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Silica gel modified with 3-aminopropyltrimethoxysilane was anchored with nicotinaldehyde to prepare a new chelating surface (or matrix). It was synthesized and characterized by elemental analysis, cross-polarization magic-angle spinning C nuclear magnetic resonance (NMR) spectroscopy, diffuse reflectance infrared Fourier-transform spectroscopy, nitrogen adsorption-desorption isotherm, Brunauer-Emmett-Teller surface area, and Barrett-Joyner-Halenda pore sizes. The new surface exhibits good chemical and thermal stability as determined by thermogravimetry curves. This new organic-inorganic material was used for preconcentration of Hg(II), Pb(II), Zn(II), and Cd(II) from water prior to their determination by inductively coupled plasma atomic emission spectrometry. The optimum pH for quantitative sorption of these metal ions is in the range of 6-8, and the sorption capacity is in range of 486-1,449 μmol/g. By batch method, 95 % extraction takes ≤30 min. All the metals could be desorbed with a solution of hydrochloric acid (6 N) without loss of the expensive ligand. Solutions of the metal ions were prepared by dissolution of the nitrate solution. [ABSTRACT FROM AUTHOR]

Three coordination complexes, [Cu(L1)(2,2–bipy)]2n·3nH2O (1), [Cu(L1)(2,2–bipy)2]·xH2O (2: x = 3.5 and 3: x = 5), were synthesized by reactions of the flexible ligand 1,1´-methylenebis(5-methyl-pyrazole-4-carboxylic acid) (H2L1) and coligands 2,2'–bipyridyl (2,2-bipy) with Cu(OAc)2·H2O in different reaction condition, respectively. The structures of these complexes were established by elemental analysis, IR and single-crystal X-ray diffraction analysis. Complex 1 possessed a one-dimensional (1D) chainlike structure, (L1)2− group exhibited trans-configuration and coordinated to Cu(II) ions by carboxylate O atoms in µ2–k:O,O′; k:O′′′,O′′′ mode. In the similar subjectival structure of 2 and 3, (L1)2− anions also presented trans-configuration, but only one carboxylate group chelated to a Cu(II) ion, and the other carboxylate group remains free in a deprotonated form. The 1D chains in 1 were further assembled to a 3D supramolecular architecture via intermolecular C–H···O hydrogen bond. The mononuclear zwitterionic complexes 2 and 3 are further assembled into a 2D/3D supramolecular architecture by intermolecular hydrogen bonds and π···π interaction. The thermal and photoluminescent properties of 1–3 in the solid state have also been investigated. [ABSTRACT FROM AUTHOR]

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The current study includes organic synthesis of some new pyrazol derivatives from 2-amino thiazole by prepare diazonium salt from it with Ethyl Aceto Acetate as coupling compound to form Azo compound (B). From this azo compound, pyrazol Derivatives are prepared by closing the Aceto and Aster groups via hydrazine and phenyl hydrazine under Microwave irradiation respectively . The other step is the preparation of Chalcone derivative(CH) from Azo compound (B) with p-N,N-di methyl amino banzaldehyde. also pyrazol Derivative was prepared by reaction the Chalcone derivative with hydrazine hydrate in acidic and basic medium . These compounds are identified and confirmed by FT- IR, ¹HNMR, 13CNMR. [ABSTRACT FROM AUTHOR]

Three mononuclear coordination complexes of 1-butyl-2-((5-methyl-1H-pyrazol-3-yl)methyl)-1H-benzimidazole (L), namely [CoL]Cl2 (C1), [Co2L2]Cl2·H2O (C2) and [Zn2L2]Cl2 (C3), have been synthesized and characterized spectroscopically. Their single-crystal X-ray diffraction analysis revealed that C1 and C2 display pseudopolymorphism. The presence of N–H⋯Cl and C–H⋯Cl hydrogen bonding in the crystal structure of C1 and C3 assists the formation of a 2D hydrogen bonded sheet and orthogonal packing [2D sheet + a pair of 1D chains], respectively, leading to supramolecular structures. A combination of N–H⋯Cl, C–H⋯Cl, O–H⋯Cl, and C–H⋯O interactions results however in a 2D corrugated hydrogen bonded sheet with inclusion of water molecules in C2. Hirshfeld surface analysis confirms that hydrogen bonding and π-stacking contacts stabilize the crystal structures. These metal complexes display good performance towards their antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. In particular a normalized minimum inhibitory concentration as low as 6.25 μg mL−1 for the bacterial strains was recorded for C2. Its structure–bioactivity correlation is discussed in detail. [ABSTRACT FROM AUTHOR]

