Inhibition Of Zinc Research Articles

Synthesis, crystal structures and urease inhibition of nickel(II), copper(II), zinc(II) and molybdenum(VI) complexes derived from N,n’-bis(4-bromosalicylidene)-1,3-propanediamine

Three new trinuclear complexes containing either nickel(II), copper(II) or zinc(II), [Ni3L2(NO3)2(CH3OH)2]·2CH3OH (1), [Cu3Br2L2] (2), [Zn3L2(NCS)2(CH3OH)2]·0.5CH3OH·0.5H2O (3), and a new dioxidomolybdenum(VI) complex, [MoO2L] (4), have been prepared from the bis-Schiff base N,N’-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with various metal salts in methanol. The complexes were characterized by elemental analysis, IR and UV–Vis spectra. Molecular structures were confirmed by single crystal X-ray diffraction experiments. The Ni ions in 1 adopt an octahedral coordination environment, bridged by phenolate oxygen and nitrate ligands. The Cu ions in 2 are square pyramidal and square planar, and the Zn ions in 3 are square pyramidal and octahedral. The metal atoms in 2 and 3 are bridged by phenolate oxygen donors. The Mo ion in 4 is octahedral. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N donors. Biological assays revealed that the nickel and copper complexes have effective urease inhibition.

Synthesis, Crystal Structures and Urease Inhibition of Copper(II) and Zinc(II) Complexes Derived from N,N'-Bis(4-bromosalicylidene)-1,3-propanediamine.

A new tetranuclear copper(II) complex [Cu4L2(N3)2(CH3OH)2](NO3)2·4CH3OH (1) and a new trinuclear zinc(II) complex [Zn3L2(CH3COO)2] (2) have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with copper nitrate and zinc acetate, respectively, in the presence of sodium azide. The complexes were characterized by elemental analysis, IR and UV-Vis spectroscopy. Molecular structures of both complexes were confirmed by single crystal X-ray determination. The Cu(II) atoms in complex 1 are bridged by phenolate oxygen atoms and end-on azide ligands. The Zn(II) atoms in complex 2 are bridged by phenolate oxygen atoms and acetate ligands. The Cu(II) atoms in complex 1 are in square planar and square pyramidal coordination. The Zn(II) atoms in complex 2 are in square pyramidal and octahedral coordination. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N atoms. The biological assay reveals that the copper(II) complex has effective urease inhibition.

Synthesis, Crystal Structures and Urease Inhibition of Zinc(II) Complexes Derived from 1-(((2-(pyrrolidin-1-yl)ethyl)imino)methyl)Naphthalen-2-ol

Synthesis, Crystal Structures and Urease Inhibition of Zinc(II) Complexes Derived from 1-(((2-(pyrrolidin-1-yl)ethyl)imino)methyl)Naphthalen-2-ol

Biopolymer and its nanoparticles for surface coating enhancement of epoxy primer on zinc: electrochemical and surface studies

ABSTRACT The purpose of the current work is to develop an eco-friendly formulation which can be successfully utilised to mitigate zinc corrosion in marine environments. Biopolymer amylopectin and its nanoparticles were used to improve the coating characteristics of epoxy primer on zinc. Amylopectin nanoparticles (AMP-Np) were prepared by the microwave-assisted nanoprecipitation method and characterised using XRD, ATR-FTIR, and TEM studies. Inhibition studies were performed to achieve the optimum inhibitor concentration required for corrosion inhibition of zinc in 3.5% NaCl. Detailed surface morphology was studied using scanning electron microscopy and atomic force microscopic techniques. The overall efficiency of the coating after incorporating AMP (0.02 gL−1) was found to be 99.5%. With the addition of AMP-Np (0.005 gL−1), 99.9% coating efficiency was attained by reducing the concentration to 1/4th of AMP. The epoxy-coated metal coupons, along with micro and nano AMP, were dipped in 3.5% NaCl for 15 days to mitigate corrosion of zinc.

