Chemistry Journal of Moldova

DOI: dx.doi.org/10.19261/cjm.2007.02(1).11

Graphical Abstract: The inhibition of nornicotine nitrosation was studied. The concentration of nornicotine was 100 μM and nitrite 1000 μM. As inhibitors were used following compounds: ascorbic acid (as reference) (800, 1000, and 5000 μM), dihydroxyfumaric acid (1000 μM), (+)catechin (1000 μM), resveratrol (1000 μM), tartaric acid (1000 μM), quercetin (1000 μM), and grape seed extract (50, 100, 150 μg/ml). The best inhibitory effect was obtained for AAs at 5000 μM (90.7%), (+)Ct (95.5 %) and GSE at 150 μg/ml (96.1%). The small inhibitory effect was observed for TA – 22,5%.


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DOI: dx.doi.org/10.19261/cjm.2007.02(1).12

Graphical Abstract: The paper includes the study of the inhibition of the process of methemoglobinization at oxidation with nitrites in the presence of sodium dihydroxyfumarate (DFH3Na) and resveratrol (3,4’,5-trihydroxystilben). The experimental study was carried out by treatment of the erythrocyte mass by hemolysis and exposure to nitrite. The kinetic investigations were carried out in following conditions: [Resv] = (5.10-5 – 1.10-3) mol/l, [DFH3Na] = 1.10-6 – 5.10-6 mol/l; [HbO2]=1.10-3 mol/l; pH 7,1; t = 370C. The rate of transformation of HbO2 in the presence of resveratrol and DFH3Na was calculated from kinetic curves of consumption of the substrate and formation of MetHb obtained pectrophotometrically (λmax= 540 nm for HbO2 and λmax=630 for MetHb). It has been found out that the introduction of resveratrol and DFH3Na in the system HbO2 – NO2- causes the decrease of the autooxidation factor φ DFH3Na approximately by 1.1 – 2.5 times and φresveratrol by 1.1 – 1.7 times. The time of achievement of the maximum rate of oxidation of HbO2 dζ/dτ (where ζ is the rate of transformation of HbO2 in MetHb) increases while the phase of fast oxidation of HbO2 decreases with increase of content of inhibitors. The process of interaction of nitrites with reducers (such as DFH4, DFH3Na, resveratrol and (+)-catechine) was carried out as well. It has been established that degree of diminishing of the concentration of nitrites in the system RedH2-NO2- decreases as follows: DFH4.


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DOI: dx.doi.org/10.19261/cjm.2007.02(1).13

Graphical Abstract: Studies of the mineralogical composition of diatomite from the Ghidirim location of RM, as well as of the extracted clay phase are presented. The mineral phase of the diatomite contains a number of clay minerals, like montmorillonite (in a mixture with insignificant quantities of slightly chloritized montmorillonite), illite and kaolinite. Diatomite contains also non-clay components as fine-dispersed quartz and amorphous material, the more probable sources of which are opal, amorphous alumosilicates, aluminum and iron hydroxides. The applied procedure for separation of clay fractions by sizing settling in liquid media proves to be very useful, enabling possibilities for more accurate identification of the clay constituents of diatomic material. Procedure allows to separate very clean clay fraction especially rich in montmorillonite, which can be utilized itself as mineral adsorbent for practical purposes.


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DOI: dx.doi.org/10.19261/cjm.2007.02(1).14

Graphical Abstract: The paper considers a possibility of using the catalytic action of the carbonaceous adsorbents modified by different ways for the purification of various solutions, natural and wastewaters. It has been found that the oxidative destruction of organic (phenols, dyes, pesticides, etc.) and inorganic (H2S) contaminants in water solutions is considerably intensified in the presence of both ordinary activated carbons and especially, carbons with specially introduced catalytic additives. It is shown that the sewage treatment level is strongly affected by the amount and nature of a modifying agent introduced on the carbon surface.


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DOI: dx.doi.org/10.19261/cjm.2007.02(1).15

Graphical Abstract: The obtained results concerning the Ga (III) ion retention on flexible open cell polyurethane foam of polyether type pretreated with tri-n-butyl phosphate are presented. The influence of solution acidity, phases contact time, Ga (III) concentration and solution temperature have been investigated. The parameters of Ga (III) batch sorption have been optimized. On the basis of Langmuir isotherms, the sorption constants and the thermodynamic parameters, ∆G, ∆Η and ∆S have been calculated.

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DOI: dx.doi.org/10.19261/cjm.2006.01(1).01

Graphical Abstract: The results of investigation of oenotannins content in the seeds of different grape varieties are presented in the paper. It was demonstrated that the oenotannins content depends on the grape variety as well as on the geographycal zone of grape cultivation. A new procedure for

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DOI: dx.doi.org/10.19261/cjm.2006.01(1).02

Graphical Abstract: Three steroidal glycosides of spirostane series have been isolated from the seeds of Hyoscyamus niger L.(Solanaceae). Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods including one-dimensional, two-dimensional NMR and MS analysis. In the genus Hyoscyamus the given compounds have been found out for the first time.


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DOI: dx.doi.org/10.19261/cjm.2006.01(1).03

Graphical Abstract: The magnetic susceptibility (χT) of an unusual dissymmetric binuclear manganese corboxylate complex has been measured from 2 to 300K. The magnetic data which have been fitted with help of the Heisenberg Dirac Van Vleck HDVV spin-exchange Hamiltonian H = − J S 1 S 2 , indicate that an antiferromagnetic interaction equal to J = -0.90(1) cm-1 is present. A correlation between J values and Mn-H2O-Mn angles has been tempted.


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DOI: dx.doi.org/10.19261/cjm.2006.01(1).04

Graphical Abstract: Reaction in methanol solution of the trinuclear ‘basic’ chromium(III) acetate with Pr(NO₃)₃⋅5H₂O and further extraction by chloroform-acetone mixture led to the formation of novel unusual [Cr₃O(CH₃COO)₆(H₂O)₃]NO₃⋅HNO₃⋅H₂O (1) cluster with one “free” molecule of nitric acid. Complex 1 crystallizes in the monoclinic space group P21/c with, at room temperature, a = 13.624(2), b = 15.032(2), c = 15.180(2) Å, β = 112.98(3) °, Z = 4, and V = 2862.09 Å3. The obtained crystalline compound has been synthesized and characterized by IR and UV/Vis methods.


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DOI: dx.doi.org/10.19261/cjm.2006.01(1).05

Graphical Abstract: Heterometallic complexes of chromium (III) with some 3d metals have been synthesized based on nitrilotriacetic acid (H₃nta), like M(bpy)₂Cr₂(OH)₂(nta)₂·nH₂O, where M = Mn²⁺, Co²⁺, Ni²⁺ and Zn²⁺; bpy = α,α′- bipyridine; n = 8 or 9. Their chemical composition has been determined from the results of the elemental analysis and thermogravimetric study. The coordination modes of the nta3 ̄ ligand and the type of chemical bonds have been proposed basing on IR spectra.


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