Yazar "Kurup, M. R. Prathapachandra" seçeneğine göre listele

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    Copper(II) chelates derived from an N,N,O-tridentate 2-pyridinecarboxaldehyde-N 4 -phenylsemicarbazone: Synthesis, spectral aspects, crystal structure, FMO and NBO analysis
    (2023) Sithambaresan, M.; Kurup, M. R. Prathapachandra; Serdaroğlu, Goncagül; Kaya,Savaş
    Seven novel Cu(II) complexes [Cu(HPySc)Cl 2 ] ( 1 ), [Cu 2 (PySc) 2 (NO 3 ) 2 ] ·H 2 O ( 2 ), [Cu(HPySc)(SO 4 )] ·½H 2 O ( 3 ), [Cu 2 (PySc) 2 (OAc) 2 ] ·CH 3 OH ( 4 ), [Cu 2 (PySc) 2 Br 2 ] ·H 2 O ( 5 ), [Cu(PySc)(NCS)] ·2H 2 O ( 6 ) and [Cu 2 (PySc) 2 (N 3 ) 2 ] ( 7 ) with 2-pyridinecarboxaldehyde-N 4 -phenylsemicarbazone (HPySc) have been prepared and character- ized using different analytical and spectroscopic techniques. The complex 6 is expected to be square planar while the other complexes are expected to be square pyramidal arrangement, among these, the geometry of complex 4 has been conformed by single crystal XRD study that it is a dimer and adopts distorted square pyramidal geometry around copper(II) centre. All the complexes are found to be para- magnetic and non-conductive in nature. The semicarbazone ligand is coordinated in neutral form in two of the complexes and in ionic form in others. DFT/B3LYP/6-311g ∗∗/LANL2DZ computations of the ligand HpySc (PyCHNNCONHPh) and seven Cu(II) complexes were performed to analyze the FMOs and impor- tant electron delocalizations that existed in each compound. Molecular stability and bond strengths have been investigated by applying natural bond orbital (NBO) analysis. All the complexes are more stable than the semicarbazone and the complex 2 is the most electronically stable (-5.160 eV) among the com- plexes. Furthermore, the semicarbazone is the hardest and complex 5 is the softest than all complexes due to the ηvalues. The calculated energy gap between HOMO and LUMO energies show the variations of nucleophilic and electrophilic reactivity regions in the semicarbazone and in complexes 1-7 .
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    Diversities in the chelation of aroylhydrazones towards cobalt(II) salts: Synthesis, spectral characterization, crystal structure and some theoretical studies
    (Elsevier, 2021) Mangalam, Neema Ani; Kurup, M. R. Prathapachandra; Suresh, Eringathodi; Kaya, Savas; Serdaro, Goncagul
    Five cobalt complexes synthesized from two aroylhydrazones were characterized by elemental analyses, thermogravimetric analysis, molar conductivity, magnetic susceptibility measurements, IR and electronic spectra. Single crystal X-ray structure of one of the complex is also reported and it got crystallized in triclinic space group P (1) over bar and the crystal structure shows a distorted octahedral geometry around the metal center. Spectral data reveal that both the aroylhydrazones are tridentate and coordinate through the azomethine nitrogen, hydrazonic oxygen, and pyridyl nitrogen. Magnetic susceptibility measurements confirm the paramagnetic nature of the Co(II) complexes and one of the complex was found to be diamagnetic in nature. Additionally, HF/6-311G(d,p)/LANL2DZ calculations were performed to predict the possible intramolecular interactions contributing to the lowering of the stabilization energy. Accordingly, pi -> pi* transitions were found to be responsible for the stabilization energy for the ligands and their cobalt complexes. To describe and discuss the chemical reactivity and stability of synthesized complexes, quantum chemical parameters like frontier orbital energies, hardness, softness, energy gap, electronegativity, chemical potential, electrophilicity, polarizability and dipole moment were calculated. Also, the main electronic structure principles such as maximum hardness, minimum polarizability, and minimum electrophilicity principles were considered to evaluate the stability of the complexes. (C) 2021 Elsevier B.V. All rights reserved.
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    Metal Complexes of a Thiosemicarbazone with Heterocyclic Bases as Coligands: Spectral Characterization, Crystal Structures, DFT and In silico Docking Studies
    (Springer/Plenum Publishers, 2024) Mathews, Nimya Ann; Sithambaresan, M.; Kaya, Savas; Chtita, Samir; Kurup, M. R. Prathapachandra
    Copper(II) and zinc(II) complexes, [Cu(esct)(4-pico)] (1), [Zn(esct)(5,5 '-dmbipy)]center dot H2O (2), [Cu(esct)(5,5 '-dmbipy)] (3), (where H(2)esct = 3-ethoxysalicylaldehye-N4-cyclohexylthiosemicarbazone) were synthesized by reacting copper acetate/zinc acetate with the thiosemicarbazone derivative (H(2)esct) along with heterocyclic bases. The thiosemicarbazone forms doubly deprotonated anions in all the complexes to coordinate via thiolate S, azomethine N and phenolate O atoms. The complexes were characterized by various spectroscopic techniques like infrared, UV-vis, 1H NMR and EPR spectra. The single crystal XRD studies confirmed the structures. All the three complexes got crystallized in triclinic space group P (1) over bar Complexes are found to have four, five and six coordination around the metal center. The importance of van der Waals interactions in them is explained by Hirshfeld surface analysis. We have used Density Functional Theory (DFT) methods and optimized ground states of the studied complexes using the Gaussian 09 package. Electrostatic potential plots of complexes were investigated. Further, docking studies were carried out with various Epidermal Growth Factor Receptor (EGFR) enzymes. [GRAPHICS] .
