Synthesis, stereochemistry and antimicrobial activity of copper(II) and nickel(II) complexes of 4-phenylsemicarbazones

2-Acetylpyridine-(4-phenylsemicarbazone) and o-vanillin-(4-phenylsemicarbazone) have been prepared and characterized on the basis of elemental analyses, infrared, electronic, 1H and 13C NMR spectra. Several nickel(II) and copper(II) complexes have been obtained from these ligands. The IR spectra of the ligands as well as those of their complexes suggest that 2-acetylpyridine-(4-phenylsemicarbazone) is a neutral tridentate molecule while o-vanillin-(4-phenylsemicarbazone) is a monobasic tridentate molecule. On the basis of the analytical data, magnetic moments and spectral data, a square-planar geometry has been proposed for the nickel(II) and copper(II) complexes with these ligands. Some representative complexes of copper(II) and nickel(II) were found to have remarkable antifungal and antibacterial activity.KEY WORDS: 4-Phenylsemicarbazone, Metal complexes, Stereochemistry, Antimicrobial activity Bull. Chem. Soc. Ethiop. 2011, 25(3), 361-370

Synthesis, crystal structure and magnetic properties of [Cu(mal)(abpt)(H2O)].3/2H2O and [Cu2(sq)(abpt) 2].2H2O (mal = malonate, sq = squarate, abpt =4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole)

Two new mixed-ligand complexes of formula [Cu(mal)(abpt)(H2O)].3/2H2O (1) and [Cu2(sq)(abpt) 2].2H2O (2) [mal = malonate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole and sq = squarate], have been prepared and characterized by X-ray crystal structure determination and magnetic studies. Complex 1 crystallizes in the monoclinic system, space group C2/c, with a = 14.0086(2) Å, b = 10.0980(2) Å, c = 25.630(4) Å; β = 97.5900(10) o, and Z = 8. Complex 2 crystallizes in the triclinic system, space group P-1 with a = 7.5696(15) Å, b = 8.4697(17) Å, c = 11.049(2) Å; β = 93.00(3)o,  α = 96.98(3), γ = 90.111(3) and Z = 1. Complex 1 consist of a neutral mononuclear [Cu(mal)(abpt)(H2O)] unit and water molecule of crystallization in a distorted square pyramidal coordination sphere, while complex 2 is viewed as being made up of [Cu(sq)(abpt)2] units with the squarato ligand bridging the two copper(II) cations. Variable temperature magnetic behaviour of the complexes reveals the existence of weak antiferromagnetic interaction for complex 1 and weak ferromagnetic intrachain interaction for complex 2.KEY WORDS: Copper(II) complexes, Mixed-ligand, Magnetic properties, Malonate, Squarate, 4-Amino-3,5-di-2-pyridyl-4H-1,2,4 triazoleBull. Chem. Soc. Ethiop. 2011, 25(1), 53-60

<b>Synthesis, crystal structure and magnetic properties of [Cu(mal)(abpt)(H₂O)].3/2H₂O and [Cu₂(sq)(abpt) ₂].2H₂O (mal = malonate, sq = squarate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole) </b>

Two new mixed-ligand complexes of formula [Cu(mal)(abpt)(H2O)].3/2H2O (<b>1</b>) and [Cu2(sq)(abpt)2].2H2O (<b>2</b>) [mal = malonate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole and sq = squarate], have been prepared and characterized by X-ray crystal structure determination and magnetic studies. Complex <b>1</b> crystallizes in the monoclinic system, space group C2/c, with a = 14.0086(2) Å, b = 10.0980(2) Å, c = 25.630(4) Å; β = 97.5900(10) o, and Z = 8. Complex <b>2</b> crystallizes in the triclinic system, space group P-1 with a = 7.5696(15) Å, b = 8.4697(17) Å, c = 11.049(2) Å; β = 93.00(3)o, α = 96.98(3), γ = 90.111(3) and Z = 1. Complex <b>1</b> consist of a neutral mononuclear [Cu(mal)(abpt)(H₂O)] unit and water molecule of crystallization in a distorted square pyramidal coordination sphere, while complex <b>2</b> is viewed as being made up of [Cu(sq)(abpt)₂] units with the squarato ligand bridging the two copper(II) cations. Variable temperature magnetic behaviour of the complexes reveals the existence of weak antiferromagnetic interaction for complex <b>1</b> and weak ferromagnetic intrachain interaction for complex <b>2</b>

