一些含三氮杂茂偶氮染料O,N供体的Zr(Ⅱ)配合物的合成、表征和抗微生物活性(英文)

合成了9种3-(2-羟基萘基-1-偶氮)-1,2,4-三氮唑(HL1),3-(2,4-二羟苯基-1-偶氮)-1,2,4-三氮唑(HL2),3-(2-羟基-3-羧基萘基-1-偶氮)-1,2,4-三氮唑(HL3),3-(2-羟基-5-溴苯基-1-偶氮)-1,2,4-三氮唑(HL4)和3-(2-羟基-5-甲基苯基-1-偶氮)-1,2,4-1,2,4-三氮唑(HL5)的Zr(Ⅱ)配合物并用元素分析,摩尔电导,磁矩,IR,UV-Vis,1H-NMR以及热分析(TGA和DTA)对其进行了表征。结果表明HL1-HL5以二齿一元配体方式通过偶氮的氮原子和羟基基团的氧原子与Zr(Ⅱ)离子配位生成单核配合物。用4种革兰氏阴性菌,即大肠杆菌(Escherichia coli),粘质沙雷氏菌(Serratia marcescens),阴沟肠杆菌(Enterobacter cloacae)和普通变形杆菌(Proteus vulgaris),以及2种真菌,即白色念珠菌(Candida albicans)和黑曲霉菌(Aspergillus niger)对配体及其配合物的生物学活性进行了研究。最小抑菌浓度(MICs)用纸上杯碟琼脂扩散法测定,结果表明在大多数情况下,金属化的配合物的抗微生物活性与自由配体相比有所增强。     

Investigation of 3-amino-1,2,4-triazole azodye derivatives as reagents for determination of mercury(II)

The reaction of mercury(II) with 3-(2,4-dihydroxyphen-1-ylazo)-1,2,4-triazole (HL¹), 3-(2-hydroxy-5-methylphen-1-ylazo)-1,2,4-triazole (HL²), 3-(2-hydroxy-5-ethoxycarbonylphen-1-ylazo)-1,2,4-triazole (HL³), 3-(2-hydroxy-5-acetylphen-1-ylazo)-1,2,4-triazole (HL⁴), 3-(2-hydroxy-5-formylphen-1-ylazo)-1,2,4-triazole (HL⁵), and 3-(2-hydroxy-5-bromophen-1-ylazo)-1,2,4-triazole (HL⁶) was studied. A new, direct, and simple procedure was suggested for the spectrophotometric determination of mercury(II) based on its complexation reaction with HL¹-HL⁶. The best reagent was found to be HL³ due to its high sensitivity and selectivity. In aqueous media of pH 9.0 containing 40 vol. % of methanol, Hg(II) reacts with HL³ to form a 1:2 (Hg(II) · HL³) complex having a sensitive absorption peak at 490 nm with the molar extinction coefficient of 3.31 × 10⁴ L mol⁻¹ cm⁻¹ using 4 × 10⁻⁴ M of the reagent. Beer’s law is obeyed over the range from 0.00 μg mL⁻¹ to 12.04 μg mL⁻¹ of mercury(II). The proposed method was applied in the determination of mercury(II) in tap water, seawater and synthetic seawater samples, without the need of prior treatment, with satisfactory results.     

The potential use of plume imaging for real-time monitoring of laser ablation cleaning of stonework

In this work, the potential of plume imaging was investigated as a real-time monitoring technique for the control of the laser cleaning process in cultural heritage objects with emphasis on encrusted stonework. Optical pulses generated by Nd:YAG laser were used to remove a high absorbing layer of crust from the surface of a lower absorbing marble substrate. Two regimes of operation have been employed for laser cleaning test, Q-switched ns mode, and short free running μs mode. Laser induced breakdown spectroscopy (LIBS) was also employed to study the stratigraphy of the cleaned surfaces, and thus to confirm the validity of the suggested monitoring technique. The tests proved the prospective of introducing plume imaging techniques as a straightforward and inexpensive tool for the real-time monitoring of laser ablation and the determination of the critical point for a safe surface cleaning intervention.     

Synthesis, molecular docking and preliminary in-vitro cytotoxic evaluation of some substituted tetrahydro-naphthalene (2',3',4',6'-tetra-O-acetyl-β-D-gluco/-galactopyranosyl) derivatives

A facile, convenient and high yielding synthesis of novel S-glycosides and N-glycosides incorporating 1,2,3,4-tetrahydronaphthalene and or 1,2-dihydropyridines moieties has been described. The aglycons 2, 4, and 7 were coupled with different activated halosugars in the presence of basic and acidic medium. The preliminary in-vitro cytotoxic evaluation revealed that compounds 3c, 3f, 5c and 7b show promising activity. A molecular docking study was performed against tyrosine kinase (TK) (PDB code: 1t46) by Autodock Vina. The docking output was analyzed and some compounds have shown hydrogen bond (H-B) formation with reasonable distances ranged from 2.06 A° to 3.06 A° with Thr 670 and Cys 673 residues found in the specified pocket. No hydrogen bond was observed with either Glu 640 nor Asp 810 residues, as was expected from pdbsum.     

Critical parameters of hard-core Yukawa fluids within the structural theory

A purely statistical mechanical approach is proposed to account for the liquid–vapor critical point based on the mean density approximation (MDA) of the direct correlation function. The application to hard-core Yukawa (HCY) fluids facilitates the use of the series mean spherical approximation (SMSA). The location of the critical parameters for HCY fluid with variable intermolecular range is accurately calculated. Good agreement is observed with computer simulation results and with the inverse temperature expansion (ITE) predictions. The influence of the potential range on the critical parameters is demonstrated and the universality of the critical compressibility ratio is discussed. The behavior of the isochoric and isobaric heat capacities along the equilibrium line and the near vicinity of the critical point is discussed in details.     

Pairwise weakly and pairwise strongly irresolute functions

In this paper we consider a new weak and strong forms of irresolute functions in bitopological spaces, namely, ij-quasi-irresolute functions and strongly irresolute functions. Several characterizations and basic properties of these functions are given. We investigate the relationships among some weak forms of continuity and other generalizations of continuous mappings in bitopological spaces.     

Intercalation of Toluidines into α-Zirconium Hydrogenphosphate

Intercalates of o-, m-, and p-toluidine into α-Zr(HPO₄)₂ · H₂O were prepared and characterized by powder X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. As follows from IR, toludine molecules are protonated in the interlayer space. Toluidine molecules are arranged in a bimolecular way in the intercalates containing more than 1.5 toluidine molecules per Zr atom. On the other hand, a monolayer of the toluidine molecules is supposed in the intercalates with less than one toluidine molecule per Zr atom.     

UV-vis, IR and (1)H NMR spectroscopic studies of some Schiff bases derivatives of 4-aminoantipyrine

Five Schiff bases derived from 4-aminoantipyrine and benzaldehyde derivatives (I) are prepared and their UV-vis, IR, (1)H NMR and fluorescence spectra are investigated and discussed. The electronic absorption spectra of the hydroxy 4-aminoantipyrine Schiff bases Ib and Ie as well as the fluorescence spectra of Ie are studied in the organic solvents of different polarity. The UV-vis absorption spectra of 4-aminoantipyrine Schiff bases Ib, Id and Ie are investigated in aqueous buffer solutions of varying pH and utilized for the determination of pK(a) and DeltaG of the ionization process. The reactions of the hydroxy compounds Ib and Ie with Ni(II) and Cu(II) ions are also studied. The results of spectral studies are supported by some molecular orbital calculations using an atom superposition and electron delocalization molecular orbital theory for a compound Ib.