C15H13NO3, monoclinic, Cc (No. 9), a = 3.9230(3) Å, b = 26.578(2) Å, c = 11.7147(12) Å, β = 94.028(8)°, V = 1218.4(2) Å3, Z = 4, Rgt( F) = 0.0387, wRref( F2) = 0.0877, T = 173 K. [ABSTRACT FROM AUTHOR]

A new hybrid inorganic‐organic material, modified with a β‐keto‐enol‐bisfuran receptor, has been synthesized and used for heavy metal adsorption. The surface of this material revealed a porous structure, and full incorporation of the metal receptor into the hybrid material was confirmed. Systematic adsorption experiments were undertaken by varying pH, adsorption time, initial concentration, and temperature. A highly selective adsorption was detected for CdII, which reached equilibrium within only 25 min. Regeneration of our hybrid material is excellent with a simple regeneration process, thus opening important perspectives in water cleaning technologies. [ABSTRACT FROM AUTHOR]

Summary: In this research, the title compound was synthesized and characterized using spectroscopic analyses like FTIR and XRD. The compound's structure was optimized using Density Functional Theory (DFT) at B3LYP method with 6-311++G(d,p) basis set. The experimental parameters obtained by XRD were found to agree well with the theoretically calculated parameters. The title compound was studied using several methods, including FMOs, MEP, Hirshfeld surface analysis, 2D fingerprint plots, net charges, Electrophilicity-based Charge Transfer (ECT), Natural Bond Orbital analysis and global chemical reactivity descriptors. [ABSTRACT FROM AUTHOR]

C14H18N4O2, monoclinic, P21/c (no. 14), a=4.4260(9) Å, b=14.502(4) Å, c=11.455(3) Å, β=96.319(5)°, V=730.8(3) ų, Z=2, Rgt(F)=0.0712, wRref(F²)=0.1946, T=296(2) K. [ABSTRACT FROM AUTHOR]

Chelating adsorbents, based on the chemical modification of silica by an efficient host able to capture toxic metals, are the most popular materials for wastewater treatment. Herein, a novel inorganic–organic hybrid material incorporating a β-keto–enol bis-heterocycle structure (SiNPz-Fn) was synthesized and the structure of the host was confirmed by single crystal X-ray diffraction. This ligand was designed to introduce active lone-pair donor systems on the silica surface. The new material has been characterized using a set of suitable physical techniques, and was found to be an efficient adsorbent for Pb(ii), Zn(ii), Cu(ii) and Cd(ii) from aqueous solution. The influence of the solution pH, contact time, initial concentration, temperature, thermodynamics and co-existing interferent substances was also studied. The adsorption kinetics of Pb(ii), Zn(ii), Cu(ii) and Cd(ii) onto SiNPz-Fn can be well fitted with a pseudo-second-order model and the adsorption capacity of this material is evaluated as 87.71, 54.64, 28.81 and 10.77 mg g−1 for Pb(ii), Zn(ii), Cu(ii) and Cd(ii), respectively. An endothermic and spontaneous process was identified. The new material was used for the extraction of metals from natural water and promises good recyclability for at least five cycles, showing great potential in practical applications. [ABSTRACT FROM AUTHOR]

Amino poly-carboxylic acids (APCAs) offer unique binding properties as host molecules that can be tailored and potentially improved by incorporation into inorganic materials. Herein, we report the design and synthesis of a highly chelating and stable hybrid adsorbent based on silica-supported amino penta-carboxylic acid (SiDTPA) with a superior capability for water purification. The material was characterized using an appropriate set of spectroscopic and analytical techniques (EA, solid state 13C NMR, FTIR, TGA, SEM, STEM, XRD and BET surface area analysis) revealing a covalent organic framework and highly chelated mesoporous surface. Its adsorption studies highlight the influence of operating conditions, such as the contact time, initial concentration, pH, competitive extraction, temperature, thermodynamics and kinetics, on the adsorption of several potentially toxic metals from aqueous solutions and real water samples. The studies also reveal that the uptake of metal ions onto SiDTPA is a fast process, and reached its maximum within the first 20 min of contact time. The maximum sorption capacity of Cu2+, Zn2+, Cd2+ and Pb2+ was 2.40, 1.62, 0.85 and 0.3 mmol g−1, respectively. The adsorption process follows a pseudo-second-order kinetics and the positive values of ΔS° and ΔH° indicate the endothermic nature of the adsorption process, whereas a decrease of Gibbs free energy (ΔG°) with increasing temperature indicates the spontaneous nature of the adsorption process. Notably, the adsorbent can be regenerated continuously without affecting its extraction percentage. SiDTPA showed high effectiveness when compared to other described materials, and insights into the molecular-level phenomena governing this efficacy were provided by molecular dynamics (MD) simulations. [ABSTRACT FROM AUTHOR]

Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesismethods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported. [ABSTRACT FROM AUTHOR]

The development of low-cost catalytic systems that mimic the activity of tyrosinase enzymes (Catechol oxidase) is of great promise for future biochemistry technologic demands. Herein, we report the synthesis of new biomolecules systems based on hydrazone derivatives containing a pyrazole moiety (L1-L6) with superior catecholase activity. Crystal structures of L1 and L2 biomolecules were determined by X-ray single crystal diffraction (XRD). Optimized geometrical parameters were calculated by density functional theory (DFT) at B3LYP/6-31G (d, p) level and were found to be in good agreement with single crystal XRD data. Copper (II) complexes of the compounds (L1-L6), generated in-situ, were investigated for their catalytic activities towards the oxidation reaction of catechol to ortho-quinone with the atmospheric dioxygen, in an attempt to model the activity of the copper containing enzyme tyrosinase. The studies showed that the activities depend on four parameters: the nature of the ligand, the nature of counter anion, the nature of solvent and the concentration of ligand. The Cu(II)-ligands, given here, present the highest catalytic activity (72.920 μmol.L-1.min-1) among the catalysts recently reported in the existing literature. [ABSTRACT FROM AUTHOR]

Three new complexes namely [Cu(L1)H2O]·2H2O (1), [Cu2(L4)2(DMF)2(H2O)2](NO3)2 (4) and [{Cd2(L4)2Cl2(DMF)2}] (5), and two coordination polymers namely [Co(μ-L2)(DMF)2]·2H2O (2) and [Co(μ-L3)(DMF)2]·H2O (3) have been synthesized from a series of pyrazole-carboxylate ligands namely 1,1′-(ethane-1,2-diyl)bis(5-methyl-1H-pyrazole-3-carboxylic acid) (H2L1), 1,1′-(oxybis(ethane-2,1-diyl))bis(5-methyl-1H-pyrazole-3-carboxylic acid) (H2L2), 1,1′-(butane-1,4-diyl)bis(5-methyl-1H-pyrazole-3-carboxylic acid) (H2L3), and 2-(1′,5,5′-trimethyl-1H,1′H-[3,3′-bipyrazol]-1-yl)acetic acid (H2L4), and CuII/CdII/CoII ions. Single crystal structures of these compounds are discussed in the context of the effect of conformation of the ligands and supramolecular interactions observed within these edifices. Temperature-dependent magnetic data of 4 could be fitted best using two non-interacting CuII ions (S = 1/2) per molecule with giso = 2.28 and a temperature-independent paramagnetism, TIP = 1.75 × 10−5 cm3 mol−1. [ABSTRACT FROM AUTHOR]

In this study, we reported an efficient, alternative, and low-cost adsorbent for the efficient removal of Pb(II), Zn(II), Cd(II) and Cu(II) from water. The new hybrid material has been prepared by immobilizing a conjugated system (2Z)-1-(1,5-dimethyl-1H-pyrazol-3-yl)-3-hydroxybut-2-en-1-one on silica gel previously doped with 3-aminopropyltrimethoxysilane. The formed surface (SiNPz) was perfectly analyzed. Adsorption studies have demonstrated the ability to highlight the surface designed for efficient removal of above toxic metals from aqueous solutions using FAAS. The new material was used for the extraction of metals from natural water and showed efficiency results for toxic heavy metals. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to study the inhibition effect of 2-pyridinealdazine on the corrosion of mild steel in an acidic medium. The inhibition effect was studied using weight loss, electrochemical impedance spectroscopy, and Tafel polarization measurements.Design/methodology/approach Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy, X-ray diffraction and spectral and conformational isomers analysis of A (E-PAA) and B (Z-PAA) were performed were investigated.Findings 2-pyridinealdazine (PAA) acts as a good inhibitor for the corrosion of steel in 2.0 M H3PO4. The inhibition efficiency increases with an increase in inhibitor concentration but decreases with an increase in temperature.Originality/value This paper is intended to be added to the family of azines which are highly efficient inhibitors and can be used in the area of corrosion prevention and control. [ABSTRACT FROM AUTHOR]

