scholarly journals Synthesis, Structural, Density Functional Theory, and X-Ray Diffraction Study of Zn(II) N-Isopropylbenzyldithiocarbamate: Anti-Corrosion Screening in Acid Media

2018 ◽  
Vol 18 (4) ◽  
pp. 755
Author(s):  
Noor Syafiqah Habdul Latif ◽  
Sheikh Ahmad Izaddin Sheikh Mohd Ghazali ◽  
Erna Normaya Abdullah ◽  
Azizul Hakim Lahuri ◽  
Mohammad Fadzlee Ngatiman ◽  
...  
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Density Functional ◽  
Gravimetric Analysis ◽  
Corrosive Media ◽  
Acid Media ◽  
X Ray ◽  
X Ray Crystallography ◽  
Structural Density ◽  
Reflectance Ftir

Corrosion of metal is a serious issue across many industries and is considered costly. Acids used during the cleaning process in industries may contribute to metal erosion. Dithiocarbamate is a ligand that can act as a corrosion inhibitor due to the presence of sulfur and nitrogen as electronegative atoms. Zn(II) N-isopropylbenzyldithiocarbamate (Zn[N-isopbenzdtc]2) complex was synthesized through direct synthetic method of < 4 °C and characterized using Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR), Ultraviolet-Visible (UV-Vis), Nuclear Magnetic Resonance (NMR), X-ray crystallography study, molar conductivity, melting point, and gravimetric analysis. Corrosion inhibition of mild steel was studied for different corrosive media (1 M HCl and 1 M H2SO4). The synthesized inhibitor was studied at different concentrations of 1, 2, 3, 4, and 5 mM at 40 °C. As a conclusion, as the inhibitor concentration decreased, the efficiency of the corrosion inhibitor also decreased at a constant temperature. In this study, it showed that the corrosion activity of mild steel in 1 M H2SO4 was higher compared to 1 M HCl due to the higher concentration of H+, which makes H2SO4 more corrosive than HCl.

Highly Electron-Deficient Pyridinium-Nitrones for Rapid and Tunable Inverse-Electron-Demand Strain-Promoted Alkyne-Nitrone Cycloaddition to Bicyclo[6.1.0]nonyne

2019 ◽  
Author(s):  
Praveen Gunawardene ◽  
Wilson Luo ◽  
Alexander M. Polgar ◽  
John F. Corrigan ◽  
Mark Workentin
Keyword(s):  
Density Functional Theory ◽  
Reaction Kinetics ◽  
Density Functional ◽  
Functional Theory ◽  
X Ray ◽  
Inverse Electron Demand ◽  
X Ray Crystallography ◽  
Electron Demand

<div> <div> <p>Highly accelerated inverse-electron-demand strain-promoted alkyne-nitrone cycloaddition (IED SPANC) between a sta- ble cyclooctyne (bicyclo[6.1.0]nonyne (BCN)) and nitrones delocalized into a Cα-pyridinium functionality is reported, with the most electron-deficient “pyridinium-nitrone” displaying among the most rapid cycloadditions to BCN that is currently reported. Density functional theory (DFT) and X-ray crystallography are explored to rationalize the effects of N- and Cα-substituent modifications at the nitrone on IED SPANC reaction kinetics and the overall rapid reactivity of pyridinium-delocalized nitrones.</p> </div> </div>

How big is big? Separation by conventional methods, X-ray and electronic structures of positional isomers of bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex

2016 ◽  
Vol 20 (01n04) ◽  
pp. 337-351 ◽  
Author(s):  
Derrick R. Anderson ◽  
Pavlo V. Solntsev ◽  
Hannah M. Rhoda ◽  
Victor N. Nemykin
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Positional Isomers ◽  
Excitation Energies ◽  
Functional Theory ◽  
X Ray ◽  
Vertical Excitation ◽  
X Ray Crystallography ◽  
Tddft Calculations ◽  
Insight Into

