This work describes FT-IR studies results on adsorption of Cu(II) metal cation. Adsorption has been performed on 3A, 4A, 5A, AW-300, ammonium Y zeolite, organophilic, and molecular sieve zeolites using aqueous solution of the metal studied. Changes in intensities and positions of the pseudolattice bands corresponding to ring vibrations have been observed in the measured spectra. These changes are expected particularly in the pseudolattice bands connected with the presence of alumino- and silicooxygen tetrahedral rings in the zeolite structure. Also, Cu(II) adsorbed zeolites were each tested for their ability to catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole. The Cu(II) adsorbed zeolites display efficiency in the disproportion reactions of hydrogen peroxide, producing water and dioxygen.
Hydrogen peroxide is an ubiquitous metabolite in living systems, produced at increased levels in a variety of pathological situations. Therefore suppressing or at least controlling H_2O_2 production is important. Catalase enzymes can convert hydrogen peroxide into water and dioxygen and a similar role can be played by transition metal ions or some radiopharmaceuticals. (1) TcO_4^-, (2) Tc-99m mercaptoacetyltriglycine (MAG3) and (3) Tc-99m methoxyisobutylisonitrile (MIBI) were each tested for their ability to catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole. It was found that (2) and (3) exhibit acceptable catalase-like activity compared to the Tc-99m pertechnetate.
Catechol oxidase catalyses the oxidation of a broad range of catechols to the corresponding o-quinones through the four-electron reduction of molecular oxygen to water, without acting on tyrosine. The resulting highly reactive quinones autopolymerize to form brown polyphenolic catechol melanins, a process thought to protect the damaged plant against pathogens or insects. This work describes the catalytic activity of some radiopharmaceuticals like Tc-99m pertechnetate, Tc-99m mercaptoacetyltriglycine (MAG3), Tc-99m nanocolloid, Tc-99m methylenebis(phosphonic acid) (MDP) and Tc-99m methoxyisobutylisonitrile (MIBI) for oxidation of catechol. The catalytic oxidation of 3,5-di-tert-butylcatechol by selected radiopharmaceuticals saturated with molecular oxygen was studied in a homogeneous system. All the radiopharmaceuticals exhibited catecholase-like activity.
We have reported herein the synthesis of a novel quinone derivative ligand containing the Schiff base and its Cu(II) complex starting from 1,4-naphthoquinone. Synthesized compounds were characterized using the Fourier transform infrared, UV-Vis, elemental analysis, inductively coupled plasma optical emission spectrometry, molar conductivity, and magnetic susceptibility measurements. The free ligand was also characterized by ¹H- and ¹³C-NMR spectra. Elemental analyses, stoichiometric and spectroscopic data indicated that the metal:ligand ratio is 1:2 and octahedral structure is proposed for the metal complex of the Schiff base ligand. Computational quantum calculations were also performed using DFT/B3LYP level of theory with 6-311++G(d,p) basis set for the synthesized ligand. It was found that the experimental and theoretical spectroscopic data were consistent.
Two novel Schiff base ligands, 2,2'-((pentane-2,4-diylidene)bis(azanylylidene))bis(4-chlorophenol) and 2,2'-((pentane-2,4-diylidene)bis(azanylylidene))bis(4-methylphenol) were prepared by condensation reaction of acetylacetone with 2-amino-4-chlorophenol and 2-amino-4-methylphenol, respectively. Mononuclear Cu(II) complex of each ligand was also synthesized. These compounds were characterized by elemental analyses, inductively coupled plasma optical emission spectrometry, the Fourier transform infrared spectra, UV-Vis, molar conductivity, and magnetic susceptibility measurements. The ligands have been further characterized by ¹H- and ¹³C-NMR. The results suggest that the metal complexes of the ligands have a metal:ligand ratio of 1:1 and the Cu(II) ions are coordinated by the phenolic oxygen atoms and imine nitrogen atoms of the ligands. Moreover, the quantum chemical calculations of the compounds have been performed using the density functional theory. It has been found that the calculated spectroscopic values are in a good agreement with experimental data.
The bidentate Schiff base ligand 4-chloro-2-[1-(4-phenylphenyl)ethylideneamino]phenol and its mononuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. Ligand and metal complexes were characterized by elemental analyses, magnetic susceptibility, molar conductivity, ¹H- and ¹³C-NMR, the Fourier transform infrared, UV-Vis, inductively coupled plasma optical emission spectrometry, and thermogravimetric-differential thermogravimetric studies. The results suggest that the mononuclear complexes have a metal to ligand mole ratio of 1:2 and the metal(II) ions are coordinated with the phenolic oxygen and imine nitrogen atoms. Octahedral structures are proposed for the complexes of the Schiff base ligand. Furthermore, the complexes were checked for their efficiency to decolorize the dye methylene blue. In our experiments we found that metal(II) complexes had an acceptable decolorization efficiency against the dye methylene blue.
The purpose of this study is synthesis, characterization and enzyme activity functions of novel dinuclear metal complexes. Therefore two new dinuclear heterometallic cobat(II)-copper(II) complexes have been synthesized and structurally characterized by using Fourier transform infrared method, elemental analysis, inductively coupled plasma optical emission spectrometry, molar conductivity, magnetic moment measurements and thermal analysis. Spectroscopic and stoichiometric data of the metal complexes indicated that the metal:ligand ratio of the complexes were found to be 2:1. Both of the complexes are 1:2 electrolytes as shown by their molar conductivities and paramagnetism. The subnormal magnetic moment values of the dinuclear complexes were explained by an antiferromagnetic interaction. Additionally complexes were each tested both for their ability to oxidation reaction of 3,5-di-tert-butylcatechol to the 3,5-di-tert-butyl-o-benzoquinone presence of O₂ and catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole. It was found that both of the complexes exhibited good catecholase and catalase-like enzyme activity.
A novel ligand, N,N"-(4-methyl-1,2-phenylene)bis(2-(biphenyl-4-yl)-N'-hydroxy-2-oxoacetimidamide) (H₂L) with its Cu(II) and Mn(II) complexes were synthesized in this study. All compounds synthesized were also characterized by ¹H- and ¹³C-NMR, the Fourier transform infrared, elemental analysis, inductively coupled plasma optical emission spectrometry, molar conductivity, magnetic susceptibility measurements and thermogravimetric analysis. Vascular endothelial growth factor-2 (VEGFR-2) and cyclooxygenase-2 (COX-2) inhibition is often used as a parameter for being a potent anticancer agent in docking studies. For this purpose, synthesized and characterized ligand was investigated by molecular docking study to test its inhibitory effect against angiogenic factors VEGFR-2 and COX-2.
A novel aminoketooxime ligand and its mononuclear Cu(II) and Mn(II) complexes were synthesized. The structures of the synthesized compounds were illuminated by elemental analysis, inductively coupled plasma optical emission spectrometry, the Fourier transform infrared, ¹H- and ¹³C-NMR, UV-Vis, magnetic susceptibility and conductivity measurements. According to the characterization studies ligand to metal ratio was found to be 2:1 with strong binding affinity of the ligand to the metal ions. In addition, complexes have been tested for their catecholase and phenoxazinone synthase-like activities. Kinetic studies were also carried out yielding V_{max}, k_{cat} and K_{M} values of both complexes for catecholase and phenoxazinone synthase-like activities. Both complexes efficiently catalyzed the reactions of the enzymes they mimicked.
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