F-KCW-Department Publications

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Start date: 2020Subject: search.filters.subject.DFT

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    CHEMINFORMATIC SCRUTINY OF SOME HETEROCYCLIC COMPOUNDS FOR THEIR CORROSION PROTECTIVE CAPABILITY
    (International Journal of Corrosion and Scale Inhibition, 2021-12-27) Ramkumar S; Nalini D; Priyanka D; Qurashi M A; Chauhan D S
    Over the last two decades, molecular modellings are capable of accurately predicting structures, energetics, reactivity, and other properties of molecules. Computational chemistry plays an important role in enabling chemists to: (i) explain and rationalize known chemistry of corrosion inhibitors and (ii) explore new or unknown chemicals applicable as corrosion inhibitors. In contrast to the traditional techniques of identifying and synthesizing new corrosion inhibitors in the wet lab, a prior dry-lab process is suggested by using cheminformatics tools. Once a correlation between the structure and activity or property is found, any number of compounds can be readily screened employing computational methodology. In the present work, the inhibitive performance of three important classes of heterocyclic compounds namely dithiazolidine, thioamidine, and thiourea derivatives have been calculated using quantum chemical methods. The three selected heterocyclic series contains nitrogen and sulphur in their chemical framework that were expected to be the main electron rich centres which act as the adsorption sites on the metal surface. The presence of aromatic ring together with electron donating substituents such as methyl and methoxy were found to enhance the adsorption characteristics of the studied heterocyclic systems. The global reactivity parameters and the local selectivity adsorption centres in each of the studied system were analyzed using theoretical parameters
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    GLYCERAL TRINITRATE: AS POTENTIAL CORROSION PROTECTOR FOR MILD STEEL IN ACID MEDIUM ALONG WITH PAINT-COATED STEEL IN A SALINE ENVIRONMENT
    (Oriental Journal of Chemistry, 2021-12-21) Menaga M; Sowmya, Ramkumar; Nalini D
    The importance of mild steel lies in its industrial applications, and the fight against corrosion is very important from an ecological, economic, technical, and aesthetic view. The current study involves the use of pharmaceutical drugs namely GTN towards corrosion inhibiting reaction was examined by gravimetric and electrochemical approaches. From weight loss studies, maximum I.E (%) 94.04% reached for 60 mg/L concentration of GTN for 6 hrs immersion time. The Polarization measurements showed that the behaviour of GTN as mixed nature and surface assimilation of GTN at the superficial, such that water molecules are substituted at the solution-metal boundary. The corrosion resistance property of the studied inhibitor as coating was also evaluated in NaCl which shows better progress corrosion retardation property of coating in the saline medium. Theoretical calculations were employed using DFT to correlate with the experimental observations.
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    ANTI-CORROSIVE POTENTIAL OF CYPERUS ROTUNDUS AS A VIABLE CORROSION INHIBITOR FOR MILD STEEL IN SULPHURIC ACID
    (Pigment & Resin Technology, 2020-04-17) Rajan, Anitha; Chan, Basha Nusrath Unnisa; Venkatesan, Hemapriya; Selvaraj, Mohana Roopan; Subramanian, Chitra; Ill-Min, Chung; Seung-Hyun, Kim; Prabakaran, Mayakrishnan
    Over the past decade, plant extracts are ultimate green candidatures to substitute the expensive and noxious synthetic corrosion inhibitors. In this regard, this study aims to focus on evaluating anti-corrosion properties of green inhibitor Cyperus rotundus (C. rotundus), a perennial herb found throughout India.The biocompatible components present in C. rotundus extract was analyzed by gas chromatography–mass spectroscopy analysis. The corrosion inhibitory effect of C. rotundus was assessed by impedance, polarization and surface morphometric study [atomic force microscopy (AFM)]. Density functional theory (DFT) study was carried using DFT/B3LYP, and basis set used for calculations was 6-31G (d, p) using Gaussian 03 program package
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    EXPERIMENTAL RESULTS WITH HYPOTHETICAL EVIDENCES FOR BEXOL AS AN EFFECTIVE INHIBITOR ON CORROSION INHIBITION OF MILD STEEL IN ACIDIC ENVIRONMENT AND ITS EPOXY COATING BEHAVIOR