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    Mixed ligand copper(II) chelates derived from an O, N, S- donor tridentate thiosemicarbazone: Synthesis, spectral aspects, FMO, and NBO analysis
    (Pergamon-Elsevier Science Ltd, 2020) Jacob, Jinsa Mary; Kurup, M. R. Prathapachandra; Nisha, K.; Serdaroglu, Goncagul; Kaya, Savas
    Five new copper(II) chelates [(Cu(bmct))(2)] (1), [Cu(bmct)(phen)] (2), [Cu(bmct)(bipy)] (3), [Cu(bmct)(4,4'-dmbipy)] (4) and [Cu(bmct)(5,5'-dmbipy)] (5) with 5-bromo-3-methoxysalicylaldehyde-N(4)-cyclohexylthiosemicarbazone (H(2)bmct) as the chelating ligand and 1,10-phenanthroline, 2,2'-bipyridine, 4,4'-dimethylbipyridine, 5,5'-dimethylbipyridine as coligands have been synthesized and characterized by different physicochemical techniques like CHNS analysis, molar conductivity and magnetic studies, IR, UV/Vis and EPR spectral studies. In all the complexes, the thiosemicarbazone exists in thioiminolate form and coordinates to the metal through azomethine nitrogen, thioiminolate sulfur, and phenolate oxygen. EPR spectra in polycrystalline state at 298 K showed that compounds 1, 4, and 5 are isotropic, 2 is axial and 3 is rhombic in nature. In DMF at 77 K, compound 1 showed hyperfine lines in the parallel and perpendicular regions as well as superhyperfine lines due to the interaction of copper center with azomethine nitrogen of the ligand. Complex 2, in which g(parallel to)>g(perpendicular to)> 2.0023 suggests a distorted square pyramidal structure. To analyze the stability of the complexes, quantum chemical parameters like hardness, softness, polarizability, electrophilicity, electronegativity, and dipole moment were calculated and discussed within the framework of electronic structure principles known as Maximum Hardness, Minimum Polarizability and Minimum Electrophilicity Principles. Besides, the intramolecular donor-acceptor interactions for all complexes were evaluated by using NBO analysis. All calculations proved that Compound 3 is the most stable chelate among them. (C) 2020 Elsevier Ltd. All rights reserved.
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    Mononuclear and binuclear dioxidomolybdenum(VI) chelates derived from a tridentate ONO donor aroylhydrazone: Spectral, structural, DFT and in silico biological investigations
    (Pergamon-Elsevier Science Ltd, 2024) Aravindakshan, A. Ambili; Mohan, Nithya; Kurup, M. R. Prathapachandra; Erkan, Sultan; Manoj, E.
    Four dioxidomolybdenum(VI) complexes, [MoO2(L)]2 & sdot;H2O (1), [MoO2(L)(py)] (2), [MoO2(L)(3-pic)]& sdot;H2O (3) and [MoO2(L)(4-pic)] (4) of a dibasic tridentate ONO donor aroylhydrazone, H2L (where H2L = 3-methoxy-2hydroxybenzaldehyde-2-furoic acid hydrazone) have been synthesized and well characterized. The stoichiometric reaction of aroylhydrazone with MoO2(acac)2 in methanolic medium yielded phenoxobridged binuclear complex 1 whereas monomeric complexes, 2, 3 and 4 were formed as a result of incorporating different monodentate heterocyclic bases. The tridentate aroylhydrazone coordinates to the MoO22+ core through phenolate oxygen, azomethine nitrogen and iminolate oxygen atoms. Single crystal XRD studies established the coordination geometry of mononuclear dioxidomolybdenum(VI) complexes as distorted octahedron. The crystal structures and various solid state interactions were also investigated here. DFT investigations were conducted to explore the reactivity parameters of the studied aroylhydrazone and complexes. Furthermore, molecular docking analyses unveiled the superior putative binding energy of the investigated compounds in contrast to cisplatin. These findings were particularly pronounced in relation to the selected target proteins, which are indicative of their potential efficacy against lung and breast cancer cell lines.