Synthesis, Crystal Structures and Urease Inhibition of Zinc(II) and Copper(II) Complexes Derived from 2-Amino-N′-(1-(Pyridin-2-yl) Ethylidene)Benzohydrazide

Synthesis, Crystal Structures and Urease Inhibition of Zinc(II) and Copper(II) Complexes Derived from 2-Amino-N′-(1-(Pyridin-2-yl) Ethylidene)Benzohydrazide

A study on use of Telmisartan drug for corrosion inhibition of zinc in 0.1M hydrochloric acid: Surface characterization and Quantum studies

Corrosion inhibition property of Telmisartan on zinc in 0.1 M HCl medium was investigated by chemical and electrochemical techniques. Inhibition action of Telmisartan was found to be increased with increase in concentration and decreased with raise in temperature. Maximum inhibition efficiency of 77% was observed at 20 ppm inhibitor concentration. Inhibition action of inhibitor is due to adsorption on zinc metal surface and it follows the Langmuir adsorption isotherm. Influence of temperature on inhibition action of Telmisartan was studied through activation parameters. Surface morphology of zinc surface with and without inhibitor was examined through SEM and EDX. Surface roughness was studied by AFM and contact angle measurement techniques. FTIR spectral studies confirmed the protecting nature of Telmisartan on zinc corrosion. Quantum chemical data were calculated to prove its suitability as a corrosion inhibitor and to describe the effective adsorption of Telmisartan molecule.

Synthesis, Characterization, Crystal Structures, and Urease Inhibition of Copper(II) and Zinc(II) Complexes Derived from Benzohydrazones

A new copper(II) complex [Cu(L1)(NCS)(CH3OH)] (1) and a new zinc(II) complex [ZnCl2(HL2)]·CH3OH (2), derived from 4-bromo-N'-(pyridin-2-ylmethylene)benzohydrazide (HL1) and 4-methoxy-N'-(pyridin-2-ylmethylene)benzohydrazide (HL2), were prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction. The hydrazone HL1 coordinates to the Cu atom in enolate form, while the hydrazone HL2 coordinates to the Zn atom in carbonyl form. Single crystal structural analyses indicate that the hydrazones coordinate to the metal atoms through the pyridine N, imino N, and enolate/carbonyl O atoms. The Cu atom in complex 1 is in square pyramidal coordination, and the Zn atom in complex 2 is in trigonal-bipyramidal coordination. The inhibitory effects of the complexes on Jack bean urease were studied, which show that the copper complex has strong activity on urease.

Corrosion inhibition of zinc in 0.1 M hydrochloric acid medium with clotrimazole: Experimental, theoretical and quantum studies

Clotrimazole an antifungal drug was investigated for its corrosion inhibition action on zinc metal in 0.1 M HCl solution. Corrosion rate was determined by weight loss, potentiodynamic polarization and impedance spectroscopic techniques. Electrochemical methods (EIS and polarization) have reported inhibition efficiency of up to 90% for 500 ppm concentration of clotrimazole. Data obtained from both chemical and electrochemical studies showed that the corrosion rate of Zn decreased with increase in inhibitor concentration and also with temperature. Tafel polarization measurements showed that clotrimazole acts as mixed type of corrosion inhibitor and its adsorption on the zinc surface obeys Langmuir isotherm. Thermodynamic activation and quantum chemical parameters were calculated and discussed to describe the mechanism of adsorption. These results were supported by FTIR spectral study of corrosion product formed on the zinc surface in the presence of clotrimazole. Contact angle measurements show increased hydrophobicity of zinc surface, while SEM images of zinc surface confirmed considerable decrease of surface inhomogenities in the presence of clotrimazole.