    (Oriental Journal of Chemistry, 2020-06-03) Menaga M; Nalini D; Sowmya, Ramkumar
    The inhibitive ability against mild steel corrosion of pharmacologically active compound Bexol towards acid was valued by gravimetric experiments and electrochemical experiments. The results of the weight loss studies indicated inhibition efficiency was boosted with increased concentration of Bexol from 5 mg/L to 45 mg/L in the acid environment. Potentiodynamic polarization behaviour of the metal specimen in presence of Bexol exposed the mixed style inhibitive action. EIS results established that Bexol adsorb at the metal/acid junction by mere electrostatic physical adsorption mechanism to inhibit the corrosion process. Epoxy coated mild steel without and with the studied bexol was used for electrochemical studies in 3.5% of NaCl for different time intervals. The Density Functional -theory was employed to scrutinize inhibition property of the considered inhibitor. Experimental measurement obtained shows perfect fit to the theoretical calculations
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    GLYCERAL TRINITRATE: AS POTENTIAL CORROSION PROTECTOR FOR MILD STEEL IN ACID MEDIUM ALONG WITH PAINT-COATED STEEL IN A SALINE ENVIRONMENT
    (An International Open Access, 2021-12-21) Menaga M; Sowmya, Ramkumar; Nalini D
    The importance of mild steel lies in its industrial applications, and the fight against corrosion is very important from an ecological, economic, technical, and aesthetic view. The current study involves the use of pharmaceutical drugs namely GTN towards corrosion inhibiting reaction was examined by gravimetric and electrochemical approaches. From weight loss studies, maximum I. E (%) 94.04% reached for 60 mg/L concentration of GTN for 6 h immersion time. The Polarization measurements showed that the behaviour of GTN as mixed nature and surface assimilation of GTN at the superficial, such that water molecules are substituted at the solution-metal boundary. The corrosion resistance property of the studied inhibitor as coating was also evaluated in NaCl which shows better progress corrosion retardation property of coating in the saline medium. Theoretical calculations were employed using DFT to correlate with the experimental observations.
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    A CYANOPYRAN DERIVATIVE FOR PREVENTING CORROSION OF PIPELINE MATERIAL USED IN THE OIL AND GAS INDUSTRY
    (Analytical and Bioanalytical Electrochemistry is an international scientific journal, which is published online every 3 months (since 2009), every 2 months (since 2011) and monthly (since 2018) by Center of Excellence in Electrochemistry, University of Tehran, 2022-09-30) Saranya J; Anusuya N; Benhiba F; Warad I; Abdelkader, M Zarrouk
    The present work deals with the corrosion inhibition mechanism of mild steel in 1 M H2SO4 employing the new carbonitrile derivative viz. 2-amino-4-(4-hydroxyphenyl)-6-(ptolyl)-4H-pyran-3-carbonitrile (HCN). A such mechanism was elicited by means of the potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques and weight loss (WL). The experimental results revealed maximal inhibition efficiency (IE) rates up to 92.4% in weight loss. WL measurement revealed a decrease in corrosion rate with increasing concentration of corrosion inhibitor and decreasing with increasing temperature up to 333 K. The Nyquist curves indicated that the corrosion inhibition was controlled by a charge transfer process whereas the PDP curves showed that the HCN behaved as a mixed-type corrosion inhibitor. The Langmuir isotherm was used to determine the adsorption thermodynamic parameters. Thermodynamic characteristics for activation and adsorption were determined and discussed. Adsorption free energy at 303 K (𝛥𝐺𝑎𝑑𝑠 ° = -22.26 kJ mol-1 for HCN) indicated a combination of chemisorption and physisorption. The inhibitor (HCN) formed a protective layer that acted as a barrier between the surface of the metal and the acid medium which was investigated through surface studies like Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray analysis (EDS). The surface studies were in coincidence with weight loss and electrochemical studies. Density functional theory (DFT) was performed to support the experimental data in an aqueous medium using the basis set 6-311G(d,p). From the Mulliken population analysis, the adsorption sites have been studied and the results of DFT were steady with the experimental studies.
