, urease, alkaline phosphatase and sucrase in soil to different degrees, and the four soil enzymes could be used as indicators of passivation effects of soil Cd by biochar. With biochar treatment, soil aggregates MWD and GMD increased to different degrees, so biochar could enhance soil stability. The biochar could decrease the content of Cd in different parts of wheat, the content of Cd in wheat grains had a highly significant positive correlation with the available content of Cd in soil, and highly significant or significant negative correlations with pH, SOC, EC, ECEC, and the activities of phosphatase, urease and sucrase in soil. Compared with ordinary biochar, the passivation effect of PEI-modified biochar on Cd was more significant. CONLUSIONS: The results of the study indicated that ordinary biochar and PEI-modified biochar could passivate the Cd in soil, and remediate Cd-contaminated soil, and improve the soil environmental quality effectively, compared with ordinary biochar, the PEI-modified biochar produced batter.

Effects of heavy metals on microorganisms and enzymes in soils of lead-zinc tailing ponds.

Taking the soil around the lead-zinc tailings pound in the upper reaches of the Hanjiang River in Shaanxi Province as the research object, with tailings pond as the center, seven different belt zones were divided outwards, the contents of Pb, Cu, Zn, V, Ni, Cd in soil were analyzed, as well as soil basic respiration (SBR), microbial biomass carbon (MBC), microbial metabolic quotient (MMQ), and the activities of catalase, urease, cellulase, invertase and neutral phosphatase were also determined. The purpose was to reveal the intrinsic relationship between soil microbial, enzyme activities and heavy metal pollution, and to establish the characterization system of enzyme activities, soil heavy metal pollution degree, as well as microbial parameters. The results showed that: (1) The potential ecological risk index of six heavy metals was ranked as Cd > Cu > Pb > Ni > Zn > V. Cd was a high potential ecological risk, Cu was a medium potential ecological risk, and Zn, Pb, V and Ni were low potential ecological risk. The comprehensive evaluation result of Hakanson's potential ecological hazard index showed that, Zone I was of high potential risk level, Zone II, III and IV were of medium risk level, and Zone V, VI and VII were of low level. (2) Microbial biomass carbon (MBC) had a significant negative correlation or extremely significant negative correlation with 6 heavy metals, and microbial metabolic quotient (MMQ) had a significant positive correlation or extremely significant positive correlation with 6 heavy metals. MBC and MMQ were effective microbiological indexes to measure the quality status of soil, while SBR was not. (3) Catalase, cellulase, sucrase and neutral phosphatase activity had significant negative correlation with the contents of 6 heavy metals, and they could replicate the pollution degree of substantial metals in the soil. However, urease had no significant correlation with the contents of 6 heavy metals, which could not reflect the pollution degree of soil heavy metals.

Strong acid-assisted preparation of green-emissive carbon dots for fluorometric imaging of pH variation in living cells.

New green-emissive carbon dots (G-CDs) are described here and shown to be viable fluorescent nanoprobes for the detection of changes in cellular pH values. By using m-phenylenediamine as the carbon source, G-CDs with an absolute quantum yield of 36% were solvothermally synthesized in the presence of strong H2SO4. The G-CDs have an average size of 2.3 nm and display strong fluorescence with excitation/emission peaks at 450/510 nm. The fluorescence intensity depends on the pH value in the range from 6.0 to 10.0, affording the capability for sensitive detection of intracellular pH variation. The nanosensor with excellent photostability exhibited good fluorescence reversibility in different pH solutions, and showed excellent stability against the influence of other biological species. The nanoprobe was successfully used in confocal fluorescence microscopy to determine pH values in SMMC-7721 cells. Graphical abstract Schematic presentation of green-emissive carbon dots (G-CDs) synthesized using m-phenylenediamine and sufuric acid through a solvothermal method for real-time fluorometric monitoring of intracellular pH values. Mechanism can be ascribed to PET process from the electron lone pair in amino group to the CDs.

A novel thermometer-type hydrogel senor for glutathione detection.