Corrosion inhibition of zinc in aqueous acidic media using a novel synthesized Schiff base – an experimental and theoretical study

The kinetics of H2 production during Zn corrosion in 0.5 M HCl without and with various additives of N,N'-bis-(1-hydroxyphenylimine)-2,5-thiophenedicarboxaldehyde (HPTD) was studied using gasometry and electrochemical techniques. The surface of the corroded Zn samples was investigated using SEM and Optical Profilometry. The rate of H2 production (RHP) increased with the immersion time and temperature. Presence of HPTD mitigated RHP due to an adsorption process. The electrochemical impedance spectroscopy showed that HPTD had a good inhibitive effect. Polarization data proved that HPTD acted as a surface-active mixed-type inhibitor. Some thermodynamic parameters were deduced and discussed. Theoretical calculations were also conducted to corroborate the capability of HPTD to protect Zn surface from corrosion process.

Corrosion Inhibition of Zinc in Acid Medium using some Novel Organic Compounds

Corrosion Inhibition of Zinc in Acid Medium using some Novel Organic Compounds

Corrosion inhibition of zinc in sodium sulphate solution using nonionic surfactants of tween series: Experimental and theoretical study

The effects of three tween compounds have been tested as corrosion inhibitors of a zinc surface in 0.1M of sodium sulphate (Na2SO4) using potentiodynamic, potentiostatic transient in addition to the Electrochemical Impedance Spectroscopy (EIS) method. The efficiency of the inhibitory effect of these additives was found to decrease in the order: Tween-60>Tween-80>Tween-20. These compounds were selected based on their active surface property and high molecular weight as well as their solubility in aqueous media. Cyclic voltammetry (CV) was used to evaluate their effect on the ethanol oxidation. The experimental results were discussed and the correlation between the outcomes and inhibition properties towards Zn pitting corrosion was accomplished. Finally, quantum chemical descriptors of the tween derivatives that relate to their performance as regards corrosion inhibition efficiency have been determined and found to be in good agreement with the experimental results.

Synergistic Effect of Halide Ions on the Corrosion Inhibition of Zinc in Hydrochloric Acid using Schiff base compound, 1-phenyl-2, 3-dimethyl-4-(benzylamino)pyrazole-5-one

The inhibitive effect of1-phenyl-2,3-dimethyl-4-(benzylamino) pyrazole-5-one (PD(B)PO) on zinc corrosion in 0.1 M hydrochloric acid solution was studied using gravimetric method. The influence of halides viz., KCl, KBr and KI on the corrosion inhibition of PD(B)PO were also investigated. Results show that PD(B)PO alone provided satisfactory inhibition on the corrosion of zinc and it was also found that the inhibition efficiency increased synergistically in the presence of halide ions. The synergistic effect of halide ions was found to follow the order: KI > KBr > KCl. The inhibitor reduced the corrosion rate through adsorption process and obeyed the Freundlich adsorption isotherm.

Effects of root addition and foliar application of nitric oxide and salicylic acid in alleviating iron deficiency induced chlorosis of peanut seedlings

ABSTRACTNitric oxide (NO) and salicylic acid (SA) are two important signaling molecules, which could alleviate chlorosis of peanut under iron (Fe) deficiency. Here, we further investigated the mechanism of different combinations of sodium nitroprusside (SNP, a nitric oxide donor) and SA supplying in alleviation Fe deficiency symptoms and selected which is the best combination. Thus, peanut was cultivated in hydroponic culture under iron limiting condition with different combinations of SNP and SA application. After 21 days, Fe deficiency significantly inhibited peanut growth, decreased soluble Fe concentration and chlorophyll contents, and disturbed ionic homeostasis. In addition, the content of reactive oxygen species (ROS) and malondialdehyde (MDA) concentration increased, which led the lipid peroxidation. Application of SNP and SA significantly changed Fe trafficking in cells and organs, which increased Fe uptake from nutrient solution, and transport from root to shoot, enhanced the activity of ferric-chelate reductase (FCR), that increased the available Fe in cell organelles, and the active Fe, chlorophyll contents in leaves. Furthermore, ameliorated the inhibition of calcium (Ca), magnesium (Mg) and zinc (Zn) uptake and promoted plant growth in Fe deficiency. At the same time, it increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) to protect the plasmolemma from peroxidation. Results demonstrated that different combinations of SNP and SA application could alleviate the chlorosis of peanut in Fe deficiency by various mechanisms. Such as increased the available Fe and chlorophyll concentrations in leaves, improved the activities of antioxidant enzymes and modulated the mineral elements balance and so on. Foliar application of SNP and SA is the best to protect leaves while directly adding them into nutrient solution is the best to protect roots. These results also indicated that the effects of SNP and SA supplying together to leaves or roots are better than respectively adding to roots and spraying to leaves. The best combination is foliar application of SNP and SA.

