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In this work, three N'-arylidene-5-phenyl-1H-pyrazole-3-carbohydrazide (3a-3c), derivatives have been synthesized and fully characterized by IR, 1H & 13C NMR and ESI-MS using experimental and theoretical methods. Theoretical calculations were carried out by DFT/B3LYP method using 6-311++G(d,p) basis set. For theoretical IR, 1H & 13C NMR (with GIAO method), MEP, HOMO-LUMO energies analyses of compounds 3a-3c were performed over the optimized structures. All newly synthesized compounds were screened for their cytotoxicity, proylenpeptidase and α-glucosidase inhibitory activities. Compounds 3c showed significant anticancer activity against lung cancer cell line (H460) with the IC50 value 0.15 ± 0.01 µM. The other compounds exhibited prolyl endopeptidase (PEP) activity. Compounds 3a and 3c have demonstrated a potent α-glucosidase inhibitory activity with the IC50 value 360.4 ± 0.7 µM and 370.3 ± 1.17 µM, respectively. Furthermore, in-silico based molecular docking study was performed between the title ligands and lung cancer cell line-H460 protein: 1M17. The best affinity bond was observed between compound 3c and the protein 1M17 with an energy of −8.6 (kcal/mol), an inhibition constant of 0.496769 μM and an active hydrogen bond to three.

Porphyrins are an important class of ligands with a tremendous ability to capture metal ions closely related to the rich coordination chemistry of porphyrins. Herein we use this characteristic to develop silica gel grafted derivatives for water remediation applications. Therefore, two porphyrin derivatives, one with three and the other with four mercaptopyridyl units were grafted on silica gel functionalized with 3-aminopropyltriethoxysilane. The new adsorbents Si3PyS and Si4PyS were characterized using a suitable set of techniques confirming the covalent attachment of the porphyrins to the silica surface. Additionally, microscopy and N2 adsorption analysis confirmed the structural integrity and preservation of the mesoporous structure of Si during surface modification. The results show that both hybrid materials exhibit good chemical and thermal stability and an outstanding Cu2+ removal capability, with a chemical adsorption capacity of 176.32 mg g–1 and 184.16 mg g–1, respectively. These materials have also been used in real water and industrial wastewater samples with minimal interference in their adsorption capabilities. Density Functional Theory calculations were performed to confirm the good performance of the hybrid materials Si3PyS and Si4PyS towards metal ions. The functionalization of silica surface with porphyrin-based ligands bearing additional binding motifs drastically improves the adsorption capability of the new hybrids towards metal ions. The presence of pyridyl units brings a meaningful advantage, since both porphyrin core and appended pyridyl groups are able of binding Cu2+ ions with high affinity, contributing to the enhancement of the chelating features of the adsorbents prepared when compared with other ligands supported in silica-based materials. published

This study represents the first explorative investigation on the supramolecular structural diversity in Hg(II) coordination chemistry with triazole-thiourea ligands leading to a variety of mononuclear, binuclear, and coordination polymers: {[Hg(L1)2(L1–)2]} (1), {[Hg2(L1)2(μ2-I)2I2]·DMSO} (2), {[Hg(L2)(μ2-I)I]·MeOH}∝ (3), {[Hg2(μ-L3–)4]}∝ (4), {[HgCl(L4–)L4]·MeOH} (5), {[Hg2(L4)2(μ2-I)2(I)2]·2MeOH} (6), {[Hg2(μ2-L5–)4]}∝ (7), {[Hg2(μ2-Cl)2(L6–)2(L6)2]} (8), {[Hg2(μ2-Br)2(L6–)2(L6)2]} (9), and {[Hg2(μ2-I)2(L6–)2(L6)2]} (10). A reaction mechanism was suggested for the unexpected ligand rearrangement occurring in {[Hg2I3(μ3-L5′)]}∝ (11). The ligands were fully characterized including by X-ray crystallography and computational means. This includes six new triazole-thiourea based ligands, namely, 1-R-3-(4H-1,2,4-triazol-4-yl)thiourea (where R = methyl (L1), ethyl (L2), propyl (L3), isopropyl (L4), and its polymorph (L4-poly), allyl (L5), ethyl acetate (L6), and its solvate (L6_MeOH)). Under UV light excitation, 7, 10, and 11 exhibit visible photoluminescence of wide origin, ranging from ligand-centered (LC) fluorescence combined with organic-ligand-to-metal charge transfer (LMCT) emissive states in 7 and 10, up to halide-to-metal charge transfer (XMCT) combined with halide-to-ligand charge transfer (XLCT) emissive states in 11. The variable emission mechanisms in the obtained coordination polymers were elucidated by experimental proofs confronted with theoretical calculations of the electronic densities of states, proving that Hg(II) halide coordination polymers involving flexible 1,2,4-triazole-based ligands form a promising class of luminescent molecular materials.

A new pyrazole ligand, N,N-bis(2(1′,5,5′-trimethyl-1H,1′H-[3,3′-bipyrazol]-1-yl)ethyl)propan-1-amine (L) was synthesized and characterized by 1H-NMR, 13C-NMR, FT-IR and HRMS. The coordination ability of the ligand has been employed for the construction of a new family of coordination complexes, namely: [Cu2LCl4] (1), [ML(CH3OH)(H2O)](ClO4)2 (MII = Ni (2), Co (3)) and [FeL(NCS)2] (4). The series of complexes were characterized using single-crystal X-ray diffraction, HRMS, FT-IR and UV-visible spectroscopy. Moreover, the iron(II) analogue was investigated by 57Fe Mössbauer spectroscopy and SQUID magnetometry. Single-crystal X-ray structures of the prepared complexes are debated within the framework of the cooperative effect of the hydrogen bonding network and counter anions on the supramolecular formations observed. Furthermore, within the context of biological activity surveys, these compounds were reviewed against different types of bacteria to validate their efficiency, including both Gram-positive as well as Gram-negative bacteria. Enhanced behaviour towards Fusarium oxysporum f. sp. albedinis fungi, were detected for 1 and 4.