C19H19N5O, triclinic, P1̅ (no. 2), a = 11.8865(6) Å, b = 12.6289(7) Å, c = 13.5579(7) Å, α = 74.552(2)°, β = 83.174(2)°, γ = 62.534(2)°, V = 1740.56(16) Å3, Z = 4, Rgt (F) = 0.0610, wRref (F2 ) = 0.1713, T = 100 K. [ABSTRACT FROM AUTHOR]

A pyridylpyrazole bearing a hydroxyethyl substituent group has been synthesized by condensation of (Z)-4-hydroxy-4-(pyridin-2-yl)but-3-en-2-one with 2-hydroxyethylhydrazine. The compound was well characterized and its structure confirmed by single crystal X-ray diffraction. Density functional calculations have been performed using DFT method with 6-31G* basis set. The HOMO-LUMO energy gap, binding energies and electron deformation densities are calculated at the DFT (BLYP, PW91, PWC) level. The electrophilic f(-) and nucleophilic f(+) Fukui functions and also the electrophilic and nucleophilic Parr functions are well adapted to find the electrophile and nucleophile centers in the molecule. The title compound has been tested for its DPPH radical scavenging activity which is involved in aging processes, anti-inflammatory, anticancer and wound healing activity. Compound is also found with a significant antioxidant activity, probably due to the ability to donate a hydrogen atom to the DPPH radical. [ABSTRACT FROM AUTHOR]

Novel 5,5-dimethyl-2,2-di(pyridin-2-yl)hexahydropyrimidine was synthesized in good yield by a one-pot condensation reaction of 2,2-dimethylpropane-1,3-diamine with di(pyridin-2-yl)methanoneusing dichloromethane as solvent at room temperature. The structure of the synthesized compound was assigned on the basis of its elemental analysis, UV-visible, ¹H-NMR, 13C-NMR, IR, and mass spectral data. [ABSTRACT FROM AUTHOR]

A series of new 2-aminobenzamide derivatives (1-10) has been synthesized in good to excellent yields by adopting both conventional and/or a time-efficient microwave assisted methodologies starting from isatoic anhydride (ISA) and characterized on the basis of their physical, spectral and microanalytical data. Selected compounds of this series were then tested against various bacterial (Bacillus subtilis (RCMB 000107) and Staphylococcus aureus (RCMB 000106). Pseudomonas aeruginosa (RCMB 000102) and Escherichia coli (RCMB 000103) and fungal strains (Saccharomyces cerevisiae (RCMB 006002), Aspergillus fumigatus (RCMB 002003) and Candida albicans (RCMB 005002) to explore their potential as antimicrobial agents. Compound 5 was found to be the most active compound among those tested, which showed excellent antifungal activity against Aspergillus fumigatus (RCMB 002003) more potent than standard Clotrimazole, and moderate to good antibacterial and antifungal activity against most of the other strains of bacteria and fungi. Furthermore, potential pharmacophore sites were identified and their activity was related with the structures in the solution. [ABSTRACT FROM AUTHOR]

This study aimed to remove carbamazepine from aqueous solutions, using functional silica phenylamine (SiBN), which is characterized and showed excellent chemical and thermal stability. Adsorbents based on silica were developed due to their unusually large surface area, homogenous pore structure, and well-modified surface properties, as silica sparked tremendous interest. It was determined to develop a novel silica adsorbent including phenylamine and amide (SiBCON). The adsorbents obtained were analyzed by various spectroscopy devices, including SEM, FT-IR and TGA analysis. The maximum removal rates for carbamazepine were 98.37% and 98.22% for SiBN and SiBCON, respectively, when optimized at room temperature, pH 9.0, initial concentration of 10 mg·L−1 and contact time of 15 min. Theoretical tools are widely used in the prediction of the power of interactions between chemical systems. The computed data showed that new amine modified silica is quite effective in terms of the removal of carbamazepine from aqueous solution. Calculation binding energies and DFT data showed that there is a powerful interaction between amine-modified silica and carbamazepine. [ABSTRACT FROM AUTHOR]