Tricine [N-(Tri(hydroxymethyl)methyl)glycine] – A novel green inhibitor for the corrosion inhibition of zinc in neutral aerated sodium chloride solution

Corrosion and corrosion inhibition of zinc electrode were investigated in neutral chloride solution using electrochemical techniques. Increasing chloride concentration leads to an increase in the corrosion rate of the electrode. The corrosion inhibition characteristics of Tricine (N-(Tri(hydroxymethyl)methyl)glycine) have been studied as an eco-friendly green inhibitor for corrosion control of zinc electrode in 0.5M NaCl corrosive solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Tricine provided an inhibition efficiency of 86.7% at 3mM which increased to about 90% with 10mM. The corrosion inhibition mechanism of the protective layers is also discussed. The adsorption of Tricine on metal surface obeyed Langmuir’s adsorption isotherm. Polarization measurements showed that the Tricine acted as anodic inhibitor in NaCl solution and the inhibitor molecules followed physical adsorption on the surface of zinc.

Novel Fluorinated 8-Hydroxyquinoline Based Metal Ionophores for Exploring the Metal Hypothesis of Alzheimer's Disease.

Zinc, copper, and iron ions are involved in amyloid-beta (Aβ) deposition and stabilization in Alzheimer's disease (AD). Consequently, metal binding agents that prevent metal-Aβ interaction and lead to the dissolution of Aβ deposits have become well sought therapeutic and diagnostic targets. However, direct intervention between diseases and metal abnormalities has been challenging and is partially attributed to the lack of a suitable agent to determine and modify metal concentration and distribution in vivo. In the search of metal ionophores, we have identified several promising chemical entities by strategic fluorination of 8-hydroxyquinoline drugs, clioquinol, and PBT2. Compounds 15-17 and 28-30 showed exceptional metal ionophore ability (6-40-fold increase of copper uptake and >2-fold increase of zinc uptake) and inhibition of zinc induced Aβ oligomerization (EC50s < ∼5 μM). These compounds are suitable for further development as drug candidates and/or positron emission tomography (PET) biomarkers if radiolabeled with (18)F.

Inhibition Effect of an Anti-HIV Drug on the Corrosion of Zinc in Acidic Medium

Corrosion inhibition of zinc in 0.1 M HCl by Tenofovir Disproxil Fumarate (TDF) an anti-HIV drug has been investigated by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy. The experimental results suggested the inhibition efficiency increases with the increase in inhibitor concentration up to 10 ppm. Polarization results revealed that TDF acts as a mixed type inhibitor. The effect of temperature on the corrosion behavior of zinc in the given temperature range from 303–333 K was studied. Adsorption of the inhibitor followed the Langmuir isotherm. Activation and thermodynamic adsorption parameters were calculated and discussed.

Corrosion Inhibition of C38 Steel in 1M HCl Media By Amazonian Tree Alkaloidic Extract: Electrochemical and Phytochemical Study of Xylopia Frutescens Aubl