A presence of bulky 2,6-di-iso-propylphenoxy groups in bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex allows separation of two individual positional isomers and a mixture of the remaining two isomers using conventional chromatography. X-ray structures of “[Formula: see text]” and “[Formula: see text]” isomers were confimed by X-ray crystallography. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations of each individual positional isomer allowed insight into their electronic structures and vertical excitation energies, which were correlated with the experimental UV-vis and MCD spectra.

scholarly journals Calcium D-Pantothenate as Green Corrosion Inhibitor on Mild Steel in 240 ppm NaCl Solution

2019 ◽  
Vol 9 (2S2) ◽  
pp. 435-442
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Potentiodynamic Polarization ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Nacl Solution ◽  
Functional Theory ◽  
Vitamin B5 ◽  
Quantum Chemical Data

Corrosion inhibition of mild steel in 240 ppm NaCl solution using Calcium D-Pantothenate (Vitamin B5 ) as corrosion inhibitor is studied using electrochemical impedance, potentiodynamic polarization and weight loss studies. From the potentiodynamic polarization studies, icorr (corrosion current density) decreases with increasing the concentration of vitamin B5 (VB5 ). The CR (corrosion rate) decreases and the IE (inhibition efficiency) of VB5 increases on increasing the concentration of VB5 .Surface investigation using SEM, EDX spectra, UV-Vis, FTIR, electrochemical impedance, potentiodynamic polarization and adsorption isotherm parameter of VB5 in 240 ppm NaCl solution shows that VB5 can act asworthy corrosion inhibitors. Quantum chemical data obtained from density functional theory (DFT) calculations also agreed with the experimental outcomes.

scholarly journals Synthesis of Chromium(II) Complexes with Chelating Bis(alkoxide) Ligand and Their Reactions with Organoazides and Diazoalkanes

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 273 ◽  
Author(s):  
Sudheer S. Kurup ◽  
Richard J. Staples ◽  
Richard L. Lord ◽  
Stanislav Groysman
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Aryl Azides ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Chromium Vi ◽  
Imido Complexes ◽  
Structure And Bonding

Synthesis of new chromium(II) complexes with chelating bis(alkoxide) ligand [OO]Ph (H2[OO]Ph = [1,1′:4′,1′’-terphenyl]-2,2′’-diylbis(diphenylmethanol)) and their subsequent reactivity in the context of catalytic production of carbodiimides from azides and isocyanides are described. Two different Cr(II) complexes are obtained, as a function of the crystallization solvent: mononuclear Cr[OO]Ph(THF)2 (in toluene/THF, THF = tetrahydrofuran) and dinuclear Cr2([OO]Ph)2 (in CH2Cl2/THF). The electronic structure and bonding in Cr[OO]Ph(THF)2 were probed by density functional theory calculations. Isolated Cr2([OO]Ph)2 undergoes facile reaction with 4-MeC6H4N3, 4-MeOC6H4N3, or 3,5-Me2C6H3N3 to yield diamagnetic Cr(VI) bis(imido) complexes; a structure of Cr[OO]Ph(N(4-MeC6H4))2 was confirmed by X-ray crystallography. The reaction of Cr2([OO]Ph)2 with bulkier azides N3R (MesN3, AdN3) forms paramagnetic products, formulated as Cr[OO]Ph(NR). The attempted formation of a Cr–alkylidene complex (using N2CPh2) instead forms chromium(VI) bis(diphenylmethylenehydrazido) complex Cr[OO]Ph(NNCPh2)2. Catalytic formation of carbodiimides was investigated for the azide/isocyanide mixtures containing various aryl azides and isocyanides. The formation of carbodiimides was found to depend on the nature of organoazide: whereas bulky mesitylazide led to the formation of carbodiimides with all isocyanides, no carbodiimide formation was observed for 3,5-dimethylphenylazide or 4-methylphenylazide. Treatment of Cr2([OO]Ph)2 or H2[OO]Ph with NO+ leads to the formation of [1,2-b]-dihydroindenofluorene, likely obtained via carbocation-mediated cyclization of the ligand.

