996-98-5Relevant articles and documents
Synthesis and characterization of [Mn(phen)(H2O)4]·SO4·2H2O
Syiemlieh, Ibanphylla,Kumar, Arvind,Kurbah, Sunshine D.,Lal, Ram A.
, p. 102 - 109 (2018)
Manganese(II) complex [Mn(phen)(H2O)4]·SO4·2H2O has been synthesized in aqueous methanol medium. The complex crystal was directly obtained from reaction of MnSO4·H2O in water with a mixture of methanol solution of disalicyaldehyde oxaloyldihydrazone and 1,10-phenanthroline. Its structure has been established by X-ray crystallography. It has also been characterized by thermogravimetry, TEM, magnetic moment, UV–visible, EPR and IR spectra. The complex is normal paramagnetic and shows a weak d-d band at 420 nm due to 6A1g (F) → 4T2g (G) transition and strong charge transfer bands. The EPR spectrum of the complex is indicative of decrease of metal-metal interaction with decrease in temperature. IR spectra of the complex is consistent with the coordination of 1,10-phenanthroline to the manganese(II) centre.
Synthesis, characterization and structure assessment of mononuclear and binuclear low-spin manganese(II) complexes derived from oxaloyldihydrazones, 1,10-phenanthroline and 2,2′-bipyridine
Syiemlieh, Ibanphylla,Kumar, Arvind,Kurbah, Sunshine D.,Lal, Ram A.
, p. 252 - 261 (2018)
Low-spin manganese (II) complexes [MnII(H2slox) (bipy)] (1), [MnII(H2slox) (phen)] (2), [MnII(H2slox) (phen)].1.5.H2O (2a), [MnII(H2nph) (bipy)].H2O (3) and [MnII(H2nph) (phen)].H2O (4) were synthesized from oxaloyldihydrazones in methanolic-water medium. The stoichiometry of the complexes was established by analytical, molecular weight and thermoanalytical data. Based on the data obtained from molar conductance, UV–visible, Infrared spectral, magnetic moment and electron paramagnetic resonance spectroscopic studies, the structures of the complexes have been established. From molar conductance it is suggested that all the complexes are non-electrolyte in DMF medium. The complex (2a) is monomeric in nature whereas the complexes (1) to (4) are dimeric based on the molecular weight data. The effective magnetic moment of complexes (1) to (4) show metal-metal interaction while complex (2a) has no metal-metal interaction. The complexes (1)–(4) show two quasi-reversible metal centred electron transfer reaction involving MnII/MnI/Mn0 redox reactions in DMF medium.
Synthesis and characterization of homotrimetallic copper complexes derived from bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone
Chanu,Kumar,Lemtur,Lal
, p. 854 - 861 (2012)
Copper (II) complexes [Cu3(nph)(μ2-X) 2(H2O)6]·2H2O [X = Cl (1), (ClO4) (3)] and [Cu3(nph)(NO3) 2(H2O)6] (2) have been synthesized from bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone in methanol medium and characterized. The structures of the complexes have been discussed in the light of data obtained from analytical, thermoanalytical, mass spectral studies, molar conductance, magnetic moment, electronic, EPR, IR, FT-IR spectroscopic studies. The molar conductance values for the complexes fall in the region 0.5-0.9 Sm2 mol-1 in DMSO solution indicating that all of them are non-electrolyte. The magnetic moment values for the complexes suggest weak M-M interaction in the structural unit of the complexes. The dihydrazone ligand is present in enol form in all of the complexes. Copper centre has tetragonally distorted octahedral stereochemistry in chlorido and perchlorato complexes while in nitrato complex, copper has mixed square-pyramidal and distorted-octahedral stereochemistry. The EPR parameters of the complexes indicate that the copper centre has the doublet state as the ground state.
Assessment of conformational, spectral, antimicrobial activity, chemical reactivity and NLO application of Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone)
Rawat, Poonam,Singh
, p. 344 - 355 (2015)
An orange colored pyrrole dihydrazone: Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone) (PDBO) has been synthesized by reaction of oxalic acid dihydrazide with 2,5 diformyl-1H-pyrrole and has been characterized by spectroscopic analysis (1H, 13C NMR, UV-visible, FT-IR and DART Mass). The properties of the compound has been evaluated using B3LYP functional and 6-31G(d,p)/6-311+G(d,p) basis set. The symmetric (3319, 3320 cm-1) and asymmetric (3389, 3382 cm-1) stretching wave number confirm free NH2 groups in PDBO. NBO analysis shows, inter/intra molecular interactions within the molecule. Topological parameters have been analyzed by QTAIM theory and provide the existence of intramolecular hydrogen bonding (N-H?O). The local reactivity descriptors analyses determine the reactive sites within molecule. The calculated first hyperpolarizability value (β0 = 23.83 × 10-30 esu) of pyrrole dihydrazone shows its suitability for non-linear optical (NLO) response. The preliminary bioassay suggested that the PDBO exhibits relatively good antibacterial and fungicidal activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Aspergillus niger. The local reactivity descriptors - Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) analyses have been used to determine the reactive sites within molecule.