This study aims to explore the inhibitory action of certain derivatives of Schiff’s base, namely 4-(pyridin-2-ylimino) pentan-2-one (CE5),4-(pyrimidin-2-ylimino) pentan-2-one (CE4) and 4-((1H-tetrazol-5-yl) imino) pentan-2-one (CE20) against mild steel (MS) corrosion in 1 M HCl by the gravimetric, stationary and transient method. For additional information on the inhibitory properties of the studied compounds, scanning electron microscopy (SEM) and functional density theory (DFT) calculations were also performed. The effectiveness of the Schiff’s base derivatives studied follows the order: CE20 > CE4 > CE5. The electrochemical impedance curves show that the corrosion reaction is controlled by a charge transfer process, while the potentiodynamic polarization curves indicate that the synthesized compounds act as a mixed-type inhibitor. The adsorption process follows the Langmuir isotherm. Kinetic, as well as thermodynamic parameters, were calculated and discussed. The increase in EHOMO and decrease in gap energy ΔEgap lead to an increase in the inhibition efficiency. Results obtained from quantum chemical studies are in good agreement with quantum chemical parameters and experimental inhibition efficiencies.

The complexes: [CoL2](ClO4)2 (1), [FeL2](ClO4)2 (2), [NiL2](ClO4)2 (3) and [MnLCl2] (4), with L = diethyl-1,1′-(pyridine-2,6-diyl)bis(5-methyl-1H-pyrazole-3-carboxylate), were synthesized and fully characterized. Structural analysis revealed two distinct patterns influenced by the counter ions where L acts as a tridentate chelating ligand. The in vitro antitumor activity of L and L′ (diethyl 2,2′-(pyridine-2,6-diylbis(5-methyl-1H-pyrazole-3,1-diyl)) diacetate) as well as their metal complexes, was tested by the measurement of their cytostatic and cytotoxic properties towards the blood cancer mastocytoma cell line P815. We have also investigated their interactions with the antioxidant enzyme system. As a result, [MnL′Cl2] (1′) exhibited the strongest activity compared to reference cis-platin with no cytotoxicity towards normal cells PBMCs (Peripheral Blood Mononuclear Cells). On the other hand, the antioxidant enzyme activity showed that the efficiency of metal complex 1′ against P815 tumor cells was via the rise in the SOD activity and inhibition of CAT enzyme activity. This proof of concept study allows disclosure of a new class of molecules in cancer therapeutics.

Background Human and veterinary antibiotics are typically discharged as parent chemicals in urine or feces and are known to be released into the environment via wastewater treatment plants (WWTPs). Several research investigations have recently been conducted on the removal and bioremediation of pharmaceutical and personal care products (PPCPs) disposed of in wastewater. Results SiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and nitrogen adsorption–desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the experimental and theoretical of different adsorption coefficients. The Langmuir and Freundlich adsorption models were used and the study showed a better match with the Freundlich model with a capacity of removal reached up to 420 mg g−1. The removal capacity was dependent on pH and increased by increasing pH. The removal percentage reached 91;5% at pH = 8. The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94% when increased pH. The sample was simply regenerated by soaking it for a few minutes in 1 N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. The thermodynamic study also showed endothermic, increasing randomness and not spontaneous. The free energy was 2.71 kJ/mol at 320 K. The findings of the DFT B3LYP/6–31 + g (d, p) local reactivity descriptors revealed that nitrogen atoms and π-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The negative values of the adsorption energies obtained by molecular dynamic simulation indicated the spontaneity of the adsorption process. Conclusion The global reactivity indices prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indices concluded that the active centers for the adsorption process are the nitrogen atoms and the π-electrons of the pyrimidine and benzene rings. Furthermore, the positive value of the maximum charge transfer number (ΔN) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.

Garcia, Yann/0000-0002-3105-0735; karrouchi, khalid/0000-0002-8075-8051; Chkirate, Karim/0000-0002-9996-4963; RADI, Smaail/0000-0002-5062-6904; Sebbar, Nada Kheira/0000-0003-4944-1010 WOS: 000514598200055 Three mononuclear coordination complexes of 1-butyl-2-((5-methyl-1H-pyrazol-3-yl)methyl)-1H-benzimidazole (L), namely [CoL]Cl-2 (C1), [Co2L2]Cl-2 center dot H2O (C2) and [Zn2L2]Cl-2 (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 center dot center dot center dot Cl and C-H center dot center dot center dot 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 center dot center dot center dot Cl, C-H center dot center dot center dot Cl, O-H center dot center dot center dot Cl, and C-H center dot center dot center dot 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 pi-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 mu g mL(-1) for the bacterial strains was recorded for C2. Its structure-bioactivity correlation is discussed in detail. bilateral WBI action with Morocco (COP 22 Program); Fonds De La Recherche Scientifique - FNRSFonds de la Recherche Scientifique - FNRS [PDR T.0102.15, CDR 33694457]; [PYOFEN.1906.19.001] This work was supported by a bilateral WBI action with Morocco (COP 22 Program 2018-2022), the Fonds De La Recherche Scientifique - FNRS (PDR T.0102.15, CDR 33694457) and project No. PYOFEN.1906.19.001.

The corrosion inhibition of mild steel in 1 M hydrochloric acid solution by some bipyrazole derivatives N,N'-dimethyl-N,N'-bis(1H-pyrazol-1-ylmethyl)ethane-1,2-diamine (3a), 1-{[{2-[[(3-carboxy-5-methyl-1H-pyrazol-1-yl)methyl](methyl)amino]ethyl}(methyl)amino]methyl}-5-methyl-1H-pyrazole-3-carboxylic acid (3b) and 1-{[{2-[{[3-(methoxycarbonyl)-1H-pyrazol-1-yl]methyl}(methyl)amino]ethyl}(methyl)amino]methyl}-1H-pyrazole-3-carboxylic acid (3c) has been studied in relation to the concentration of the inhibitors as well as the temperature using chemical (weight loss) and electrochemical (ac impedance and dc polarisation) techniques. All the methods employed are in reasonable agreement. The protection efficiency increases with increasing inhibitors concentration and with increasing temperature. The thermodynamic functions of dissolution and adsorption processes were calculated from weight loss measurement and the interpretation of the results are given. Adsorption of inhibitor on the carbon steel surface is found to obey the Langmuir adsorption isotherm.