Corrosion protection performance of titania nanoparticles filled poly(4-methyl-5-vinylthiazole) applied on mild steel in 3.5% sodium chloride solution

2020 ◽  
pp. 875608792093930 ◽  
Author(s):  
I Pugazhenthi ◽  
S Mohammed Ghouse
Keyword(s):  
Mild Steel ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Nano Particles ◽  
Titania Nanoparticles ◽  
X Ray Diffraction ◽  
Corrosive Media ◽  
X Ray ◽  
Polymer Hybrid ◽  
Transmission Electron

Mild steel materials have wide applications in marine construction, because they are low cost, available and easy to handle. However, they have to be protected from corrosive media by coating with polymer hybrid materials. This paper focuses on the anticorrosive properties of poly(4-methyl-5-vinylthiazole) PVTZ coatings on mild steel. Further the coating resistance is enhanced by incorporating Titania Nano particles (TiO2NPs). The nanoparticles were evaluated using X-ray diffraction studies (XRD) and transmission electron microscopy (TEM). PVTZ and its TiO2 nanocomposite were coated on mild steel. Their anticorrosive behavior was analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5% (w/v) NaCl.

scholarly journals Corrosion Inhibition of Mild Steel in Acidic Media by N-[(3,4-Dimethoxyphenyl)Methyleneamino]-4-Hydroxy-Benzamide

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kashmitha Muthamma ◽  
Preethi Kumari ◽  
M. Lavanya ◽  
Suma A. Rao
Keyword(s):  
Dft Calculations ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Surface Characterization ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Low Carbon ◽  
Acid Media

Abstract Mild steel (a low carbon steel) is an affordable engineering material used for many purposes in various environments including mild acidic environment with some precautions. The corrosion behaviour of mild steel (MS) in 0.5 M H2SO4 and 0.5 M HCl, in the temperature range (303–323 K) without and with the inhibitor N-[(3,4-dimethoxyphenyl) methyleneamino]-4-hydroxy-benzamide (DMHB), was investigated using Potentiodynamic polarization and Electrochemical impedance spectroscopy (EIS) techniques supplementing with surface characterization study using scanning electron microscope (SEM) and atomic force spectroscopy (AFM). Experimental observations were found to be in agreement with Density functional theory (DFT) calculations. The inhibition efficiency increases with increase in DMHB concentration and showed maximum inhibition efficiency of 86% in 0.5 M H2SO4 and 81% in 0.5 M HCl, respectively, at concentration of 3 × 10─3 M at 303 K. The inhibition efficiency of DMHB obtained relatively at its lower concentration (3 × 10─3 M) compared to other reported related compounds confirms its potential towards corrosion inhibition. The variation in the kinetic and thermodynamic parameters indicated physisorption of DMHB on MS and its mixed type inhibitive action followed Langmuir’s isotherm model. DFT calculations go along with the experimental results, signifying the potential corrosion inhibition behaviour of DMHB for MS in both the acid media.

Twisted Push - Pull Ethylenes

2008 ◽  
Vol 61 (10) ◽  
pp. 805 ◽  
Author(s):  
Rakesh Naduvile Veedu ◽  
Paul V. Bernhardt ◽  
Rainer Koch ◽  
Curt Wentrup
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Room Temperature ◽  
Dihedral Angles ◽  
Functional Theory ◽  
Activation Barriers ◽  
Rapid Rotation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Calculated Activation

As determined by X-ray crystallography, Meldrum’s acid derivatives 5, 6, and 8 feature dihedral angles around the central C5=C7 double bond of 14–35°, whereas for the anion 9 this angle is 90°. Density functional theory and MP2 calculations are in agreement with the experimental X-ray data for compounds 5–8, but for anion 9 an angle of only ~65° is predicted. It is concluded that a part of the torsion is due to packing forces in the crystal. It is further concluded that these molecules undergo rapid rotation about the central CC bonds at room temperature (calculated activation barriers 5–14 kcal mol–1).

scholarly journals Synthesis, X-Ray Crystallography, Thermal Analysis, and DFT Studies of Ni(II) Complex with 1-Vinylimidazole Ligand

