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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full... more
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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Copper(II) complexes of pyridine-based ligands functionalized with alanine (PydiAla) and tyrosine (PydiTyr) moieties have been synthesized as novel superoxide dismutase mimics. The complexes were characterized by pH-potentiometric,... more
Copper(II) complexes of pyridine-based ligands functionalized with alanine (PydiAla) and tyrosine (PydiTyr) moieties have been synthesized as novel superoxide dismutase mimics. The complexes were characterized by pH-potentiometric, spectroscopic (UV-vis, circular dichroism, mass spectrometry, electron paramagnetic resonance spectroscopy), computational (DFT), and X-ray diffraction methods. Both ligands form high stability copper(II) complexes via the (Npy,N-,N-) donor set supported by the binding of the carboxylate pendant arms. Although the coordination mode is the same for the two systems, the tyrosine containing counterpart exhibits increased copper(II) binding affinity, which is most likely due to the presence of the aromatic moiety of the side chains. Both copper(II) complexes are capable of binding N-methylimidazole, and the formation of the corresponding ternary species was observed at physiological pH. The binary and ternary copper(II) complexes exhibit high SOD activity. The PydiTyr complex exhibits about 1 order of magnitude higher activity than the PydiAla complex. This is probably due to the presence of the phenolic OH group in the former species, which promotes the binding of the superoxide anion radical to the metal center. The results serve as a basis for designing highly efficient copper(II) mimics for medical and practical applications.
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Research Interests: Chemistry, Kinetics, Decomposition, Electron Transfer, Iron, and 4 moreSulfur, Ion, Metal ion, and Redox
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Stability constants of the complexes formed in the reaction of [Pd(bpma)](2+) [bpma=bis(pyridin-2-ylmethyl)amine] with monodentate nitrogen and thioether ligands including uridine, MeUH, cytidine, MeC, EtGH, AcHis, AcHm, AcLys and AcMet... more
Stability constants of the complexes formed in the reaction of [Pd(bpma)](2+) [bpma=bis(pyridin-2-ylmethyl)amine] with monodentate nitrogen and thioether ligands including uridine, MeUH, cytidine, MeC, EtGH, AcHis, AcHm, AcLys and AcMet were determined by potentiometric method. The coordination chemistry of [Pd(bpma)](2+) shows a significant similarity to that of [Pd(terpy)](2+), but it is different from [Pd(dien)](2+). The formation of hydroxo and dinuclear complexes is especially enhanced in the case of [Pd(bpma)](2+) and [Pd(terpy)](2+), but the affinity of palladium(II) ions for the coordination of thioether residues is reduced in the presence of pyridine nitrogen atoms. Stopped-flow kinetic measurements reveal that the substitution reactions of the thioether ligand AcMet are much faster than those of the N-donor cytidine. The presence of the two pyridyl residues significantly enhances the kinetic reactivity of [Pd(bpma)](2+) as compared to that of [Pd(dien)](2+). The Pd-S(thioether) bonded species can be important intermediates in multicomponent systems, but the equilibrium state is characterised by the formation of Pd-N bonded species. The complex [Pd(bpma)NO(3)]NO(3) has been prepared in solid state and its structure was elucidated by single crystal X-ray diffraction method.
Research Interests: Thermodynamics, Chemistry, Inorganic Chemistry, Kinetics, Magnetic Resonance Spectroscopy, and 15 moreMedicine, Potentiometry, Sulfides, Nitrogen, Palladium, Methionine, Metal ion, Calorimetry, Inorganic Biochemistry, Thermodynamic Stability, Potentiometric Titration, Ligands, Thermodynamic Parameter, Steric Effects, and Rate Constant
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full... more
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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ABSTRACT
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... Chem. 1968, 7, 235. Khan, AH; Higginson, WCE J. Chem. Soc., Dalton Trans. ... (d) Glebov, V. A. Electronic Structure and Properties of Uranyl Compounds (in Russian); Energoatomizdat: Moscow, 1983. (2) Hay, PJ; Wadt, WR; Kahn, LR;... more
... Chem. 1968, 7, 235. Khan, AH; Higginson, WCE J. Chem. Soc., Dalton Trans. ... (d) Glebov, V. A. Electronic Structure and Properties of Uranyl Compounds (in Russian); Energoatomizdat: Moscow, 1983. (2) Hay, PJ; Wadt, WR; Kahn, LR; Raffenetti, RC; Phillips, D. HJ Chem. Phys. ...