Herein we report the synthesis, DFT calculations, and molecular docking studies of a pyrazole derivative, (E)-N'-benzylidene-5-methyl-1H-pyrazole-3-carbohydrazide (E-BMPC) as α-glucosidase and α-amylase inhibitor. Molecular structure of E-BMPC has been confirmed by single crystal X-ray diffraction (XRD), FTIR, 1H, and 13C NMR spectra. In addition, density functional theory (DFT) calculations on E-BMPC were carried out to obtain frontier molecular orbital energies and first-order static hyperpolarizability (β). The α-amylase and α-glucosidase enzyme inhibitory of E-BMPC was also tested. E-BMPC displayed moderate inhibitory activity with IC50 values 310.57 ± 2.67 and 182.19 ± 3.20 against α-glucosidase and α-amylase enzymes, respectively. Molecular docking analysis provided the inhibition constant of E-BMPC molecule for α-amylase enzyme as 33.60 µM. Both in vitro and in silico enzyme inhibition studies showed that E-BMPC molecule is a better inhibitor for α-amylase than α-glucosidase. The β parameter for the molecule under investigation was also calculated as 4.2 × 10−30 esu.

BackgroundHuman and veterinary antibiotics are typically discharged as parent chemicals in urine or feces and are known to be released into the environment via wastewater treatment plants (WWTPs). Several research investigations have recently been conducted on the removal and bioremediation of pharmaceutical and personal care products (PPCPs) disposed in wastewater. ResultsSiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and nitrogen adsorption-desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the experimental and theoretical of different adsorption coefficients. The Langmuir and Freundlich adsorption models were used and the study showed better match with Fruendlich model. The removal capacity was depending on pH and increased by increasing pH The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94 %. The sample was simply regenerated by soaking it for a few minutes in 1N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. Thermodynamic study also showed endothermic, increasing randomness and not spontaneous in nature. The findings of the DFT B3LYP/6-31+g (d,p) local reactivity descriptors revealed that nitrogen atoms and p-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The negative values of the adsorption energies obtained by molecular dynamic simulation indicated the spontaneity of the adsorption process. ConclusionThe global reactivity indics prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indices concluded that the active centers for the adsorption process are the nitrogen atoms and the p-electrons of the pyrimidine and benzene rings. Furthermore, the positive value of the maximum charge transfer number (DN) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.

The removal of heavy metals is attracting considerable attention due to their undesirable effects on the environment. In this investigation, a new adsorbent based on silica functionalized with pyridin-2-ylmethanol (SiPy) was successfully synthesized to yield to a hybrid material. FTIR, SEM, TGA, and specific surface area analysis were used to characterize the structure and morphology of the SiPy hybrid material. Various heavy metal ions such as Cu(ii), Zn(ii), Cd(ii), and Pb(ii) were selected to examine the adsorption efficiency of the newly prepared adsorbent, optimized at varying solution pH, contact time, concentration, and temperature. The adsorbent SiPy displayed good adsorption capacity of 90.25, 75.38, 55.23, and 35.12 mg g

Background: Pyrazole is an important class of heterocyclic compound, has been shown to exhibit diverse biological and pharmacological activities such as anti-inflammatory, anti-cancer, antioxidant, etc. Methods: In this study, a series of novel 3,5-dimethyl-1H-pyrazole derivatives containing hydrazine 4a-l have been synthesized via the reaction of the 2-(3,5-dimethyl-1H-pyrazol-1-yl)acetohydrazide. All synthesized compounds have been tested for their in vitro antioxidant activities via utilization of 1,1-biphenyl-2-picrylhydrazyl (DPPH) as a free radical scavenging reagent. Results: The data reported herein indicates that compound 4k showed potential radical scavenging capacity and compounds 4f and 4g exhibited best activity for the iron binding while comparing with positive controls. Conclusion: Good activity was noted for some compounds. In particular, compound 4k showed the highest antioxidant activity with IC50 values of 22.79 ± 3.64 and 1.35 ± 0.66 μg/mL in the DPPH and ABTS tests, respectively.

The pollution of water resources due to the disposal of toxic heavy metals has been a growing global concern for the last decades. For this purpose, the search for effective and economic material based adsorbents is required, due to the efficiency of the process. In this work, a novel inorganic-organic hybrid material based on silica chemically modified with a porphyrin (SiNTPP), with a high metal removal efficiency, was developed. The new material was characterized using a set of suitable techniques such as 13C NMR of the solid state, elemental analysis, FTIR, nitrogen adsorption-desorption isotherm, BET surface area, BJH pore sizes and scanning electron microscopy (SEM). The new material surface exhibits good chemical and thermal stability based on the obtained thermogravimetric curves (TGA). An adsorption study was accomplished to investigate the effect of porphyrin-silica hybrid on the removal of Pb(II), Zn(II), Cd(II) and Cu(II) from aqueous solutions using a batch method. The effect of various parameters, such as initial metal concentration, pH, temperature, as well as the kinetics and thermodynamics for sorption on SiNTPP were investigated. The studies demonstrate that adsorption is fast, as proved by the equilibrium achievement within 25min. The metals removal from aqueous solution are better adapted to the Langmuir isotherm model than to the Freundlich model. The thermodynamic parameters (ΔG°, ΔH° and ΔS°) disclose that the process was endothermic and spontaneous in nature, and the adsorption process follows a pseudo-second order kinetics. The adsorbent can be regenerated continuously without affecting its extraction percentage. Its effectiveness is highly justified compared to previous described materials.

Efficient materials capable of capturing toxic metals from water are widely needed. Herein, a new pyridylpyrazole-β-ketoenol receptor, X-ray diffraction analyzed, was covalently incorporated into the silica surface to produce solid and recyclable adsorbent particles. The new material, fully characterized, revealed extremely efficient removal of toxic metals from water, with a selectivity order of Pb(II) > Zn(II) > Cu(II) > Cd(II). The adsorption was exceptionally rapid at optimum pH and concentrations, showing Pb(II) removal of 93 mg g–1 within 5 min and maximum Pb(II) adsorption of 110 mg g–1 after only 20 min. Sorption isotherms agreed well with the Langmuir model suggesting a monolayer adsorption, whereas kinetics agreed with the pseudo-second-order model suggesting a chemisorption binding mechanism. Thermodynamics of adsorption were fitted with an endothermic and spontaneous process. The material, recyclable for at least five cycles, is therefore promising for the cleanup of water polluted by toxic metals, especially lead.

