Chemistry Journal of Moldova. General, Industrial and Ecological Chemistry

8-20

Authors: Andrei Rija, Eduard Coropceanu

A comparative study of the orientation of the axial ligands relative to the equatorial plane in Co(III) α-dioximates was performed. Co(III) α-dioximates obtained by us and those founded in Cambridge data base have been selected for this study. As a result of this study it was observed that anions from the external sphere and the solvent molecules contribute to the orientation of the axial ligands, such as thiocarbamide and selenourea. For the ligands such as aniline and sulfanilamide it is more advantageous the almost parallel orientation, when π-π interactions between the aromatic rings of the ligand and metallocycle of the equatorial plane are formed. Solvent molecules such as water can be found in the crystal structure in the vicinity of thiocarbamide and selenourea ligands, which are oriented parallel to the equatorial plane. In the case when diphenylglyoxime is located in the equatorial plane, water can be found in the vicinity of parallel and perpendicularly oriented ligands. The molecules within the crystal are arranged so closely that there are no gaps in the crystal lattice of these compounds.

32-41

Authors: Lilia Anghel, Gheorghe Duca

Iron-based nanoparticles have gained a lot of attention due to their properties which offer a broad range of biomedical and industrial applications. Traditional methods of synthesis of iron nanoparticles strongly influence their properties and limit their applicability. Recently, there has been a growing interest in the development of biological routes of syntheses of iron nanoparticles as the resulting particles have structural characteristics required by biomedical field. The mechanism for the synthesis of iron-based nanoparticles by microorganisms and its current limitation are presented.

51-56

Authors: Larisa Postolachi

Bottom sediments of the river are repositories for various elements, acting both as sinks and sources of supplying of elements to overlying water horizon. Re-suspension of the bottom sediments of the Prut River was performed in field conditions by „aquarium” method. The results suggest that during the re-suspension, bottom sediments can become a relevant source of heavy metals and phosphorus forms which are mobilized in the water horizon overlying the bottom sediments.

67-72

Authors: Igor Povar, Oxana Spinu

The key quantitative characteristics of the theory of buffer action for polycomponent mono- and twophase systems have been derived. It is shown, that the buffer properties in relation to the solid phase components are amplified with an increase of solubility due to protolytic or complex formation equilibria in saturated solutions. It has been established, that the buffer capacities of components are mutually proportional, whereas for heterogeneous systems these relationships depend on the stoichiometric composition of solid phases. The deduced equations can be applied to the assessment of buffer action of the systems “natural mineral – soil solution”, containing soluble and insoluble chemical species. A number of the important conclusions concerning the investigated buffer systems have been made. The obtained results are of interest for soil scientists and ecologists.

78-82

Authors: Carolina Vomisescu, Paulina Bourosh, Victor Kravtsov, Diana Dragancea

Reaction of 2-hydroxy-3-methoxybenzaldehyde semicarbazone with Ni(NO3)2·6H2O, in the presence of 2,2’-bipyridine, afforded a dinuclear complex (1). Crystal structure of 1 revealed the dinuclear complex, in which one nickel center is surrounded octahedrally by two monoanionic O,N,O-donor semicarbazone. The second nickel center also adopts an octahedral geometry created by two 2,2’-bipyridine ligands and the bridging phenolate oxygen of the monodeprotonated semicarbazones.

90-93

Authors: Olga Morarescu, Marina Grinco, Ion Dragalin, Veaceslav Kulciţki, Nicon Ungur

The content of known tetra- and pentacyclic diterpenoids in extracts of sunfl ower (Helianthus annuus L.) dry wastes has been studied using different solvents for extraction. It was established that the largest extracted quantity of ent-kaur-16-en-19-oic acid is obtained when ethanol and diethyl ether are used for extraction of the plant material.

101-106

Authors: Ramin Rezaei, Sara Malek, Mohammad Reza Sheikhi, Mohammad Kazem Mohammadi

The one-pot multicomponent synthesis of 3,4-dihydropyrimidinone derivatives using starch sulfuric acid as an environmentally friendly biopolymer-based solid acid catalyst from aldehydes, β-keto esters and urea/ thiourea without solvent is described. Compared with classical Biginelli reaction conditions, this new method has the advantage of minimizing the cost operational hazards and environmental pollution, good yields, shorter reaction times and simple work-up.

