Synthesis,characterization, electrochemical behaviour and X-ray crystal structures of nickel(II) complexes with a N2O4 donor set macrocyclic Schiff base ligand

Two nickel(II) complexes of [1 + 1] macrocyclic Schiff base ligand (L) have been prepared by cyclocondensation reactions between 1,3-diamino-2-propanol and 2-[3-(2-formylphenoxy)-2-hydroxypropoxy] benzaldehyde, using NiX₂ (X = Br, and I) salts as template agents, and characterized by elemental analyses, IR, molar conductivity and electronic spectra in both solid and solution states. The single-crystal X-ray diffractions of the complexes are also reported that contain nickel(II) ion in a distorted octahedral geometry coordination of N₂O₃X (X = Br, I and NO₃). In all complexes the ligand behaves as a pentadentate ligand. Cyclic voltammetric studies of nickel(II) complexes indicate a quasi-reversible redox wave in the negative potential range.     

Enantioselective addition of diethylzinc to aryl aldehydes catalyzed by novel chiral imino alcohol ligands

The enantioselective alkylation of aryl aldehydes by diethylzinc in the presence of catalytic amounts of several novel chiral imino alcohol ligands, synthesized from the reaction of (R)-2-amino-1-butanol with aromatic aldehydes, was studied. The influence of temperature and ligand structure was investigated and enantioselectivity up to 81% was obtained.     

One-pot synthesis of 1,2,3-triazole linked dihydropyrimidinones via Huisgen 1,3-dipolar/Biginelli cycloaddition

The combination of the Biginelli reaction with click chemistry has been used for the one-pot synthesis of 1,2,3-triazole linked dihydropyrimidinones from azides, aromatic aldehydes containing a propargyl ether group, urea, and 1,3-dicarbonyl compounds using Cu(OAc)₂/sodium ascorbate as catalyst in acetic acid under mild reaction conditions.     

The X<Superscript>−</Superscript>···benzohydrazide complexes: the interplay between anion-π and H-bond interactions

The compounds containing the benzohydrazide (BH) nucleus have a variety of biological activities because of various noncovalent intermolecular interactions. The interplay between anion-π and H-bond interactions, which can affect the activity of compounds, has been investigated in ten substituted BH exposed to the chloride ion using the quantum mechanical calculations. The total interaction energy is separated into the anion-π (ΔE _Aπ) and H-bond (ΔE _HB) contributions where both interactions are presented in the complexes. The electron-withdrawing substituents (EWSs) increase |ΔE _Aπ| and decrease |ΔE _HB|, while reversed changes are observed with the electron-donating substituents (EDSs). In addition, the total binding energy (ΔE) becomes more/less negative in the presence of EWSs/EDSs. The synergetic effects of mentioned interactions and substituent effects have also been investigated using the atoms in molecules (AIM), natural bond orbital (NBO) and molecular electrostatic potential (MEP) analyses. A good correlation is found between the energy data and the Hammett constants, the minimum of electrostatic potential (V _min) and the results of population analyses.     

A meshless point collocation method for 2-D multi-term time fractional diffusion-wave equation

In this paper, a meshless collocation method is considered to solve the multi-term time fractional diffusion-wave equation in two dimensions. The moving least squares reproducing kernel particle approximation is employed to construct the shape functions for spatial approximation. Also, the Caputo’s time fractional derivatives are approximated by a scheme of order O(τ ^3?α ), 1< α < 2. Stability and convergence of the proposed scheme are discussed. Some numerical examples are given to confirm the efficiency and reliability of the proposed method.     

Strictly feasible solutions and strict complementarity in multiple objective linear optimization

Recently, Luc defined a dual program for a multiple objective linear program. The dual problem is also a multiple objective linear problem and the weak duality and strong duality theorems for these primal and dual problems have been established. Here, we use these results to prove some relationships between multiple objective linear primal and dual problems. We extend the available results on single objective linear primal and dual problems to multiple objective linear primal and dual problems. Complementary slackness conditions for efficient solutions, and conditions for the existence of weakly efficient solution sets and existence of strictly primal and dual feasible points are established. We show that primal-dual (weakly) efficient solutions satisfying strictly complementary conditions exist. Furthermore, we consider Isermann’s and Kolumban’s dual problems and establish conditions for the existence of strictly primal and dual feasible points. We show the existence of primal-dual feasible points satisfying strictly complementary conditions for Isermann’s dual problem. Also, we give an alternative proof to establish necessary conditions for weakly efficient solutions of multiple objective programs, assuming the Kuhn–Tucker (KT) constraint qualification. We also provide a new condition to ensure the KT constraint qualification.     