© 2018 Elsevier B.V. The synthesis, spectroscopic characterization, reactivity study and evaluation of antioxidant and α-glucosidase inhibitory activities of two Schiff bases containing 1,2,4-triazole and pyrazole rings namely: 4-((4-methoxybenzylidene)amino)-5-(5-methyl-1H-pyrazol-3-yl)-4H-1,2,4-triazole-3-thiol 3a and 4-((4-(dimethylamino)benzylidene)amino)-5-(5-methyl-1H-pyrazol-3-yl)-4H-1,2,4-triazole-3-thiol 3b were reported in the present work. Reactive properties of the two compounds have been investigated by means of combination of DFT calculations, molecular dynamics (MD) simulations and drug likeness parameters, followed by calculations of molecular electrostatic potential (MEP) and average local ionization energy (ALIE) values. Additionally, the sensitivity of 3a and 3b towards the autoxidation mechanism has been investigated by the concept of bond dissociation energies for hydrogen abstraction (H-BDE). α-glucosidase inhibition assay revealed that the two compounds displayed significant inhibitory potentials in terms of relative IC50 values as compared to that of the reference drug (Acarbose). In addition, the antioxidant activity of the synthesized compounds were determined in vitro by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and ferric reducing antioxidant power (FRAP) methods. Results revealed that the compound 3a is a potent antioxidant agent.

In the present study, two pyrazole-acetamide derivatives namely N‑(2‑aminophenyl)‑2‑(5‑methyl‑1H‑pyrazol‑3‑yl) acetamide (L1) and (E)‑N‑(2‑(1‑(2‑hydroxy‑6‑methyl‑4‑oxo‑4H‑pyran‑3‑yl)ethylideneamino)phenyl)‑2‑(5‑methyl‑1H‑pyrazol‑3‑yl) acetamide (L2) have been synthesized and characterized by infrared spectrophotometry (IR), nuclear magnetic resonance spectroscopy (NMR) and electrospray ionization-mass spectrometry (ESI-MS). Two coordination complexes of L1 and L2, namely [Co(L1)2(EtOH)2]·Cl2 (1) and [Cu(L2)]·H2O (2), respectively have been synthesized and characterized by elemental analysis and spectroscopic studies. The solid state structure of these two complexes was established by single crystal X-ray crystallography. In complex 1, the amide O and pyrazole N atoms of two molecules of L1 take part in coordination with octahedral Co(II) ions, the remaining two coordination sites being occupied by two EtOH molecules leading to a N2O4 coordination environment. On the other hand, the imine N atoms, pyrazole N and O atoms of the 2‑hydroxy‑6‑methyl‑4H‑pyran‑4‑one function present in L2 are involved in coordination with Cu(II) ions, resulting in a distorted square planar geometry displaying a N2O4 chromophore, in complex 2. The crystal packing analysis of 1 and 2, revealed 1D and 2D supramolecular architectures respectively, via various hydrogen bonding interactions, which are discussed in the present account. Furthermore, the antioxidant activity of the ligands and their complexes were determined in vitro by 1,1‑diphenyl‑2‑picrylhydrazyl (DPPH), 2,2′‑azino‑bis(3‑ethylbenzothiazoline‑6‑sulphonic acid (ABTS) and ferric reducing antioxidant power (FRAP), showing that the ligands L1 and L2 and complexes 1 and 2 present significant antioxidant activity.

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A new crystal, i.e, (E)-5-methyl-N′-(pyridin-2-ylmethylene)-1H-pyrazole-3-carbohydrazide (E-MPPC) has been synthesized and characterized by using FT-IR, UV-Vis, 1H-NMR, 13C-NMR, ESI-MS and single-crystal X-ray diffraction. In addition, a density functional theory study for the title compound was carried out. The theoretical geometry of the ground state and the electronic structure of the title compound were optimized by the DFT/B3LYP method in conjunction with 6-311++G(d,p) basis set. E-MPPC was evaluated in vitro for their α-glucosidase enzyme inhibition. The title compound displayed moderate inhibitory activity with IC50 value of 714.25 ± 8.33 µM against α-glucosidase enzyme. In addition, molecular docking study was performed to investigate how E-MPPC interacts with the protein structure of α-glucosidase enzyme. Final intermolecular energy and estimated inhibition constant for this docking study were obtained as -5.50 kcal/mol and 173.57 µM, respectively. The first order static hyperpolarizability (β) parameter for E-MPPC was also calculated as 11.2×10−30 esu. Natural bond orbital analysis was also executed to investigate intramolecular charge transfer interactions in the title compound.

The new (Z)-pyrazol β-keto-enol as model-molecule has been prepared in accepted high yield; the structure was investigated by X-ray single crystal diffraction (XRD) and Density Functional Theory (DFT) modeling. Several hydrogen bonds interactions were recorded experimentally via XRD and theoretically via Hirshfeld surface analysis (HSA) calculations. The recorded vibrational frequencies FT-IR were further compared to computed ones. Natural Population Analysis (NPA), Mulliken Atomic Charge (MAC), and Molecular Electrostatic Potential (MEP) has been carried out to complete the set of theoretical tools. The HOMO/LUMO, density of state (DOS) and TD-SCF/DFT were applied to compare these quantum parameters with experimental electron transfer and direct optical activity. DFT calculations, natural bond orbital (NBO) analysis and non-covalent interactions (NCI) analysis were used to explore the mechanism of the single proton keto-enol intra-migration tautomerization reaction. Additionally, the desired compound was screened for its in-vitro α-amylase and α-glucosidase inhibitory activities. The title compound reflected a potent inhibitory activity α-glucosidase enzyme with IC50 value of 72.20 ± 1.50 µM. Moreover, the solved 3D-crystal structure was used for 1BNA DNA docking evaluation.

The reaction of 1,5,5′-trimethyl-1H,1′H-3,3′-bipyrazole (Hbpz) with copper and manganese salts (Cu(BF4)2·6H2O, MnCl2·4H2O and Mn(NCS)2) leads to the formation of three mononuclear coordination complexes [Cu(Hbpz)3](BF4)2 (1), [Mn(Hbpz)2Cl2]·CH3CN (2) and [Mn(Hbpz)2(NCS)2]·Et2O (3). These compounds have been characterized using single crystal X-ray diffraction and infrared spectroscopy. The single crystal structures of 1, 2 and 3 are discussed in the context of the effect of hydrogen bonding functionalities and counter anions on the supramolecular structural diversities observed in these new coordination complexes.