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    Spectral studies and quantum chemical ab initio calculations for Copper(II) complexes of two heterocyclic aroylhydrazones
    (Elsevier, 2021) Sheeja, S. R.; Mangalam, Neema Ani; Sithambaresan, M.; Kurup, M. R. Prathapachandra; Kaya, Savas; Serdaroglu, Goncagul
    In the present study, five copper(II) complexes of quinoline-2-carbaldehyde benzoylhydrazone and a copper(II) complex of 2-benzoylpyridine benzoylhydrazone were synthesized. From the elemental analyses, conductivity measurements and by the determination of magnetic moments, the complexes were formulated. The complexes were characterized by IR, electronic and EPR spectroscopy. From the trend in g values, considerable covalent character is expected to the metal-ligand bonds and also, square pyramidal geometry is suggested for five coordinated complexes. Half field signals observed in the EPR spectra of [Cu(QCB)N-3](2)center dot H2O and [Cu-2(BPB)(2)(mu-SO4)], in solid state at 298 K and in frozen solution, confirm the dimeric structure for the complexes. The quantum chemical results obtained from the ab initio calculations for the aroylhydrazones and their Cu(II)- complexes were evaluated to explain the observed reactivity tendency of the compounds. (C) 2021 Elsevier B.V. All rights reserved.
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    Spectral, thermal and DFT studies of novel nickel(II) complexes of 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a square planar azido-nickel(II) complex
    (Elsevier, 2022) Jayakumar, K.; Seena, E. B.; Kurup, M. R. Prathapachandra; Kayac, Savas; Serdaroglu, Goncagul; Suresh, E.; Marzouki, Riadh
    Novel six Ni(II) complexes of an NNS donor 2-benzoylpyridine-N-4-methyl-3-thiosemicarbazone(HL) are synthesized and characterized. Various physicochemical techniques are applied for the study of the co-ordination behavior of the thiosemicarbazone to the nickel center. In all the complexes, thiosemicarbazone is coordinated in the thiolate form. A four coordinated Ni(II) complex [NiLN3] is crystallized and its molecular and crystal structures are determined by single-crystal X-ray crystallography. Single-crystal XRD reveals that the complex got crystallized in the monoclinic space group P2(1)/n and nickel(II) has a square planar environment. Intramolecular hydrogen bonding interactions make the complex more rigid and in the crystal lattice, the intermolecular hydrogen bonding interactions generate a supramolecular 1 D chain. The chemical reactivity behavior of the HL and six Ni(II) complexes was evaluated with the CAM-B3LYP quantum chemical calculations. The validity of electronic structure principles like Maximum Hardness, Minimum Polarizability, and Minimum Electrophilicity Principle in the study is discussed. (C) 2021 Elsevier B.V. All rights reserved.
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    Spectroscopic, crystal structure and DFT-assisted studies of some nickel(II) chelates of a heterocyclic-based NNO donor aroylhydrazone: in vitro DNA binding and docking studies
    (Springer, 2024) Nair, Yamuna; Joy, Francis; Vinod, T. P.; Vineetha, M. C.; Kurup, M. R. Prathapachandra; Kaya, Savas; Serdaroglu, Goncaguel
    Five new nickel(II) complexes have been synthesised with an NNO donor tridentate aroylhydrazone (HFPB) employing the chloride, nitrate, acetate and perchlorate salts, and all the complexes are physiochemically characterized. Elemental analyses suggested stoichiometries as Ni(FPB)(NO3)]& BULL;2H(2)O (1), [Ni(HFPB)(FPB)]Cl (2), [Ni(FPB)(OAc)(DMF)] (3), [Ni(FPB)(ClO4)]& BULL;DMF (4), [Ni(FPB)(2)] (5). Aroylhydrazone is found coordinating in deprotonated iminolate form in four of the complexes (1, 3, 4, 5) however in one case (complex 2), two aroylhydrazone moieties are binding to the metal centre in the neutral and anionic forms. The structure of the bisligated complex 5, found using single crystal X ray diffraction studies confirmed that the metal has a distorted octahedral N4O2 coordination environment, with each of the two deprotonated ligands coordinating through the pyridine nitrogen, imino-hydrazone nitrogen and the enolate oxygen of the hydrazone moiety. To compare and study, the electronic interactions and stabilities of the metal complexes, various quantum chemical parameters were calculated. Moreover, Hirshfeld surface analysis was carried out for complex 5 to determine the intermolecular interactions. The biophysical attributes of the ligand and complex 5 have been investigated with CT-DNA and experimental outcomes show that the Ni(II) complex exhibited higher binding propensity towards DNA as compared to ligand. Furthermore, to specifically understand the type of interactions of the metal complexes with DNA, molecular docking studies were effectuated. In addition, the electronic and related reactivity behaviors of the ligand and five Ni(II) complexes were studied using B3LYP/6-31 + + G**/LANL2DZ level. As expected, the obtained results from Natural Bond Orbital (NBO) computations displayed that the resonance interactions (n -> pi* and pi -> pi*) play a determinant role in evaluating the chemical attributes of the reported compounds.