Qing-Fu Zeng

Synthesis, molecular docking and biological evaluation of Schiff base transition metal complexes as potential urease inhibitors

Six transition metal compounds of Schiff base ligands were evaluated for the inhibitory activity on jack bean urease, of which compounds 2-6 were determined by single crystal X-ray analysis. It was found that copper(II) complexes 1 and 4 showed strong inhibitory activity against jack bean urease (IC(50) = 0.52 and 0.46 microM), compared with acetohydroxamic acid (IC(50) = 42.12 microM) as a positive reference. Cobalt(II), nickel(II) and zinc(II) compounds also exhibited potent inhibitory activity (IC(50) = 3.88-25.20 microM). A docking analysis using the AUTODOCK 4.0 program could explain the inhibitory activities of 1 and 4 against urease.

Synthesis and antimicrobical evaluation of a novel class of 1,3,4-thiadiazole: Derivatives bearing 1,2,4-triazolo[1,5-a]pyrimidine moiety

A series of novel 1,3,4-thiadiazole derivatives bearing 1,2,4-triazolo[1,5-a]pyrimidine moiety were synthesized by the method of splicing active substructures. Among these derivatives, compounds 12, 13, 15-22 and 24-31 were firstly reported. All the compounds were assayed for antimicrobial activities against five fungi strains and four bacteria strains. The preliminary results indicated that compounds 25 and 28-31 showed good antifungal activities against Physaclospora piricola and Rhizoctonia solani. Compound 26 exhibited good antifungal activities against Cercospora beticola and R. solani. Most of the compounds showed better antibacterial activities against Gram-negative bacteria strains than Gram-positive bacteria strains. Compounds 25 and 28 showed the best activities against Pseudomonas fluorescence while compounds 30-31 showed good activities against Escherichia coli.

Treatment of simulated wastewater containing Reactive Red 195 by zero-valent iron/activated carbon combined with microwave discharge electrodeless lamp/sodium hypochlorite.

A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon (ZVI/AC), microwave discharge electrodeless lamp/sodium hypochlorite (MDEL/NaClO) and the combination of ZVI/AC-MDEL/NaClO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaClO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaClO, we found that in the ZVI/AC-MEDL/NaClO process, ZVI/AC could break the azo bond firstly and then MEDL/NaClO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.

Removal of a Toxic Anthraquinone Dye by Combination of Red Mud Coagulation and Ozonation

Removal of a toxic anthraquinone dye—Disperse Blue 56 (DB56) by single red mud (RM) coagulation, single ozonation and combined RM coagulation/ozonation (RM/O3) was carried out in laboratory-scale experiments. RM/O3 treatment exhibited more effective in toxicity removal, color removal and chemical oxygen demand (COD) reduction than the other two methods. The effect of several operational parameters, including initial dye concentration, pH value, RM coagulant dose and O3 dose, on color removal and COD reduction was also investigated. Among these factors, pH value had the most important effect.

Photoreduction of Reactive Brilliant Red X-3B by Ultraviolet Irradiation/Potassium Borohydride/Sodium Bisulfite

Photoreduction of Reactive Brilliant Red X-3B in aqueous solution by ultraviolet irradiation/potassium borohydride/sodium bisulfite (UV/KBH 4 /NaHSO 3 ) was investigated. The effects of operational parameters including KBH 4 dosage, NaHSO 3 dosage, pH value, and temperature were studied. The reaction mechanism was also discussed. The preliminary results showed that UV and KBH 4 /NaHSO 3 had a significant synergy for the decolorization. At the conditions of 6-mg KBH 4 , 250-mg NaHSO 3 , pH 6.0, and room temperature, highest color removal percentage was achieved. From the mechanism discussion, we could conjecture that the mechanism of photoreduction was mainly caused by the production of sulfur dioxide anion radicals, and UV irradiation played a vital role during the process.

Degradation of Active Brilliant Red X-3B by a microwave discharge electrodeless lamp in the presence of activated carbon.

Degradation of Active Brilliant Red X‐3B (X‐3B) in aqueous solution by a microwave discharge electrodeless lamp (MDEL) in the presence of activated carbon was investigated. The preliminary results proved this method could effectively degrade X‐3B in aqueous solution. The removal percentages of colour and chemical oxygen demand were up to approximately 99% and 66%, respectively, at the conditions of 0.8 g/L dye concentration, 20 g/L activated carbon, pH 7.0 and 8 min microwave irradiation time. The degradation basically belonged to first‐order reaction kinetics and its rate constant was 0.42 min−1. No aromatic organics were detected in the final treated solution, indicating that the mineralization was relatively complete. By studying the change in solution properties, it could be concluded that MDEL‐assisted oxidation was the dominant reaction mechanism. In addition, the influence of operational parameters and reuse of activated carbon were also discussed.

Bis[(E)-4-chloro-2-(2-furylmethyl­imino­meth­yl)phenolato]iron(II)

The Fe atom of the title compound, [Fe(C12H9ClNO2)2], lies on a crystallographic twofold rotation axis. The FeII atom is four-coordinated in a tetrahedral geometry by the O and N atoms of the two Schiff base ligands. The O atom of the furan substituent in the ligand unit is not involved in coordination to the Fe atom.

Bis[(E)-4-chloro-2-(cyclo-hexyl-imino-meth-yl)phenolato]nickel(II).

In the title mononuclear nickel(II) complex, [Ni(C13H15ClNO)2], the NiII atom is four-coordinated in a tetrahedral geometry by the N and O atoms of the two Schiff base ligands.

Identification and phylogenetic analysis of new sulfate-reducing bacteria isolated from oilfield samples.

Microbiologically influenced corrosion (MIC) caused by sulfate-reducing bacteria (SRB) has been investigated in an oilfield injection water system. Strain CW-01 was isolated from an oilfield and strain CW-04 was isolated from biofilm dirt of pipeline walls. The strains were facultative anaerobes, non-motile, Gram-positive, pole flagellum, and spore-forming curved rods. The growth was observed over the temperature range 20-70 °C. Strain CW-01 grew optimally at 37 °C. The pH range for growth was 3.0-11, optimal at pH 6.0. Strain CW-04 grew optimally at 48 °C. The pH range for growth was 3.0-10, optimal at pH 7.2. The strains grew at a very broad range of salt concentrations. Optimal growth was observed with 1.5 g/L NaCl for strain CW-01 and 0.7 g/L NaCl for strain CW-04. The strains showed most similarity in physiological characteristics, except for acetone and saccharose. Analysis of the 16S rDNA sequences allowed strains CW-01 and CW-04 to be classified into the genus Desulfotomaculum. The corrosion speciality of the strains had been comparatively investigated. Especially SRB’s growth curve, bearable oxygen capability, drug fastness and corrosion rate had been analyzed. The results showed that it is difficult to prevent bacterial corrosion caused by these two strains.

Di-μ-chlorido-bis­{chlorido[2-(2-furyl­methyl­imino­meth­yl)pyridine-κ2 N,N′]nickel(II)}

The title dinuclear nickel(II) complex, [Ni2Cl4(C11H10N2O)2], lies on a centre of symmetry located at the centroid of the four-membered ring formed by the two Ni atoms and the bridging chloride ions. The NiII atom is five-coordinated in a square-pyramidal geometry by the imine and pyridine N atoms of the Schiff base ligand, and by one terminal and two bridging Cl atoms. The Ni⋯Ni distance is 3.506 (2) Å. The O atom of the furan substituent in the ligand unit is not involved in coordination to the Ni atom.