Efficient hybrid materials based adsorbents are highly recommended for potentially toxic metals removal from polluted water media. Herein, novel silica particles modified with a new bispyrazolylpropane Schiff base were synthesized and characterized using relevant physical techniques. The resulting hybrid material (SiNAL3) was studied for its ability to uptake ZnII, CuII, PbII and CdII ions in aqueous solution via kinetics studies. The maximum adsorption capacities of SiNAL3 for ZnII, CuII, PbII and CdII were approximately 1.23, 0.32, 0.29 and 0.23 mmol g−1, respectively, with an equilibrium reached after only 25 min for all metals. The adsorption process was found spontaneous and endothermic. Interestingly, our hybrid material could selectively adsorb ZnII in the presence of other metal ions from an aqueous solution, a useful property which was applied to real water samples. The adsorbent can be easily reused with no significant decrease in adsorption capacity after not less than five adsorption-desorption cycles, demonstrating its high stability.

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.

In this work, a novel crystal i.e. (E)-N'-(4-chlorobenzylidene)-5-phenyl-1H-pyrazole-3-carbohydrazide has been synthesized and characterized using various spectroscopic techniques. The (E)-configuration of the azomethine (N CH) was confirmed by single crystal X-ray analysis. The molecule crystallizes in the monoclinic space group, P21/c, a = 15.629(9) A, b = 7.152(4) A, c = 14.707(9) A, β = 111.061(15)°, V = 1534.1(6) A3 and Z = 4. In addition, the elucidated molecular structure was confirmed by comparing the predicted Z-matrix geometries and spectroscopic data with the experimental ones. DFT calculations have been carried out in gas and IEFPCM solvent at the B3LYP/6–31+G(d,p). The in vitro anti-diabetic potential of the title compound was evaluated against α-glucosidase and α-amylase enzymes. Molecular docking studies showed that the various interactions tightly anchored the title compound to the active site, which makes it a more potent α-glucosidase inhibitor compared to well-known Acarbose.

New bi-Pyrazol-Carbohydrazides, N,N-bis (3-Carbohydrazide-5-methylpyrazol-1-yl) methylene (M2PyAz) and 1,4-bis (3-Carbohydrazide-5-methylpyrazol-1-yl) butane (B2PyAz), were synthesized and their inhibitor effect against mild steel (MS) corrosion in 1 M HCl solution has been evaluated. Comparative study of inhibitory action of M2PyAz and B2PyAz was conducted first using weight loss measurements (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and theoretical computational methods. The inhibition efficiencies of M2PyAz and B2PyAz can reach 98.6% and 87.8% respectively when the optimal concentration is 10–3 M. This result indicates that M2PyAz behave as excellent corrosion inhibitor towards MS because of its molecular size giving a denticity of electron donor atoms. EIS results indicate that the charge transfer resistance increases with augmentation concentration for both inhibitors and the MS corrosion in this system is controlled by a charge transfer process. PDP curves suggest that the M2PyAz and B2PyAz act as mixed type corrosion inhibitors. Free energy of adsorption obtained from the Langmuir isotherm model for both M2PyAz and B2PyAz implies that both molecules inhibit the acid attack mainly by chemisorption. WL-measurements were carried out in temperature range of 308–348 K, illustrating approximately 98.5% and 89% inhibitory efficiency respectively for M2PyAz and B2PyAz after 6 h immersion at 308 K in 1 M HCl solution. SEM images indicates the protective layer growth on the surface of metal in the presence of both inhibitors. SEM images analysis in the presence of both inhibitors confirmed the electrochemical outcomes. Density functional theory (DFT) method and molecular dynamics simulations (MDs) application suggest that M2PyAz and B2PyAz can show excellent corrosion inhibition character. The trend of reactivity of both molecules M2PyAz and B2PyAz is in agreement with experimental study.

International audience; In this paper, the effect of Keto-enol derivatives namely (Z)-3-hydroxy-1-(pyridin-2-yl)but-2-en-1-one (KE-1) and (Z)-1-(1,5-dimethyl-1H-pyrazol-3-yl)-3-hydroxy-3-(pyridin-2-yl)prop-2-en-1-one (KE-2)on the inhibition of carbon steel (CS) corrosion in 1 M HCl has been studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and quantum chemical study. Weight loss measurements indicate that these compounds reduce the corrosion rate of carbon steel in acidic solution and the inhibition effect increases with the inhibitors concentration but decreases with temperature. The electrochemical polarization study revealed that the tested Keto-enol derivatives are mixed type. EIS show that the KE-1 and KE-2 form an adsorptive layer on the metallic surface. The adsorption of the KEs on the carbon steel surface obeys the Langmuir adsorption isotherm. The results of quantum chemical calculations and Monte Carlo simulation studies are in good agreement with experimental results.

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.

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.

The extraction and separation of heavy metals with several hybrid sorbents has been recognized as a promising green methodology. We present a novel and efficient host based on a modified silica gel with a bis(pyrazole)butane derivative as a chelating ligand; it was synthesized and studied for its adsorption capacity towards toxic heavy metals in aqueous media. The success of the synthesis of SiNAL4 was concluded from elemental analysis, Fourier transform-infrared spectroscopy, solid state 13C NMR, nitrogen adsorption–desorption isotherm, BET surface area, BJH pore size, scanning electron microscopy and thermogravimetry analysis. The effectiveness, regenerability and stability of the studied adsorbent were demonstrated. The optimum conditions for the removal of selected toxic metal ions were found to be pH = 6 and 25 min of contact time with the hybrid material. The maximum levels of ZnII, PbII, CdII and CuII uptake by the hybrid material were 86.51, 35.26, 26.96 and 20.24 mg g−1, respectively. The equilibrium isotherm models of the adsorbent were better described by a Langmuir model. The kinetics of heavy metal adsorption of the hybrid material followed a pseudo-second-order model and the thermodynamic parameters confirmed the spontaneous adsorption, and the spontaneity increases with the increase in temperature. The architecture of the hybrid material, when adsorbing the metal on the surface of the inorganic silica, was revealed using single crystal X-ray diffraction of a model material capturing CuII ions thanks to ligand coordination. Finally, the hybrid material was used in the treatment of river waters containing ZnII and CdII. The quantitative removal of the toxic metals under study from real aqueous solutions confirms the effectiveness of this new adsorbent compared to several previously described materials.