The present report continues to focus on the broadening application of plant extracts for metallic corrosion control [1and 2] and reports on the inhibiting effect of the Xylopia frutescens alkaloidic extract on the corrosion of C38 steel in 1 M hydrochloric acid. This extract presents mainly aporphinoid alkaloids, with nitrogen, oxygen, and aromatic rings. The corrosion inhibition’s is studied by polarization curves and electrochemical impedance spectroscopy (EIS). Constant phase element parameters of EIS are graphically calculated for better data precision. Studies on the phytochemical constituents of the total extract were also established and the active(s) molecule(s) are identified by NMR spectroscopy.The total alkaloid extract of Xylopia frutescenswas found to be an inhibitor for C38 steel corrosion in 1 M HCl solution and its inhibition efficiency increased with increasing concentration. The study showed that the inhibition behavior of the crude extract is due to the presence of aporphinoid alkaloids in the crude extract.1- F.Suedile,etal., Corrosion inhibition of zinc by Mansoa alliacea plant extract in sodium chloride media: Extraction, Characterization and Electrochemical Studies, Electrochim. Acta (2014), http://dx.doi.org/10.1016/j.electacta.2013.12.0702- M. Chevalier, et al., Enhanced corrosion resistance of mild steel in 1 M hydrochloric acid solution by alkaloids extract from Aniba rosaeodora plant: Electrochemical, phytochemical and XPS studies, Electrochim. Acta (2013), http://dx.doi.org/10.1016/j.electacta.2013.12.023

Electrochemical Adsorption Properties and Inhibition of Zinc Corrosion by Two Chromones in Sulfuric Acid Solutions

The electrochemical behavior and corrosion inhibition of zinc in 0.5 M H2SO4 in the absence and presence of some chromones has been investigated using weight loss, potentiodynamic polarization, electrochemical impedance spectros- copy (EIS) and electrochemical frequency modulation (EFM) techniques. The presence of these investigated compounds in the corrosive solutions decrease the weight loss, the corrosion current density, and double layer capacitance but increases the charge transfer resistance. Polarization studies were carried out at room temperature, and showed that all the studied com- pounds act as mixed type inhibitors with a slight predominance of cathodic character. The effect of temperature on corrosion inhibition has been studied and the thermodynamic activation and adsorption parameters were determined and discussed. The adsorption of the investigated compounds on zinc was found to obey Langmuir adsorption isotherm.

Synthesis, characterization, crystal structures, enzyme inhibition, DNA binding, and electrochemical studies of zinc(II) complexes

Five zinc(II) complexes, [Zn(L1)2] (1), [Zn(L1)2(phen)H2O]·H2O (2), [Zn(L1)2(bipy)] (3), [Zn(L2)2] (4), and [Zn(L2)2(phen)] (5) (where L1 = 4-nitrophenylacetate, L2 = phenylacetate, phen = 1,10-phenanthroline and bipy = 2,2′-bipyridine), have been synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR. Complexes 2, 3, and 4 have been confirmed by single-crystal X-ray diffraction. In 2 and 3, zinc is bonded monodentate to two carboxylates exhibiting distorted trigonal bipyramidal and tetrahedral geometries, respectively, whereas in 4, the carboxylates are bridging bidentate in distorted tetrahedral geometry. The complexes have been screened for electro- and biological activities, including DNA interaction and enzyme inhibition studies. The effect of concentration of 1–5 on the activity of enzyme, alkaline phosphatase, showed that an increase in concentration of complex decreased the activity of the enzyme. Electrochemical behavior of HL1, 2, and 3 was investigated by cyclic voltammetry and it was observed that ligand-centered electro-activity exhibits a proportionate change on complexation. The UV–visible spectroscopic and viscometric data indicate electrostatic and groove binding of the complexes with DNA. The binding constant and Gibb’s free energy values indicate the feasibility of the complex–DNA interaction and show potent biological activity of the complexes.

Corrosion Inhibition of Zinc by Aqueous Vanadate Species

This study presents a characterization of the degree and mechanism of corrosion inhibition of Zn by vanadate inhibitors. A combination of open circuit potential measurements, anodic and cathodic polarization, and Raman spectroscopy were used to compare corrosion inhibition of Zn exposed to or pre-treated with a dilute ∼pH 6.3 NaVO3+NaCl solution, which likely contained predominantly tetrahedrally coordinated vanadate species, relative to controls. The presence of vanadate caused a decrease in corrosion current density of up to two orders of magnitude due to overall mixed anodic and cathodic inhibition associated with the formation and/or stabilization of adherent surface films.