Adsorption of Metanil Yellow Azoic Dye from Aqueous Solution onto Mg‐Fe‐NO3 Layered Double Hydroxide

We report the preparation and characterization of a layered double hydroxide (LDH) adsorbent for azoic dye, metanil yellow (yellow GX; YGX) removal. The nanoparticles of Mg‐Fe‐LDH‐NO₃ adsorbent were prepared with Mg/Fe molar ratio of 3:1 by a hydrothermal process and coprecipitation method at pH 9.5 and were characterized by X‐ray powder diffraction (XRPD), thermal gravimetric analysis (TGA), elemental analysis, and Fourier transform infrared spectroscopy (FT‐IR). The size and morphology of nanoparticles were examined by scanning electron microscopy (SEM). The XRD patterns indicate that the intercalation of YGX between the LDH layers has not occurred and surface adsorption has happened. In the adsorption experiments, the Gibbs free energy ΔG⁰ values, the enthalpy ΔH⁰, and entropy ΔS⁰ was determined. The isotherms showed that the adsorption of YGX by Mg‐Fe‐LDH‐NO₃ was both consistent with Langmuir and Freundlich equations.     

Thermal Decomposition Kinetics of Ethane Halides and Derivatives（C_2H_（6-n）X_n（n = 1～3）;X = F,Cl,Br）：DFT Study and NBO Analysis

A theoretical study of the thermal decomposition kinetics of ethane halides(C2H6-nXn(n = 1～3);X = F,Cl,Br) has been carried out at the B3LYP/6-31++G** and B3PW91/631++G** levels of theory.Among these methods and comparison of activation parameters with available experimental values,the B3PW91/6-31++G** method is in good agreement with the experimental data.The analysis of bond order and natural bond orbital(NBO) charges,bond indexes,and synchronicity parameters suggest the elimination of HX in reactions 1～9(HF:compounds 1～3,HCl:compounds 4～6,and HBr:compounds 7～9) occur through a concerted and slightly asynchronous four-membered cyclic transition state type of mechanism.     

An Efficient One‐Pot,Four‐Component Synthesis of {[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione Derivatives

The 1‐{[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione derivatives 5 were synthesized by a simple and efficient method, i.e., by the four‐component, one‐pot condensation reaction of phthalohydrazide 4 , a (propargyloxy)benzaldehyde 1 , an active methylene compound 3 (malononitrile or ethyl cyanoacetate), and an azide 2 in the presence of Cu(OAc)₂/sodium L ‐ascorbate as catalyst and 1‐methyl‐1H‐imidazolium trifluoroacetate ([Hmim](CF₃COO)) as an ionic‐liquid medium in good to excellent yields (Scheme 1).     

Hollow fiber liquid phase microextraction as a preconcentration and clean-up step after pressurized hot water extraction for the determination of non-steroidal anti-inflammatory drugs in sewage sludge

A method for the quantitative determination of non-steroidal anti-inflammatory drugs (NSAIDs) in sewage sludge was developed and validated. The target compounds were extracted using pressurized hot water extraction (PHWE) and then purified and preconcentrated by three-phase hollow fiber liquid phase microextraction (HF-LPME) followed by LC–ESI-MS analysis. The PHWE was optimized with regard to the pH of solvent as well as other operational parameters. The optimum conditions were 0.01 M NaOH as the extraction solvent, temperature of 120 °C, pressure of 100 bar, static time 5 min, 5 cycles, flush volume 90% and purge time 60 s. Spike recoveries for sludge samples spiked at 200 ng g⁻¹ were in the range of 101–109% but for the native drugs in non-spiked sludge samples, recoveries were 38.9%, 59.8%, 90.3% and 47.8% for ketoprofen, naproxen, diclofenac and ibuprofen, respectively. Donor phase pH, ionic strength and extraction time were optimized for HF-LPME after PHWE. The optimum conditions were 2 h extraction at pH 1.5 without salt addition. Enrichment factors in the range of 947–1213 times were achieved (extraction recoveries were 23.6–30.3%) for HF-LPME after PHWE. The matrix effect on the ionization of drugs in LC–ESI-MS was also investigated. The results show that there is a smaller matrix effect (−8.9% to +14.6%) in comparison with other published values obtained using solid phase extraction (SPE) for clean-up after pressurized liquid extraction (PLE). Method detection limits (MDLs) and method quantification limits (MQLs) for different drugs were in the range of 0.4–3.7 ng g⁻¹ and 1.5–12.2 ng g⁻¹ in dried sludge samples, respectively. The characteristics of the proposed method were compared with those of other published works. The considerably lower ion suppression/enhancement and minimum use of organic solvents (a few microliters of di-n-hexyl ether) in the sample preparation step are two highlighted advantages of the proposed method in comparison with previously published works. The method was applied to determine NSAIDs in sewage sludge from Källby wastewater treatment plant (Lund, Sweden) in April, June, August and October 2010. The highest concentration level was recorded for ibuprofen in the April sewage sludge sample (588 ng g⁻¹) and all of the selected NSAIDs were detected in all the samples analyzed.