A thermometer-type visual sensor for glutathione (GSH) sensing was developed with stimulus-responsive fluorescent hydrogel which was obtained by using 5, 6-bicarboxylic fluorescein crossli`nked partly ammoniated polyacrylamide. Various experimental parameters such as the particle size of hydrogel, buffer solution and swelling time were optimized. It is accessible to measure the volume change of hydrogel with the sensor by reading the graduation on a pipette like thermometer with naked eye. The concentration of the GSH depended on the volume in a certain range as the signal. Satisfactory agreements between the sensor and HPLC results for atuomolan tablet assays indicated the capability of the thermometer-type sensors for the analysis of real samples. These findings proved the utility of stimulus-responsive, intelligent hydrogel and the suitability of thermometer-style visual sensor design for quantitative assays.

Changing molecular conjugation with a phenazine acceptor for improvement of small molecule-based organic electronic memory performance.

Two conjugated small molecules with different molecular conjugation, 4',4''-(diazene-1,2-diyl)bis(2',3',5',6'-tetrafluoro-N,N-diphenyl-[1,1'-biphenyl]-4-amine) (TPA-azo-TPA) and 4,4'-(perfluorophenazine-2,7-diyl)bis(N,N-diphenylaniline) (TPA-ph-TPA), in which the electron donor triphenylamine moiety is bridged using different electron-accepting azobenzene or phenazine blocks, were designed and synthesized. The TPA-ph-TPA molecule with a larger conjugation acceptor regularly formed a nanocrystalline film and the as-fabricated memory devices exhibited outstanding non-volatile write once read many (WORM) memory effects with an ON/OFF ratio ten times higher than that of TPA-azo-TPA. Using theoretical calculations, it was speculated that the memory performance is a result of an electric field induced charge transfer effect and the enhanced device performance of the acceptor molecular conjugation is because of the presence of a strong charge transfer effect. The experimental findings suggest that the strategy of molecular conjugation may promote the performance of small molecule-based organic electronic memory devices by an enhanced a strong charge transfer effect.

Theoretical investigation on exciton-dissociation and charge-recombination processes of PC61BM-PTDPPSe interface.

Designing and synthesizing novel electron-donor polymers with the high photovoltaic performances has remained a major challenge and hot issue in organic electronics. In this work, the exciton-dissociation (k dis ) and charge-recombination (k rec ) rates for the PC61BM-PTDPPSe system as a promising polymer-based solar cell candidate have been theoretically investigated by means of density functional theory (DFT) calculations coupled with the non-adiabatic Marcus charge transfer model. Moreover, a series of regression analysis has been carried out to explore the rational structure-property relationship. Results reveal that the PC61BM-PTDPPSe system possesses the large open-circuit voltage (0.77 V), middle-sized exiton binding energy (0.457 eV), and relatively small reorganization energies in exciton-dissociation (0.273 eV) and charge-recombination (0.530 eV) processes. With the Marcus model, the k dis , k rec , and the radiative decay rate (k s ), are estimated to be 3.167×10(11) s(-1), 3.767×10(10) s(-1), and 7.930×10(8) s(-1) respectively in the PC61BM-PTDPPSe interface. Comparably, the k dis is as 1∼3 orders of magnitude larger than the k rec and the k s , which indicates a fast and efficient photoinduced exciton-dissociation process in the PC61BM-PTDPPSe interface. Graphical Abstract PTDPPSe is predicted to be a promising electron donor polymer, and the PC61BM-PTDPPSe system is worthy of further device research by experiments.

Mechanistic and conformational studies on the interaction of sulfamethazine with human immunoglobulin G by molecular modeling and multi-spectroscopic approach in vitro.

Binding interaction of sulfamethazine (SMZ) with human immunoglobulin G (HIgG) has been explored under physiological conditions. The interaction mechanism was firstly predicted through molecular modeling which showed that several hydrogen bonds participated in stabilizing the SMZ-HIgG complex. Fluorescence spectroscopy, ultraviolet-visible (UV-vis) light absorption and circular dichroism (CD) spectroscopy were used to analyze the binding site, binding constants and effects of SMZ on HIgG stability and secondary structure. The binding parameters and thermodynamic parameters at different temperatures for the reaction have been calculated according to the Scatchard, Sips and Van 't Hoff equations, respectively. Experimental results showed that the quenching mechanism was a static quenching and there was one independent class of binding site on HIgG for SMZ during their interaction. The thermodynamic parameters of the reaction, namely standard enthalpy ΔH(0) and entropy ΔS(0), had been calculated to be -19.12 kJ · mol(-1) and 20.22 J · mol(-1) · K(-1), respectively, which meant that the electrostatic interaction was the predominant intermolecular force in stabilizing the SMZ - HIgG complex. Moreover, the conformational changes of HIgG in the presence of SMZ were confirmed by three-dimensional fluorescence spectroscopy, UV-vis absorption spectroscopy and CD spectroscopy.