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The stability constants for the complexes formed in the title systems are determined.
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Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) are systemic autoimmune diseases with complex symptoms and pathogenesis that are still not completely understood. Several studies showed that the trace element homeostasis... more
Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) are systemic autoimmune diseases with complex symptoms and pathogenesis that are still not completely understood. Several studies showed that the trace element homeostasis and also the levels of antioxidant plasma proteins are changed in autoimmune disorders; however, these results are controversial. In this study, the potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and iron (Fe) concentrations of the serum and proteins-immunoglobulin G (IgG), transferrin (Trf), albumin (Alb), and ceruloplasmin (Cp)-separated from serum samples by affinity chromatography were determined in patients with SLE and SS. Ca and K levels were found to be decreased in the case of both disorders compared to the control group, and the competitive antagonism of Cu and Zn was also observed: elevated Cu concentration together with a lower Zn concentration was measured in the sera of patients with autoimmune diseases. After fr...
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Elemental concentrations of deposited dust and leaf tissue are often used to assess the level of contamination, and for monitoring air pollution. Leaves of Platanus x acerifolia, Fraxinus excelsior and Acer campestre were used to assess... more
Elemental concentrations of deposited dust and leaf tissue are often used to assess the level of contamination, and for monitoring air pollution. Leaves of Platanus x acerifolia, Fraxinus excelsior and Acer campestre were used to assess the amount of deposited dust and the elemental concentrations of deposited dust and leaf tissue in and around the city of Miskolc, Hungary. Samples were collected from the nearby cement and steel factories and from urban, suburban and rural areas along an urbanization gradient. Both the cement and steel factories were in the suburban area of Miskolc, an influence the air quality of the city. The concentrations of Al, Ba, Cd, Cr, Fe, Na, Pb, Si, Sr and Zn were determined in the deposited dust and leaf tissue, using MP-AES. We found significant differences in the amounts of deposited dust between suburban and rural areas. There were no significant differences among the other areas compared to each other. Canonical discriminant analysis showed a good separation of areas and species based on the elemental concentrations of deposited dust and leaves. In the deposited dust, significant differences were found among studied areas in the case of Al, Ba, Cd, Cr, Fe, Na, Pb, Si, Sr and Zn. There were no significant differences among species in the elemental concentrations of deposited dust, with the exception of Na. However, the Al, Ba, Cr, Cu, Fe, Mn, Si, Sr and Zn concentrations in leaf tissue differed significantly among the studied areas. We found significant differences among leaves of various species in the case of Ba and Si. The organic matter content of leaf tissue was positively correlated with Zn concentration. In the cases of other elements there was no significant correlation between the organic matter content and the elements’ concentration in leaf tissue. Our results suggested that industrial activities and urbanization caused remarkable air contamination. Our findings suggest that the dust deposits on leaf surface may be useful indicators of atmospheric element air pollution. The reconstruction of abandoned industrial buildings are needed because, in addition to general urbanization, they have been a potential air pollution source, and still remain so.
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The stability constants for the complexes formed in the title systems are determined.