Synergistic mechanism of ZnFe2O4/ZnO nanopowder in photocatalytic degradation of acid orange 7
Zulfiqar Ahmed,Chandrasekhar,Jahagirdar,Nagabhushana,Nagabhushana
, p. 607 - 612 (2018)
ZnFe2O4/ZnO nanopowder was prepared by solution combustion method. The characterization of the nanopowder was done by powder X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Powder X-ray diffraction pattern of the nanopowder exhibited the spinel phase of zinc ferrite and wurtzite phase of zinc oxide. The nanopowder was used for the photocatalytic removal of acid orange dye 7 from its aqueous solution. The effect of various factors such as initial dye concentration, dosage of the photocatalyst and irradiation time was studied. An analysis of the results indicated that the dye degradation was more in case of 10 and 20 ppm dye solutions. The dye degradation decreased with increasing initial concentration. ZnFe2O4/ZnO can be used as a better photocatalyst for the removal of dyes from their aqueous solutions.
Low-spin manganese(II) and high-spin manganese(III) complexes derived from disalicylaldehyde oxaloyldihydrazone: Synthesis, spectral characterization and electrochemical studies
Syiemlieh, Ibanphylla,Kumar, Arvind,Kurbah, Sunshine D.,De, Arjune K.,Lal, Ram A.
, p. 343 - 352 (2018)
Low-spin manganese(II) complexes [MnII(H2slox)].H2O (1), [MnII(H2slox)(SL)] (where SL (secondary ligand) = pyridine (py, 2), 2-picoline (2-pic, 3), 3-picoline (3-pic, 4), and 4-picoline (4-pic, 5) and high-spin manganese(III) complex Na(H2O)4[MnIII(slox)(H2O)2].2.5H2O have been synthesized from disalicyaldehyde oxaloyldihydrazone in methanolic – water medium. The composition of complexes has been established by elemental analyses and thermoanalytical data. The structures of the complexes have been discussed on the basis of data obtained from molar conductance, UV visible, 1H NMR, infrared spectra, magnetic moment and electron paramagnetic resonance spectroscopic studies. Conductivity measurements in DMF suggest that the complexes (1–5) are non-electrolyte while the complex (6) is 1:1 electrolyte. The electronic spectral studies and magnetic moment data suggest five – coordinate square pyramidal structure for the complexes (2–5) and square planar geometry for manganese(II) in complex (1). In complex (6), both sodium and manganese(III) have six coordinate octahedral geometry. IR spectral studies reveal that the dihydrazone coordinates to the manganese centre in keto form in complexes (1–5) and in enol form in complex (6). In all complexes, the ligand is present in anti-cis configuration. Magnetic moment and EPR studies indicate manganese in +2 oxidation state in complexes (1–5), with low-spin square planar complex (1) and square pyramidal stereochemistries complexes (2–5) while in +3 oxidation state in high-spin distorted octahedral stereochemistry in complex (6). The complex (1) involves significant metal – metal interaction in the solid state. All of the complexes show only one metal centred electron transfer reaction in DMF solution in cyclic voltammetric studies. The complexes (1–5) involve MnII→MnI redox reaction while the complex (6) involves MnIII→MnII redox reaction, respectively.
Synthesis, molecular structure, multiple interactions and chemical reactivity analysis of a novel ethyl 2-cyano-3-[5-(hydrazinooxalyl- hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate and its dimer: A combined experimental and theoretical (DFT and QTAIM) approach
Singh,Kumar, Amit,Tiwari,Rawat, Poonam
, p. 420 - 430 (2013)
A detailed spectroscopic analyses of a newly synthesized ethyl 2-cyano-3-[5-(hydrazinooxalyl-hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate (3) have been carried out using 1H and 13C NMR, UV-Visible, FT-IR and mass spectroscopic techniques. All the quantum chemical calculations have been carried out using DFT level of theory, B3LYP functional and 6-31G(d,p) as basis set. The 1H and 13C NMR chemical shifts are calculated using gauge including atomic orbitals (GIAOs) approach in DMSO-d 6. TD-DFT is used to calculate the energy (E), oscillatory strength (f) and wavelength absorption maxima (λmax) of various electronic transitions and their nature within molecule. Natural bond orbital (NBO) analysis is carried out to investigate the various intra and intermolecular interactions in dimer and their corresponding second order stabilization energy (E(2)). A combined theoretical and experimental vibrational analysis confirms the existence of dimer and the binding energy of dimer is calculated as 9.21 kcal/mol using DFT calculations. To determine the energy and nature of different interactions topological parameters at bond critical points (BCPs) have been analyzed by Bader's 'atoms in molecules' (AIMs) theory in detail. Electrophilic charge transfer (ECT) is calculated to investigate the relative electrophilic or nucleophilic behavior of reactant molecules involved in chemical reaction. Global electrophilicity index (ω = 5.5836 eV) shows that title molecule (3) is a strong electrophile. The local reactivity descriptors such as Fukui functions (fk+,fk-), local softness (sk+,sk-) and electrophilicity indices (ωk+,ωk-) analyses are performed to determine the reactive sites within molecule.