Theoretical investigation on the crystal structures and electron transport properties of several nitrogen-rich pentacene derivatives.

Exploring and synthesizing new simple n-channel organic semiconductor materials with large electron mobility and high air stability have remained a major challenge and hot issue in the field of organic electronics. In the current work, the electron transport properties of four novel nitrogen-rich pentacene derivatives (PBD1, PBD2, PBD3, and PBD4) with two cyano groups as potential n-channel OFET materials have been investigated at the molecular and crystal levels by means of density functional theory (DFT) calculations coupled with the prediction of crystal structures and the incoherent charge-hopping model. Calculations reveal that the studied compounds, which possess low-lying frontier molecular energy levels, large ionization potentials and electron affinities, are very stable exposed to air. Based on predicted crystal structures, the average electron mobility at room temperature (T = 300 K) for PBD1, PBD2, PBD3, and PBD4 is predicted to be as high as 0.950, 0.558, 0.518, and 1.052 cm²·V⁻¹·s⁻¹, which indicate that these four compounds are more than likely to be promising candidates as n-type OFET materials under favorable device conditions. However, this claim needs experimental verification. In addition, the angular-dependent simulation for electron mobility shows that the electron transport is remarkably anisotropic in these molecular crystals and the maximum µ(e) appears along the crystal axis direction since molecules along this direction exhibit the close face-to-face stacking arrangement with short interplanar distances (~3.6-4.0 Å), which induces large electronic couplings.

N'-(5-Bromo-2-hydr-oxy-3-methoxy-benzyl-idene)-4-hydr-oxy-3-methoxy-benzohydrazide dihydrate.

In the title compound, C(16)H(15)BrN(2)O(5)·2H(2)O, the dihedral angle between the two aromatic rings is 2.9 (2)° and an intra-molecular O-H⋯N hydrogen bond is observed. One of the water mol-ecule is disordered over two positions, with occupancies of 0.83 (3) and 0.17 (3). In the crystal structure, mol-ecules are linked into a three-dimensional network by inter-molecular O-H⋯O, O-H⋯(O,O), O-H⋯N and N-H⋯O hydrogen bonds. π-π inter-actions involving Br-substituted benzene rings, with a centroid-centroid distance of 3.552 (3) Šare also observed.

N'-(4-Hydr-oxy-3-methoxy-benzyl-idene)-4-methoxy-benzohydrazide monohydrate.

In the title compound, C(16)H(16)N(2)O(4)·H(2)O, the dihedral angle between the two aromatic rings is 19.6 (2)°. In the crystal structure, mol-ecules are linked into a three-dimensional network by inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds.

N'-(3-Eth-oxy-2-hydroxy-benzyl-idene)-4-hydr-oxy-3-methoxy-benzohydrazide monohydrate.

In the title compound, C(17)H(18)N(2)O(5)·H(2)O, the dihedral angle between the two aromatic rings is 7.86 (7)° and an intra-molecular O-H⋯N hydrogen bond is observed. In the crystal structure, mol-ecules are linked into a three-dimensional network by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds.

[Study on the determination Cu, Cr, Al, Ni and Ti in corrosion solution of oxidation equipment in supercritical water by ICP].

The Cu, Cr, Al, Ni and Ti in corrosion solution of oxidation equipment in supercritical water by inductively coupled plasma-atomic emission spectrometry has been investigated, the authors used catalysts (CuO/Al2O3) to oxidize unsymmetrical dimetylhydrazine in supercritical water in a stainless steel (1Cr18Ni9Ti) reactor. The test was operated under condition of 400-500 degrees C and 24-26 MPa. The results indicate that the dissolution of Cr in stainless steel were occurred in supercritical water and dissolution became severe with higher temperature and pressure.