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Item PRISTINE B40 FULLERENE AS A POTENTIAL GEMCITABINE DRUG CARRIER FOR ANTI-LUNG CANCER PROPERTIES: A DFT AND QTAIM STUDY(Taylor and Francis Ltd, 2024) Sukumar, Abisha Nancy; Duraisamy, Parimala Devi; Paul S, Prince Makarios; Gopalan, Praveena; Angamuthu, AbiramNovel biomedical applications of various nanomaterials are being extensively researched as drug delivery systems. These nanomaterials deliver various anticancer treatments into the specific tumor cell sites, which reduces their terrible side effects. In this study, we have used DFT/B3LYP/6-311++G(d,p) level of theory to examine the efficacy of the pristine B40 fullerene (Boron) as a drug delivery vehicle for gemcitabine an anti-lung cancer medication at various position. From our investigation the most stable adsorption orientation was observed between double bonded oxygen atom of the drug and six membered ring boron atoms of B40 fullerene both in gas and solvent phases. The frontier molecular orbitals and QTAIM studies further support the interaction of gemcitabine medication with the B40 fullerene. NBO and MEP methods show substantial charge transfer from gemcitabine drug molecules to the fullerene. Overall, the results suggest that the B40 fullerene effectively adsorbs the drug and hence can be used as a tool for drug delivery system.Item SYNTHESIS, CHARACTERIZATION, THERMAL, THEORETICAL AND ANTIMICROBIAL STUDIES OF SCHIFF BASE LIGAND AND ITS CO(II) AND CU(II) COMPLEXES (Article)(Serbian Chemical Society, 2020) Palaniswamy, Radha Venkittapuram; Dhandapani, Mahalakshmi; Suyambulingam, Jonekirubavathy; Subramanian, ChitraA 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.Item STRUCTURE AND REACTIVITY OF HALOGENATED GC PNA BASE PAIRS – A DFT APPROACH (Article)(Editorial board of Journal of Experimental Biology and Agricultural Sciences, 2023-11-30) Ranjithkumar, Rajamani; Indumathi, K; Srimathi, P; Praveena, G; Ling, Shing Wong; Sinouvassane, DjearamaneThe present study explored the structural and reactivity relationship of halogenated G-C PNA base pairs using density functional theory (DFT) calculations. The halogens such as F, Cl, and Br are substituted by replacing H atoms involved in H-bonds of the base pairs. All structures were optimized using the B3LYP/6-311++G** theory level, and positive frequencies confirmed their equilibrium states. To understand the structural variations of the considered halogenated systems, the bond distances of R─X, R─H, and X/H•••Y and the bond angles of R─X•••Y were analyzed. The obtained structural parameters and interaction energies are comparable with the previous theoretical reports. In addition, the interaction energies (Eint) and quantum molecular descriptors (QMD) are also calculated to understand the difference between halogenated PNA systems and their non-halogenated counterparts. In this study, the enhancement in the reactivity properties of halogenated PNA systems has been demonstrated, which indicates their improved responsive characteristics in various chemical reactions. Based on the available results, the halogenated PNA systems, carefully considering their substitutional position, facilitate better accommodation for the triplex formation of dsDNA/dsRNA. Therefore, it is concluded that the improved reactivity properties of halogenated PNA base pairs would make them potential candidates for various biological applications.Item SYNTHESIS, STRUCTURAL AND COMPUTATIONAL STUDY, DNA BINDING AND CYTOTOXIC ACTIVITY OF CU(II) COMPLEXES OF 6- AND 7-CHLORO-2-OXO-1,2-DIHYDROQUINOLINE-3-CARBALDEHYDE-2-FUROYL-HYDRAZONES(Elsevier B.V, 2024) Thangavel, Thirunavukkarasu; Hazel A, Sparkes; Valentina, Gandin; Cristina, Marzano; Roberta, Bertani; Mirto, Mozzon; Anna, Scettri; Alberto, Albinati; Francesco, Demartin; Girolamo, Casella; Francesco, Ferrante; Alfonso, Zoleo; Paolo, Sgarbossa; Karuppannan, NatarajanThree new coordination complexes of Cu(II) ions made from two hydrazone ligands, 7-chloro-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-2-furoyl-hydrazone (HL1) and 6-chloro-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-2-furoyl-hydrazone (HL2) have been synthesized and fully characterized by spectroscopic techniques. Their crystal and molecular structures revealed distorted square pyramidal mononuclear complexes: [(L1)Cu(H2O)2](NO3)·3H2O, 1(NO3), [(L2)Cu(H2O)2](NO3)·2H2O·CH3OH, 2(NO3), and [(L2)Cu(NO3)(CH3OH)]·2CH3OH, 3, comprising the ligand (L1 and L2) in tridentate fashion (ONO) with two water molecules in 1+ and 2+, and a single methanol molecule and a nitrate ion in 3 in their respective copper coordination spheres. EPR spectra in frozen methanol revealed the occurrence of several species arising from different coordination environments. A detailed DFT investigation on the energetics of solvents exchange (H2O, MeOH, and DMSO) and simulation