Synthesis, spectroscopic (electronic, IR, NMR and ESR) and theoretical studies of transition metal complexes with some unsymmetrical Schiff bases
Singh, Vinod P.,Singh, Shweta,Singh, Divya P.,Tiwari,Mishra, Monika
, p. 71 - 78 (2014)
Two unsymmetrical Schiff bases, glyoxal salicylaldehyde oxalic acid dihydrazone (gsodh) and glyoxal salicylaldehyde malonic acid dihydrazone (gsmdh) and their Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. The structures of metal complexes are elucidated on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, electronic, ESR, IR and NMR (1H and 13C) spectral studies. Both ligands show monobasic tetra-dentate behaviour, bonding through CO, two CN and a phenolate group. The electronic spectral studies in solid state indicate a square planar geometry for Ni(II) and Cu(II) complexes and a tetrahedral geometry for Co(II) complexes. However, Co(II) and Cu(II) complexes adopt octahedral geometry in DMSO solution. The ESR spectra of Cu(II) complexes in DMSO solution at 77 K predict an elongated tetragonal distorted octahedral geometry around metal ion and presence of unpaired electron in dx 2-y2 orbital. Further, the structures of ligands and their Ni(II) complexes have been satisfactorily modelled by calculations based on density functional theory (DFT). The electronic spectra of Ni(II) complexes are also analyzed in depth with the help of time dependent-DFT (TD-DFT). The theoretical analyses of electronic structure and molecular orbitals have demonstrated that the high-energy absorption bands are M → L charge transfer and low energy transitions are d-d transitions.
Synthesis, characterization, computational, conductometric titration and DNA binding studies of N′1,N′2?bis(3?hydroxy?5,5?dimethylcyclohex?2?en?1?ylidene)oxalohydrazide complexes
Abu El-Reash,Zaky,El-Gamil, Mohammed M.,El-Emam
, (2019)
A series of Co(II), Ni(II) and Cu(II) complexes were synthesized with N′1,N′2?bis(3?hydroxy?5,5?dimethylcyclohex?2?en?1?ylidene)oxalohydrazide (H4DOX). The geometry of isolated solid compounds was discussed by various spectroscopic methods. The optimized structures of complexes were confirmed by applying DFT theory. Also, the formation and association constants as well as Gibbs free energies of N′1,N′2?bis(3?hydroxy?5,5?dimethylcyclohex?2?en?1?ylidene)oxalohydrazide complexes were estimated at 298.15 K in a mixed solvent (DMSO?EtOH). Moreover, biological activity was tested for all isolated compounds.
Divalent cobalt, copper and zinc complexes of (2Z,2′Z)-2,2′-(oxalylbis(hydrazin-2-yl-1-ylidene))dipropionic acid (H4OPA): Synthesis, characterization, computational, conductometric titration and biological potency
Abou-Melha, Khlood S.
, (2021/10/02)
A new series of Co(II), Cu(II) and Zn(II) complexes have been synthesized with (2Z,2′Z)-2,2′-(oxalylbis(hydrazin-2-yl-1-ylidene))dipropionic acid (H4OPA). Specific spectroscopic methods used for the investigation of the prepared solid compounds' structure. The results of analytical and spectroscopic investigation revealed that ligand behaves as neutral tetradentate, binegative hexadentate and tetra-negative hexadentate with Cu(II), Co(II) and Zn(II) metal ions, respectively. The 1:1 binding manner between ligand, H4OPA and Cu2+ ions was evaluated by Job-plot technique. By applying the DFT theory, the optimized structures of the complexes were verified. In order to determine the kinetic and thermodynamic parameters by Horowitz–Metzger and Coats–Redfern approaches, thermal degradation curves for Co(II) complex was discussed. Furthermore, the association and formation constants as well as their ΔG values energies of Co(II) and Cu(II) complexes have been evaluated at 298.15 K in a 5% mixture of DMSO and ethanol. The conductometric results showed that the formation of Co(II) metal ion was (1:2) (L/M) but, the metal ion Cu(II) exhibits (1:3) (L/M) formation ratio. Moreover, all isolated compounds have been tested for biological potency shows that Zn(II) complex had the highest biological activity.