During the last years, contamination of water by heavy metals has become a serious health hazard and environmental problem. In particular, mercury, lead, cadmium and zinc are considered as the most dangerous elements and are included on the US Environmental Protection Agency's (EPA) list of priority pollutants. To this end, the search for an effective material based adsorbent is a well-established technology. In this work, a novel and efficient host for the above toxic metals was synthesized by covalent immobilization of a new (E)-3-((2-nitrobenzylidene)amino) propan-1-ol Schiff's base receptor onto silica in a heterogeneous way to yield the material Si-CSB. The functionalized porous surface has been analyzed through elemental analysis, FT-IR spectroscopy, solid state 13C NMR, nitrogen adsorption–desorption isotherms, BET surface area, Barrett–Joyner–Halenda (BJH) pore diameters methods and thermogravimetric analysis (TGA). The new material showed great thermal and chemical stabilities examined in various acidic and buffer solutions. The adsorbent was applied in solid-phase extraction (SPE) and showed quantitative retention of Hg2 +, Pb2 +, Cd2 + and Zn2 + compared to previous described materials. The adsorption capability towards toxic metals was studied using kinetics, pH and temperature effects prior to their determination by ICP-AES. Adsorption was rapid as evidenced by equilibrium achieved within 25 min. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) revealed that the adsorption was spontaneous and endothermic. Alkali coexisting ions did not interfere with separation and determination. The material can be used continuously without reducing its extraction percentage. The newly synthesized material appears to be a low cost, effective and alternative adsorbent for efficient removal of heavy metals from aqueous solution.

A series of Schiff bases of 4-amino-1,2,4-triazole derivatives containing pyrazole (5a-h) were synthesized from condensation of 4-amino-5-(5-methyl-1H-pyrazol-3-yl)-4H-1,2,4-triazole-3-thiol (3) derivative with various aromatic aldehydes (4a-h). The structures of the synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, and mass spectrometry. All the synthesized compounds (5a-h) were screened for their in vivo analgesic and in vitro antioxidant activities revealing significant analgesic and antioxidant properties.

Water pollution by toxic elements represents a significant risk to the environment and human ecosystem, and a number of efforts are developed to find a suitable solution. In this work, a new adsorbent based on silica gel as an inert material modified on surface by a pincer ligand was prepared. The hybrid material has been synthesized via a simple Schiff base reaction and characterized by several relevant physical methods. The adsorbent shows an extremely rapid efficiency in removal of copper (less than 8 min) with maximum sorption capacity of 1.90 mmol g−1 and a rapid efficiency for zinc, cadmium and lead (less than 20 min) with adsorption capacities 0.52, 0.49 and 0.43 mmol g−1, respectively. A kinetic study shows that the sorption can be described by a pseudo second-order model, and that the process is thermodynamically spontaneous and endothermic. The adsorbent shows a high selectivity to Cu(II) and a great reusability after five adsorption-desorption cycles. Theoretical, energy dispersive X-ray fluorescence (EDX) and Fourier transform-infrared spectroscopy studies demonstrate that the uptake occurs by a coordination reaction between metal ions and the pincer ligand on the surface of the adsorbent. The efficiency of this new hybrid material was confirmed in removal of Cu(II) from real water samples originating from Abidjan Atlantic sea bay, one of the most polluted region in West Africa, as well as from rivers located near Oujda, Morocco.

In this present work, the newly synthesized compound E)-N’-(5-bromo-2-hydroxybenzylidene)isonicotinohydrazide (2) has been synthesized and characterized by IR, 1H &13C NMR, ESI-MS and single crystal X-ray diffraction analysis using experimental and theoretical methods. The molecular geometry, vibrational frequencies, frontier molecular orbital (HOMO-LUMO) energies and thermodynamic properties of the title molecule were explored using Density Functional Theory (DFT) calculation via B3LYP method with 6–31++G (d,p) basis set. Moreover, Hirshfeld and Molecular electrostatic potential (MEP) surfaces analyses were investigated. In addition, the title compound was evaluated for their in vitro antidiabetic activity against α-glucosidase and α-amylase enzymes. Finally, Molecular docking studies were performed between the title ligand and 1CLV/2ZE0 enzymes. Docking calculations showed that the 2-2ZE0 complex is more stable than 2-1CLV complex, since it has the best inhibitory impact whose their total energy score equal to −108.68 kcal/mol. Docking results reveal that the main interaction forces are H-bond and van der Waals interactions.

Corrosion inhibition is a vast area of research and its development is attracting increasing attention from researchers. Given the different biological activities that present these compounds, in the present work, we investigated two dimethyl-1H-pyrazole derivatives namely: (E)-N'-benzylidene-2-(3,5-dimethyl-1H-pyrazol-1-yl)acetohydrazide (DPP) and E)-N'-(4-chlorobenzylidene)-2-(3,5-dimethyl-1H-pyrazol-1-yl)acetohydrazide (4-CP) as corrosion inhibitors for mild steel (MS) in 1 M HCl using weight loss (WL), electrochemical techniques [potentiodynamic (PP) polarization, electrochemical impedance spectroscopy (EIS)], surface examinations by scanning electron microscopy (SEM). Theoretical studies such as quantum chemical and molecular simulations studies were used to support the experimental findings. Analyses on mass loss (ML) and electrochemical properties confirmed adsorption of inhibitor as a protective layer on the surface of MS. The inhibition efficiency of DPP and 4-CP was enhanced as the concentration of inhibitors increased but decrease with rising temperature. The maximum inhibition efficiency for DPP and 4-CP at 10−3 M concentration has been obtained 80 % and 94 % respectively. Analysis of adsorption isotherms revealed that adsorption of DPP and 4-CP on MS surface follows Langmuir isotherm. Potentiodynamic polarization study confirmed that DPP and 4-CP are of mixed-kind inhibitors. EIS investigations displayed that the polarization resistance raised to 93.7 Ω cm2 and 287.7 for DPP and 4-CP, respectively at 10-3 M. Furthermore, to get detailed electronic/atomic-level findings regarding the dimethyl-1H-pyrazole derivatives interactions over the MS substrate, theoretical investigations applying molecular dynamics (MD) and density functional theory (DFT) methods were conducted. The results extracted from these approaches affirmed the DPP and 4-CP adsorption on the MS adsorbent.