of the EPR parameters showed that the exchange processes occur easily in solution. The value gz indicated the occurrence of a dimeric aggregate for 2+. The new copper complexes exhibited a noticeable antiproliferative activity with IC50 values in the micromolar range against HCT-15, H157, BxPC3, PNS-1, and A431 cell lines and they were found to be 3-fold more effective than cisplatin against pancreatic PSN-1 cell lines. Cross-resistance tests on A2780 and LoVo cancer cell lines and the corresponding multidrug or oxaliplatin resistant sublines showed that complexes 1(NO3) and 2(NO3) were equally cytotoxic to sensitive and resistant cells, thus overcoming multidrug and oxaliplatin resistance.Item STRUCTURE AND REACTIVITY OF HALOGENATED GC PNA BASE PAIRS – A DFT APPROACH(Journal of Experimental Biology and Agricultural Sciences, 2023-11-30) Ranjithkumar, Rajamani; Indumathi, K; Srimathi, P; Praveena, G; Ling Shing, Wong; Sinouvassane, DjearamaneThe present study explored the structural and reactivity relationship of halogenated G-C PNA base pairs using density functional theory (DFT) calculations. The halogens such as F, Cl, and Br are substituted by replacing H atoms involved in H-bonds of the base pairs. All structures were optimized using the B3LYP/6-311++G** theory level, and positive frequencies confirmed their equilibrium states. To understand the structural variations of the considered halogenated systems, the bond distances of R─X, R─H, and X/H•••Y and the bond angles of R─X•••Y were analyzed. The obtained structural parameters and interaction energies are comparable with the previous theoretical reports. In addition, the interaction energies (Eint) and quantum molecular descriptors (QMD) are also calculated to understand the difference between halogenated PNA systems and their non-halogenated counterparts. In this study, the enhancement in the reactivity properties of halogenated PNA systems has been demonstrated, which indicates their improved responsive characteristics in various chemical reactions. Based on the available results, the halogenated PNA systems, carefully considering their substitutional position, facilitate better accommodation for the triplex formation of dsDNA/dsRNA. Therefore, it is concluded that the improved reactivity properties of halogenated PNA base pairs would make them potential candidates for various biological applications.Item A TWO-STEP STRATEGY TO SYNTHESIS NEW AMINOGUANIDINIUM COMPLEXES: CYTOTOXIC EFFECT AND PERSPECTIVES(Taylor & Francis Online, 2022-05-30) Natarajan, Arunadevi; Ponnusamy, Kanchana; Venkatesan, Hemapriya; Mayilsamy, Mehala; Manoharan, SwathikaaThe 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.Item A CYANOPYRAN DERIVATIVE FOR PREVENTING CORROSION OF PIPELINE MATERIAL USED IN THE OIL AND GAS INDUSTRY(Analytical & Bioanalytical Electrochemistry, 2022-09-30) Saranya, J; Anusuya, N; Benhiba, F; Warad, I; Abdelkader M, ZarroukThe 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-(p-tolyl)-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 (∆G°ads=-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.Item 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 SOver 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.Item SYNTHESIS, CHARACTERIZATION, THERMAL, THEORETICAL AND ANTIMICROBIAL STUDIES OF SCHIFF BASE LIGAND AND ITS CO(II) AND CU(II) COMPLEXES(Journal of the Serbian Chemical Society, 2020) Venkittapuram, Palaniswamy Radha; Dhandapani, Mahalakshmi; Suyambulingam, Jonekirubavathy; Subramanian, ChitraA 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 forthe 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 theItem EFFECT OF PEPTIDIC BACKBONE ON THE NUCLEIC ACID DIMERIC STRANDS(Taylor & Francis Online, 2020) Indumathi, K; Abiram, A; Praveena, GThis study explores the effect of N-(2-aminoethyl)-glycine peptide chain incorporated at the backbone of nucleic acid dimeric strands on the basis of reactivity descriptors. The structures of obtained PNA dimeric strands were examined through backbone (α, β, γ, δ, ε and ω) and linker (χ1, χ2 and χ3) torsions. The calculated torsions were found to coincide well the available experimental and theoretical data. The peptidic chain incorporated nucleic acid dimers show a drastic change in global reactivity descriptor (gr) values. The vertical ionisation potential (VIP) and polarizability (α′) of peptide chain incorporated Guanine constructs are found to be higher by about 0.24 eV and 98.49 Å3 than their natural counterparts. The obtained gr along with frontier molecular orbitals depict G-containing dimeric strands to have efficient donor and acceptor capability with improved sensitivity upon peptide chain inclusion. This study in general could serve as a basic tool to understand the reactivity properties of PNA modularities, which are the possible building blocks of extended nanostructures.