Adsorption and gas-sensing investigation of oil dissolved gases onto nitrogen and sulfur doped graphene quantum dots

Burning hydrocarbons as fuel, which produces carbon dioxide and water, is a major contributor to anthropogenic global warming. Hydrocarbons are introduced into the environment through their extensive use as fuels and chemicals as well as through leaks or accidental spills during exploration, production, refining, or transport of fossil fuels. Herein, theoretical calculations based on density functional theory (DFT) was applied to investigate the adsorption behavior of C2H4, CH4 and H2 on graphene quantum dot surfaces doped with Nitrogen (N) and sulfur (S) (GQD_N, GQD_S). Theoretical calculations in this study were obtained with the dispersion correction in consideration so as to predict intermolecular interactions alongside B3LYP-D3(BJ)/6-311+G (d, p). The sites that were doped with N and S atom were found to be more stable and suitable for gas adsorption. The adsorption energy was computed to establish the surface abilities of the adsorptions under investigation. Gas adsorptions on surfaces showed similar high negative values. We may deduce from the computed adsorption energies that GQD_N and GQD_S have strong adsorptions and considered adsorptions are thermodynamically favored. The ellipticity parameter calculated using the quantum theory of atoms in molecules (QTAIM), as well as the stabilization energies obtained from natural bond orbitals (NBO), confirmed the stability of surfaces upon gas adsorptions. QTAIM also confirmed remarkable intermolecular interactions. This result also agrees with that for non-covalent interactions, which predicted weak intermolecular interactions between surface and gas molecules. GQD_N and GQD_S are good adsorbents that can adsorb C2H4, CH4, and H2 gases, respectively

Ab-initio study of structural, electronic, phonon, X-ray spectroscopy, and the optoelectronic properties of D-block metals (Cr, Mn, Co, and Ni) substitution of barium oxide based-perovskites

Recently, transition metal doped superlattice has shown an anomalous optical band gap of 1.6 eV, about 1 eV lower than either parent element (Barium) majorly, making it appropriate for several applications including magnetism and superconducting materials. In the current study, the structural, electronic, phonon, thermodynamic, and the magnetic ordering of BaXO3 (X = Cr, Mn, Co, and Ni) has been examined using density functional theory (DFT). From the results, the investigated materials show a ferromagnetic behavior with the band gap of range 0.95–1.04 eV, and average absolute magnetization are 2.64, 3.67, 3.19, and 0.01 Bohr magneton/cell for BaCrO3, BaMnO3, BaCoO3, and BaNiO3, respectively. Furthermore, it is conceivable that the Compton profiles of BaXO3(X= Cr, Mn, Co, and Ni) are magnetic due to the substantial exchange-correlation dependence of their Compton profiles, which is shown from the phonon and X-ray distributions, thermodynamic calculation, and mechanically portrayed features of BaXO3. It was further discovered that doping could increase each TM (Cr, Mn, Co, and Ni) atom's magnetic moment. This study demonstrates a novel method for utilizing this revolutionary kind of cubic ferrites for spintronic applications in solid-state electronics

Investigating the intermolecular interactions in the explicitly solvated complexes of lomustine with water and ethanol

Lomustine is an alkylating chemotherapy drug that is used to treat diverse types of cancer, including brain tumors, Hodgkin's lymphoma, and non-Hodgkin's lymphoma, which works by interfering with the DNA in cancer cells, preventing them from dividing and growing. As such the lipid bilayer of the cell and body fluids provides the environments in which lomustine (lmt) performs its biological function. Chemical reactions involving biological systems occur in the liquid phase, where accurate modeling of the reaction pathways considers the influence of the solvent used. Implicit solvation adequately accounts for these effects but falls short when evaluating solvent-solute interactions. This study aims to explore the structures, thermodynamics, reactivity, UV–vis spectroscopy, energy decomposition analysis, and the interaction energies of lmt with molecules of water and ethanol (n = 1, 2, and 3), using density functional theory (DFT) at the ωB97XD/6–311++G (d, p) level of theory. The thermodynamics results reveal that the polarity of water molecules significantly influences the interaction strength of the studied systems as the interaction observed between lmt with W1, Et1, and Et2 is feasible and spontaneous, compared to others. The stability of the different clusters depends on the intermolecular hydrogen bonds formed between the drug and the polar solvent as explicated by the H-bond interaction distance. Also, the interaction of lmt with each of the solvents causes a slight deformation in the geometry of the lmt, moreover, the reactivity descriptors predicted the interaction of lmt to increase with a corresponding increase in the addition of water molecules