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fatih Şen ◽  
Ramazan Şahin ◽  
Muharrem Dinçer ◽  
Ömer Andaç ◽  
Murat Taş
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Basis Sets ◽  
Mulliken Charge ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Dft Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Density Functional Theory

The paper presents a combined experimental and computational study of hexa(1-vinylimidazole)Ni(II) perchlorate complex. The complex was prepared in the laboratory and crystallized in the monoclinic space group P21/n with a=8.442(5), b=13.686(8), c=16.041(9) Å, α=γ=90, β=96.638(5), and Z=1. The complex has been characterized structurally (by single-crystal X-Ray diffraction) and its molecular structure in the ground state has been calculated using the density functional theory (DFT) methods with 6-31G(d) and LanL2DZ basis sets. Thermal behaviour and stability of the complex were studied by TGA/DTA analyses. Besides, the nonlinear optical effects (NLO), molecular electrostatic potential (MEP), frontier molecular orbitals (FMO), and the Mulliken charge distribution were investigated theoretically.

scholarly journals Emodin Scavenging of Superoxide Radical Includes π–π Interaction. X-Ray Crystal Structure, Hydrodynamic Voltammetry and Theoretical Studies

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 194 ◽  
Author(s):  
Miriam Rossi ◽  
Kelly Wen ◽  
Francesco Caruso ◽  
Stuart Belli
Keyword(s):  
Density Functional ◽  
Superoxide Radical ◽  
Therapeutic Option ◽  
Color Variation ◽  
Stable Complex ◽  
X Ray ◽  
X Ray Crystallography ◽  
Π Stacking ◽  
Vis Spectroscopy ◽  
Voltaic Cell

The naturally occurring anthraquinone emodin is found in many plants that have been part of traditional Chinese medicine (TCM) for thousands of years. Recent pharmacological studies suggest that emodin might be a valuable therapeutic option for the treatment of various diseases. We describe the antioxidant effects of emodin on the superoxide radical. Our techniques include X-ray crystallography, density functional theory (DFT), and a recently developed cyclovoltammetry improvement, the rotating ring-disk electrode (RRDE) method. X-ray results show offset π–π stacking of emodin units in the crystal, and this type of interaction is supported by the DFT, which indicates one superoxide interacting via π–π stacking with the quinone moiety, by transferring one electron to the ring, and inducing some quinone aromatization. The second superoxide seems to form a stable complex after interacting with the H(hydroxyl) in position 3 of emodin. We show that one molecule of emodin sequesters two molecules of superoxide: one forming a complex with H(hydroxyl) in position 3, and the other due to π–π oxidation of superoxide and emodin ring reduction. We conclude that emodin is a very strong antioxidant. Color variation in the voltaic cell was observed during the RRDE study. This was analyzed and explained using a mini-grid gold electrode for UV-Vis spectroscopy in the voltaic cell.

scholarly journals Six-fold C–H borylation of hexa-peri-hexabenzocoronene

2020 ◽  
Vol 16 ◽  
pp. 391-397 ◽  
Author(s):  
Mai Nagase ◽  
Kenta Kato ◽  
Akiko Yagi ◽  
Yasutomo Segawa ◽  
Kenichiro Itami
Keyword(s):  
Density Functional ◽  
Bathochromic Shift ◽  
Density Functional Theory Calculations ◽  
Absorption Bands ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Polycyclic Aromatic ◽  
Direct Functionalization ◽  
Poorly Soluble

Hexa-peri-hexabenzocoronene (HBC) is known to be a poorly soluble polycyclic aromatic hydrocarbon for which direct functionalization methods have been very limited. Herein, the synthesis of hexaborylated HBC from unsubstituted HBC is described. Iridium-catalyzed six-fold C–H borylation of HBC was successfully achieved by screening solvents. The crystal structure of hexaborylated HBC was confirmed via X-ray crystallography. Optoelectronic properties of the thus-obtained hexaborylated HBC were analyzed with the support of density functional theory calculations. The spectra revealed a bathochromic shift of absorption bands compared with unsubstituted HBC under the effect of the σ-donation of boryl groups.

Sign in / Sign up

Export Citation Format

Share Document