New crystal, (E)-N’-(4-(dimethylamino)benzylidene)-5-methyl-1H-pyrazole-3-carbohydrazide (3) has been synthesized and characterized by FT-IR, NMR, ESI-MS and single crystal X-ray diffraction (XRD). The optimized molecular structures of free base and cationic species of (3) in gas phase and aqueous solution, vibrational frequencies and, corresponding vibrational assignments have been investigated experimentally and theoretically by using the B3LYP/6-31G∗ and B3LYP/6–311++G∗∗ methods. High solvation energy values are observed for both species of (3) in solution while the NBO and AIM studies support the higher stability of the cationic species in solution. The high energy values ΔEσ→σ∗ and ΔEσ→π∗ transitions, due to the planarity of both CH3 groups linked to N atom, could support the high reactivities of its free base and cationic species, as compared with naloxone, cocaine and scopolamine. Complete vibrational assignments of 105 and 108 vibration modes expected for free base and cationic species of (3) together with the corresponding harmonic force constants are here reported. In vitro antidiabetic and antioxidant activities were revealed for (3). The molecular docking studies of the title compound revealed that it may exhibit anti-diabetic activity via inhibition of α-glucosidase PDB: 3A4A enzyme.

The inhibition of mild steel corrosion in 1.0 M HCl by some hydrazine derivatives namely: (1E,2E)-1,2-bis(thiophen-2-ylmethylene)hydrazine (PP2) and (1E,2E)-1,2-bis(1H-pyrrol-2-ylmethylene)hydrazine (PP3) has been investigated using weight loss, electrochemical studies, SEM and quantum chemical calculations. The results showed that PP3 is the best corrosion inhibitor among the three compounds studied and the inhibition efficiency increases with increase in concentration for all the inhibitors. The adsorption of inhibitor molecules on mild steel surface was found to be spontaneous and obeyed the Langmuir adsorption isotherm. Potentiodynamic polarization investigations indicated that the studied inhibitors were mixed type inhibitors. Electrochemical Impedance Spectroscopic measurements show that the inhibitors form an adsorptive layer on the metallic surface. Some of the inhibitors' quantum chemical parameters are calculated with the DFT method at the B3LYP/6-31G(d,p) level of theory. Among the calculated parameters, the LUMO energy, energy gap between the HOMO and LUMO, dipole moments (μ), global chemical hardness (η), softness (σ), and the fraction of electrons transferred from the inhibitor to the iron surface (ΔN) could well describe the experimental observations.

A new library of N,N,N',N' -tetradentate pyrazoly compounds containing a pyrazole moiety was synthesized by the condensation of (3,5-dimethyl-1H-pyrazol-1-yl)methanol 2a or (1H-pyrazol-1-yl)methanol 2b with a series of primary diamines in refluxed acetonitrile for 6h. The antifungal activity against the budding yeast Saccharomyces cerevisiae, as well as the antibacterial activity against Escherichia coli of these new tetradentate ligands were studied. We found that these tetradentate ligands act specifically as antifungal agents and lack antibacterial activity. Their biological activities depend on the nature of the structure of the compounds.

This study aims to prepare and develop several vehicles chelation polydentate supported ligands and then installed it using sol-gel or polymerization or to be susceptible to imply conjunction with the highly toxic heavy metal ions in the water, and disrupted the underground water used for drinking or agriculture, including cadmium ions. As the process of interaction between ligands and heavy metals depends on the circumstances of surrounding conditions which are treated in this research. Metal ion uptake through complexation or hydrogels can be affected by hydrophilic-hydrophobic balance, the nature of chelate ligands and the extent of cross-linking of macromolecular supports. Ligand function also dictates reactivity, complexation ability and efficiency of polymer supported ligands in the present case expected to be good solution for such problem. This research involves the synthesis and characterization of new polysiloxane surfaces modified with ortho-, meta-, or para-nitrophenyl moieties. The resulting adsorbents have been characterized by SEM, IR, UV, 13C solid state NMR, BET surface area, B.J.H. pore sizes, TGA and nitrogen adsorption-desorption isotherm. These porous materials showed a very good thermal and chemical stability and hence they can be used as perfect adsorbents to uptake toxic heavy metal ions including Cd(II) from groundwater. The concentrations of each adsorbate in the filtrate were determined using Atomic Absorption Spectrophotometer. The results showed that all of the three resulting products had high adsorption efficiency. Also, it showed strong complexation properties with heavy metal ions.

Adsorbent materials are essential in clean-up processes. Research of efficient materials is a well-established technology. In this work, a novel and excellent host for heavy metals was synthesized by covalent immobilization of bipyridine tripodal receptor onto silica particles. The new engineered surface was well analyzed and evaluated by BET, BJH, EA, FT-IR, SEM, TGA and solid-state 13C NMR. The adsorption properties were investigated using Pb(II), Cd(II), Zn(II) and Cu(II) metals by varying all relevant parameters such as pH, contact time, concentration, thermodynamic parameters, kinetics, Langmuir and Freundlich isotherms, etc. The hybrid material has been found to exhibit high distribution coefficients for heavy metals. Adsorption kinetics follows a pseudo-second-order model, as a rapid process as evidenced by equilibrium achieved within 20 min. The resulting adsorption isotherms of the material were better represented by the Langmuir model than the Freundlich model. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) revealed that the adsorption was endothermic and spontaneous. In addition, the proposed material demonstrates a high degree of reusability over a number of cycles, thus enhancing its potential for application in heavy metals recycling. All metal ions were determined by atomic absorption measurements.