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The kinetics of the bromate ion‐iodide ion‐L‐ascorbic acid clock reaction was investigated as a function of temperature and pressure using stopped‐flow techniques. Kinetic results were obtained for the uncatalyzed as well as for the... more
The kinetics of the bromate ion‐iodide ion‐L‐ascorbic acid clock reaction was investigated as a function of temperature and pressure using stopped‐flow techniques. Kinetic results were obtained for the uncatalyzed as well as for the Mo(VI) and V(V) catalyzed reactions. While molybdenum catalyzes the BrO‐I− reaction, vanadium catalyzes the direct oxidation of ascorbic acid by bromate ion. The corresponding rate laws and kinetic parameters are as follows. Uncatalyzed reaction: r2 = k2[BrO] [I−][H+]2, k2 = 38.6 ± 2.0 dm9 mol−3 s−1, ΔH‡ = 41.3 ± 4.2 kJmol−1, ΔS‡ = −75.9 ± 11.4 Jmol−1 K−1, ΔV‡ = −14.2 ± 2.9 cm3 mol−1. Molybdenum‐catalyzed reaction: r′2 = k2[BrO] [I−] [H+]2 + kMo[BrO] [I−] [ H+]2[M0(VI)], kMo = (2.9 ± 0.3)106 dm12 mol−4 s−1, ΔH‡ = 27.2 ± 2.5 kJmol−1, ΔS‡ = −30.1 ± 4.5 Jmol−1K−1, ΔV‡ = 14.2 ± 2.1 cm3 mol−1. Vanadium‐catalyzed reaction: r′1 = kV[BrO] [V(V)], kV = 9.1 ± 0.6 dm3 mol−1 s−1, ΔH‡ = 61.4 ± 5.4 kJmol−1, ΔS‡ = −20.7 ± 3.1 Jmol−1K−1, ΔV‡ = 5.2 ± 1.5 cm3 mol−1. On th...
Research Interests: Chemistry, Catalysis, Kinetics, Chemical Kinetics, Vanadium, and 3 moreAscorbic Acid, Bromate, and Iodide
... Each reagent was added with individual automatic titrators accurate to better than 0.01 cm3 to provide a maximum dilution error of 0.13% in the ... The electrodes were calibrated such that the pH meter reading gave the hydrogen ion... more
... Each reagent was added with individual automatic titrators accurate to better than 0.01 cm3 to provide a maximum dilution error of 0.13% in the ... The electrodes were calibrated such that the pH meter reading gave the hydrogen ion concentration (-log [H+]), after the addition of a ...
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... (4) Diebler, H.; Rosen, P. Ber. Bunsen-Ges. Phys. Chem. 1972, 76, 103 1. (5) Moss, DB; Lin, C.; Rorabacher, DB J. Am. Chem. SOC. 1973, 95, 5179. (6) Sharma, V. S.; Leussing, DL Inorg. Chem. 1972, IJ, 138. (7) Pastemack, RF; Huber, PR;... more
... (4) Diebler, H.; Rosen, P. Ber. Bunsen-Ges. Phys. Chem. 1972, 76, 103 1. (5) Moss, DB; Lin, C.; Rorabacher, DB J. Am. Chem. SOC. 1973, 95, 5179. (6) Sharma, V. S.; Leussing, DL Inorg. Chem. 1972, IJ, 138. (7) Pastemack, RF; Huber, PR; Huber, UM; Sigel, H. Inorg. Chem. ...
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ABSTRACT
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... Chem. 1968, 7, 235. Khan, AH; Higginson, WCE J. Chem. Soc., Dalton Trans. ... (d) Glebov, V. A. Electronic Structure and Properties of Uranyl Compounds (in Russian); Energoatomizdat: Moscow, 1983. (2) Hay, PJ; Wadt, WR; Kahn, LR;... more
... Chem. 1968, 7, 235. Khan, AH; Higginson, WCE J. Chem. Soc., Dalton Trans. ... (d) Glebov, V. A. Electronic Structure and Properties of Uranyl Compounds (in Russian); Energoatomizdat: Moscow, 1983. (2) Hay, PJ; Wadt, WR; Kahn, LR; Raffenetti, RC; Phillips, D. HJ Chem. Phys. ...