Molecular Modeling of Cu‑, Ag‑, and Au-Decorated Aluminum Nitride Nanotubes for Hydrogen Storage Application

The stabilities, electronic properties, and reactivities of hydrogen interactions with Cu-, Ag-, and Au-decorated aluminum nanotubes (AlNNT), H2-AlNNT, H2-Ag@AlNNT, H2-Au@AlNN T, and H2-Cu@AlNNT, for efficient hydrogen storage were investigated using density functional theory (DFT) computations at the ωB97XD/def2svp level of theory. The electron shared by H2-Ag@AlNNT, H2-Au@AlNNT, and H2-Cu@AlNNT, as well as the chemical bond created with the adsorbed hydrogen molecule, indicate chemisorption from the electron localization function (ELF) analysis, which is compatible with the adsorption energies obtained. H2-Cu@AlNNT exhibited molecular physisorption with an average hydrogen adsorption energy (Eads) of −0.027 eV, whereas H2-AlNNT, H2-Ag@AlNNT, and H2-Au@AlNNT exhibited chemisorption behavior. The molecular adsorption energies for H2-Ag@AlNNT and H2-Au@AlNNT were, respectively, −0.136 and −0.081 eV. Thus, in comparison to the other H2-adsorbed systems under investigation, the highest obtained adsorption energies were observed for these two decorated nanotube systems, respectively. H2-Ag@AlNNT and H2-Au@AlNNT are, therefore, better when compared to the other studied materials in terms of storage and adsorption of hydrogen molecules. Additionally, the negative value of Eads shows that the stated hydrogen molecule’s adsorption is thermodynamically efficient. Also, in comparison with the Department of Energy (DOE) standard, the calculated wt % values for the studied systems were found to be 6.0 and 5.8 wt % for the AlNNT and metal-decorated systems, respectively. This is quite lower than the recommended standard; however, adsorption of more hydrogen molecules and surface engineering could improve the obtained wt %. The desorption temperature was also found to be within the required range for storage materials, according to DOE. Ab initio molecular dynamics simulation also confirms surface stability. Correspondingly, the NCI analysis reveals that the nature of the connection is linked to van der Waals forces and that the hydrogen molecule interacts well with the adsorbent surfaces. These phenomenal results enshrined probably the noble metal-decorated AlN nanotube materials as efficient reservoir materials for hydrogen storage

Modeling of Anthranilhydrazide (HL1) Salicylhydrazone and Its Copper Complexes Cu(I) and Cu(II) as a Potential Antimicrobial and Antituberculosis Therapeutic Candidate

Antimicrobial and antituberculosis activities of transition metal complex Cu(I) and Cu(II) from salicylhydrazone of anthranihydrazide (HL1) have been theoretically investigated using DFT methods at ωB97XD, PBEPBE, MPW1PW91, HSEH1PBE, CAM-B3LYP/6-311++G(d,p) level of theory. Owing to the fact that microbial and tuberculosis attacked still prevail despite studies reported in the literatures. This study utilized a higher theoretical model to unravel necessary information about the possible application of the HL1 and its complexes as a potential drug candidate. The results obtained reveal that the ligand (HL1) had the higher energy gap for the HES and MPW whereas, it Cu(II) complex had the least energy gap making it more reactive in the biological environment compared to its counterpart. The Natural Bond orbital (NBO) analysis reveals molecular interactions are of four kinds; LP→BD*, LP→LP*, LP*→BD*, BD*→BD*, and BD*→LP* where the higher perturbation energy was observed from BD*(C2-C3) → BD*(C4- 5) with the energy of 231.74 kcal/mol. The vibration analysis shows that the studied complexes have 32 atoms and 90 normal modes, with 20 symmetric, 7 asymmetric, 31 bending, and 32 ring torsional distribution. And their theoretical wavelength of absorption was observed to be in good agreement with experimental reported values. Cu(II) was observed with the highest dipole moment and first-order hyperpolarizability (βtotal) with corresponding values of 9.30D and 19.268 which shows its can be good for medicinal application. Molecular docking screening showed that the ligand and its complexes have better antimicrobial activities compared to antituberculosis.</p