A new hybrid material based adsorbent for the efficient elimination of Cu(II) was synthesized by the immobilization of a new conjugated β-ketoenol-bipyridine ligand receptor onto a silica matrix. The analysis of its surface chemistry was evaluated using a set of suitable techniques. Adsorption studies highlight its surface properties for the excellent removal of Cu2+ (131.82 mg g−1) from aqueous solutions using FAAS. The effect of various parameters, such as pH, initial metal concentration, temperature, competitive extraction, thermodynamics and kinetics, on the adsorption of several heavy metals was investigated via metal extraction from real water samples. The adsorption efficiency increases with an increase in pH and follows pseudo-second-order kinetics. Adsorption is rapid, as evidenced by the achievement of equilibrium within 25 min. Adsorption equilibrium data were well fitted to the Langmuir isotherm model and the maximum monolayer adsorption capacity for Cu2+, Zn2+, Cd2+, and Pb2+ was 131.82, 110, 90.75 and 79.71 mg g−1, respectively. The removal of metals onto the new adsorbent is endothermic and spontaneous in nature. The adsorbent presents high selectivity for Cu2+, in competitive mode, compared to other metals and recent literature reports.

A novel and excellent host for heavy metals was synthesized by chemical immobilization of a (E)-4-((pyridin-2-yl-methylene)amino)phenol Schiff base receptor onto silica particles. The new hybrid material (SPSB) was analyzed and evaluated by elemental analysis, FT-IR spectroscopy, solid-state 13C NMR, scanning electron microscopy, BET surface area and BJH analyses. The surface exhibits good thermal stability determined by thermogravimetry and good chemical stability examined in various acidic and buffer solutions (pH 1–7). The coordination ability of SPSB was found to be most efficient in the pH range 6.5–8 for Hg2+, Cd2+, Pb2+ and Zn2+. Alkali coexisting ions did not interfere with separation and determination. The adsorbent can be regenerated at ease without destruction. Heavy metal removal performance (99 mg g−1) was found to be higher compared to previous literature reports.

Two new neutral dimer Cadmium(II) complexes, [Cd2(dmdphphen)2X4] and where X = Cl (complex 1), Br (complex 2), and dmdphphen = 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, were synthesized and characterized by an elemental analysis, UV–Vis, IR, TG/DTA, CV and single crystal X-ray diffraction. Complex 1 crystallizes in the triclinic system with the space group P-1 with unit cell parameters a = 10.1124(8) A, b = 10.8875(8) A, c = 11.5730(9) A, α = 108.323(3)°, β = 107.010(3)°, γ = 91.260(3)° V = 1147.51(15) A3 and Z = 1. The Cd(II) ions are located in a slightly distorted square-pyramidal geometry. The complexes exhibit a quasi-reversible one electron response at −570 mV vs. Cp2Fe/Cp2Fe+, which has been assigned Cd(II)/Cd(III) couples. TG/DTA result shows that these complexes are very stable and decomposed through one step reaction. Calcination of Complex 1, revealed the formation of Cubic nanoparticle CdO.

The inhibitory effect of 1,5-dimethyl-1H-pyrazole-3-carbohydrazide (PyHz) on the corrosion of mild steel in 1 M HCl medium has been examined and characterized using electrochemical impedance spectroscopy (EIS), polarization curves plot (PDP), gravimetrical and SEM/EDX methods. The obtained results indicate that PyHz has a good inhibitory and its inhibition efficiency reaches 96% at 10−3 M. Weight loss and electrochemical techniques results were in reasonable agreement. The inhibitory effect increased with the concentration rise of PyHz but decreased with the increase in temperature. PDP technique suggested that the PyHz acted as a mixed type inhibitor. The adsorption process obeyed the Langmuir isotherm model. Thermodynamic parameters and the scanning electron microscopy analysis were discussed for mild steel in 1 M HCl medium and revealed the adsorption mechanism of PyHz. An electrical equivalent circuit was utilized to analyze EIS data in order to give an adequate model for adsorption process. Surface topography analysis strongly confirmed the electrochemical findings. The adsorption behavior of PyHz on steel surface was also inspected using Density Functional Theory (DFT) method and simulations of Monte Carlo. Quantum chemical calculations and Monte Carlo simulations have confirmed the experimental findings.

Additional file 1: Figure S1. 1H NMR spectrum of 1, Figure S2. 13C NMR spectrum of 1. Figure S3. 13C NMR-DEPTQ-135 spectrum of 1. Figure S4. Mass spectrum of 1. Figure S5. FT-IR spectrum of 1. Figure S6. UV-Vis spectrum of 1.

A simple heterogeneous synthesis of pure adsorbent based polymer hybrid made by condensing a functionalized C,N-bipyrazole with a 3-glycidoxypropyl-trimethoxysilane silylant agent, previously anchored on a silica surface was developed. The formed material (SG2P) was characterized through elemental analysis, FT-IR spectroscopy, (13)C NMR of solid state, scanning electron microscope (SEM), and was studied and evaluated by determination of the surface area using the BET equation, the adsorption and desorption capability using the isotherm of nitrogen and B.J.H. pore sizes. The new material exhibits good thermal stability determined by thermogravimetry curves and good chemical stability was examined in various acidic and buffer solutions (pH 1-7). The binding and adsorption abilities of SG2P were investigated for Hg(2+), Cd(2+), Pb(2+), Zn(2+), K(+), Na(+) and Li(+) cations and compared to the results of classical liquid-liquid extraction with the unbound C,N-bipyrazole compound. The grafting at the surface of silica does not affect complexing properties of the ligand and the SG2P exhibits a high selectivity toward Hg(2+) ion with no complexation being observed towards zinc and alkali metals. The extracted and the complexing cation percentages were determined by atomic absorption measurements.

A novel adsorbent for heavy metals, functionalized with conjugated β-ketoenol Furan, was fabricated using a simple heterogeneous method. The adsorbent design (SiNFn) was well analyzed and characterized by the techniques of solid state 13C NMR, Fourier transform-infrared spectroscopy (FT-IR), elementary analysis, nitrogen adsorption–desorption isotherm, BET surface area, BJH pore sizes, and scanning electron microscopy (SEM). The new surface has good thermal stability determined by thermogravimetry curves analysis (TGA), and a good chemical stability investigated in various acidic and buffer solutions. The effect of various parameters on Cd(II), Cu(II), Zn(II), and Pb(II) adsorption, such as pH, concentration, temperature, competitive extraction, thermodynamics and kinetics studies, and extraction of metals from real water samples were investigated. The results indicated that the adsorption efficiency increases with increasing pH and follows pseudo-second-order kinetics. Adsorption was rapid as evidenced b...