A new silica gel material covalently bonded with 1-(pyridin-2-yl) imine (SiNPn) was synthesized and well characterized by elemental analysis, FT–IR,13C NMR of the solid state, nitrogen adsorption-desorption isotherm, BET surface area, B.J.H. Pore sizes, thermogravimetry curves (TGA), and scanning electron microscope (SEM). The new chelating surface exhibits good chemical and thermal stability. The adsorption capabilities of this new system towards toxic metal ions (Hg2+, Cd2+, Pb2+, and Zn2+) were investigated using the batch method. The percentage limits of extraction were determined by atomic absorption measurements. [ABSTRACT FROM AUTHOR]

Porous silica has been chemically modified with thiophene using the heterogeneous route. This synthetic route involved the reaction of native silica, SiO2, with a commercial silylating agent, 3-glycidoxypropyltrimethoxysilane, followed by the immobilization of the thiophene chelating groups on the support. The resulting material has been characterized by thermogravimetry, FTIR spectra, and elemental analysis. The solid was also studied and evaluated by determination of the surface area using the BET equation, and the adsorption and desorption capability using the isotherm of nitrogen and B.J.H. pore sizes. The new synthesized material was employed in a batch method as adsorbent from aqueous solutions of Hg2+, Cd2+, Pb2+, Cu2+, Zn2+, K+, Na+, and Li+. [ABSTRACT FROM AUTHOR]

The immobilization of a thiophene-based tripodal ligand, with a donor sulfur, on the surface of an epoxide group containing a silica gel phase for the synthesis of a newly functionalized material based on porous silica-bound bi-thiophene tripodal ligand (SGBT) is described. The modified silica surface was characterized by 13C NMR of a solid sample, elemental analysis, and infrared spectra. This new material was also studied and evaluated by determination of the surface area using the BET equation, the adsorption and desorption capability using the isotherm of nitrogen and BJH pore sizes, respectively. The target material exhibits good thermal stability as determined by thermogravimetry curves. The synthesized material was utilized in column and batch methods for adsorption of Hg2+, Cd2+, Pb2+, Cu2+, Zn2+, K+, Na+, and Li+, and the material exhibits an affinity only towards toxic heavy metals. [ABSTRACT FROM AUTHOR]

C18H16N4O2, triclinic, P1̅ (no. 2), a = 10.9734(4) Å, b = 11.8835(5) Å, c = 13.0996(5) Å, α = 78.581(2)°, β = 78.542(1)°, γ = 83.725(2)°, V = 1636.68(11) Å3, Z = 4, Rgt (F) = 0.0439, wRref (F2 ) = 0.1182, T = 100 K. [ABSTRACT FROM AUTHOR]

The article discusses a study on the synthesis of solid membrane films that use the photopolymerisation containing the tetrapyrazole active monomers spread on a polyacrylonitrile support. The resulting materials were used to extract and facilitate the transport of Cadmim, Plumbum and Mercury. The new formulation prepared contains methacrylic monomer, styrene and photostart and the dense membranes were obtained through esterification of acyclic hydroxy-tetrapyrazoles with meth-acryloyl chloride.

Novel α,w-hydroxyoligosiloxane telechelics were synthesized by condensation of a functionalized monochlorosiloxanes with the well-defined α,w-disilanols followed by hydrosilylation reaction. The control of functionality, length, and purity of the resulting oligomers were ascertained by means of 1H NMR, 29Si RMN, IR, and GPC. [ABSTRACT FROM AUTHOR]

Removal of heavy metals from drinking water sources and rivers is of strategic health importance and is essential for sustainable ecosystem development, in particular in polluted areas around the globe. In this work, new hybrid inorganic-organic material adsorbents made of ortho- (Si-o-OR) or para-Schiff base silica (Si-p-OR) were synthesized and characterized in depth. These hybrid adsorbents show a high selectivity to Cu(II), even in the presence of competing heavy metals (Zn(II), Cd(II), and Pb(II)), and also demonstrate great reusability after five adsorption-desorption cycles. Maximum sorption capacity for Cu(II) was found for Si-o-OR (79.36 mg g−1) and Si-p-OR (36.20 mg g−1) in no less than 25 min. Energy dispersive X-ray fluorescence and Fourier transform-infrared spectroscopy studies demonstrate that this uptake occurs due to a chelating effect, which allows these adsorbents to trap Cu(II) ions on their surfaces; this result is supported by a theoretical study for Si-o-OR. The new adsorbents were tested against real water samples extracted from two rivers from the Oriental region of Morocco. [ABSTRACT FROM AUTHOR]