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    A TWO-STEP STRATEGY TO SYNTHESIS NEW AMINOGUANIDINIUM COMPLEXES: CYTOTOXIC EFFECT AND PERSPECTIVES
    (Taylor & Francis, 2022-05-23) Natarajan, Arunadevi; Ponnusamy, Kanchana; Venkatesan, Hemapriya; Mayilsamy, Mehala; Manoharan, Swathika; Ill-Min, Chung; Mayakrishnan, Prabakaran
    The progress of transition metal complexes having anticancer activity has greater influence in cancer therapy. With the anticipation of investigating the anticancer activity and property of the transition metal complexes, Ni(II), Zn(II), and Cd(II) metal complexes of 1-hydroxy-2-naphthoic acid (1H2NA)/2-hydroxy-1-naphthoic acid (2H1NA) with aminoguanidine of ratio 1:1:2 were synthesized and characterized by spectroscopic studies like IR, UV–Vis, Thermal analysis, powder XRD, molar conductivity measurements, antimicrobial, and anticancer studies. Simple salts of 1-hydroxy-2-naphthoic acid (1H2NA)/2-hydroxy-1-naphthoic acid (2H1NA) with aminoguanidine were also prepared in different ratios viz, 1:1 and 1:2. It is characterized by spectroscopic measurements IR, UV, TG-DTA, powder XRD, molar conductivity measurements, and cytotoxic effects were also studied. Nanometal oxides of zinc complexes were prepared and surface morphological studies were investigated. The functional groups were confirmed from IR spectroscopy data. Band gap energies of all the synthesized compounds were calculated from UV–Visible spectroscopy. Various decomposition steps and the thermal stability of the compounds were determined from thermal analysis. From the molar conductivity measurements, it is confirmed that the compounds are electrolytes. SEM and TEM images confirm the rod and hexagonal shape of the respective nanometal oxides. The complexes and nanometal oxides show significant activity against antimicrobials like Staphylococcus aureus, Escherichia coli, and Aspergillus fumigates. The results of present research show that, the synthesized ligands and metal complexes at lower concentration predominantly shows higher cytotoxic activity against cancer cellular lines like MCF-7 and A-549 (human breast cancer cells and human lung cancer cells, respectively). DFT computational studies were carried out using GAUSSIAN 09 W software to understand the bonding mode and chemical parameters of the complexes were calculated using frontier molecular orbital studies.
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    SYNTHESIS, CHARACTERIZATION, THERMAL, THEORETICAL AND ANTIMICROBIAL STUDIES OF SCHIFF BASE LIGAND AND ITS CO(II) AND CU(II) COMPLEXES
    (Journal of Serbian Chemical Society, 2020) Palaniswamy,Venkittapuram Radha Venkitta; Dhandapani, Mahalskshmi; Suyambulingam , Jone Kirubavathy; Subramanian, Chitra
    A Schiff base ligand L was synthesized by condensation of 1,2-diaminoethane with creatinine. The reaction of the ligand with metal chloride salt gives Co(II) and Cu(II) complexes. The synthesized ligand and its metal complexes were characterized by elemental analysis, FT-IR, NMR, UV–Vis, conductivity and magnetic susceptibility measurements as well as thermal analyses. Based on spectral data, tetrahedral geometries have been proposed for the Co(II) and Cu(II) complexes. The molar conductivity data show that the complexes are non-electrolytic in nature. In DFT studies, the geometry of the Schiff base ligand and its Co(II) and Cu(II) complexes were fully optimized using the B3LYP functional together with 6-31g(d,p) and LANL2DZ basis sets. The ligand and its metal complexes were tested against four bacterial species and two fungal species. The results revealed that the metal complexes are more potent against the microbes than the parent ligand.