6-13

Authors: Irina Shugalei, Mikhail Ilyushin, Veronika Sokolova, Nadejda Dubjago, Irina Bachurina, Alexander Garabadzhiu

The present article provides route of synthesis of complex copper compounds with 1.5-pentamethyltetrazole as a ligand. These compounds are considered promising antioxidants that can fi nd application in treatment and prevention of “free radical” conditions caused by a variety of reasons, e.g. harmful environmental factors. The obtained compounds were rated by their antioxidant potential; the ability to inhibit lipid peroxidation and SOD-like activity thereof were assessed by independent experimental techniques.

23-32

Authors: Viorica Gladchi, Gheorghe Duca, Nelli Goreaceva, Elena Bunduchi, Angela Lis

This article presents the results obtained in the framework of the project 09.832.08.06A The role of the tributaries on formation of the Dniester river water and the study of the waters quality of sources/fountains in the catchment area of the Dniester river as sources of water supply and for irrigation in the State Program, Scientific Researches and of the management of waters quality.

43-46

Authors: G. Torosyan, Ghazi Aidan, N. Torosyan

Phase-Transfer Catalysis (PTC) technology is used in commercial manufacture. PTC is used also in pollution treatment processes. In the paper the synthesis of esters of acrylic, metacrylic acids, which have wide industrial application for production of unique polymeric materials, by phase transfer catalysis method is demonstrated / PTC/. It is necessary to notice, that the synthesis of acrylic acids through PTC is more important because these compounds are more sensitive to acidic and basic conditions. PTC is characterized by a high degree of useful use of substances involved in reaction, smaller consumption of materials and power resources. The work is devoted to technological problems of the synthesis of ethers in the aspect of environment’s protection. The offered method for acrylic ester synthesis, in comparison with the traditional methods, has more advantages including high speed of process, soft condition of reaction allowing reduction of energy expenses, the complete exception of application of hazardous and dangerous organic solvents, by virtue of its sharp reduction of air pollution and reduction of wastewater effluent.

58-77

Authors: Vasile Lozan

A series of novel tri-, tetra- and pentanuclear complexes composed of dinuclear LM2 units (M=Co, Ni, Zn; L=24-membered macrocyclic hexaaza-dithiophenolate ligand) and ferrocene-carboxylate ([CpFeC5H4CO2]ˉ), 1,1’-ferro-cenedicarboxylate([Fe(C5H4-CO2)2]2ˉ), acetylenedicarboxylate, terephthalate, isophthalate, and naphthalene diimide dicar-boxylate groups is reported. The complexes have been synthesized and characterised by UV/Vis-, IR-spectroscopy, and X-ray crystallography. Each dicarboxylate dianion acts as a quadridentate bridging ligand linking two bioctahedral LM2 units via μ1,3-bridging carboxylate functions to generate discrete dications with a central LM2(O2C-R-CO2)M2L core.

83-89

Authors: Popusoi Ana, Barba Nicanor, Gulea Aurelian, Roy Jenny, Poirier Donald, Prisacari Viorel

This paper describe the synthesis of some 1-(alchyl)aril-3-(4-(3-pyridin-2-il) acryloyl)phenylthiourea obtained by condensation of 2-pyridincarboxaldehide with some derivatives of 4-acetylphenilthioureas in basic medium or by addition of aliphatic and aromatic amines to the correspondingisothiocyanatopropenones. 12 new compounds were obtained and their biological properties were analysed. The substituted thioureas by pyridine radicals, morpholine and phenol show a maximum bacteriostatic activity for Gram positive microorganisms like: Staphylococcus Aureus and Enterococcus Faecalis at the minimum inhibitory concentration 9.37-37.5 μM. Antifungal activity for Candida Albicans, Aspergillus Niger, AspergillusFumigatus, Penicillium is weak, in minimum inhibitory concentration 600->600 μM. The leukemia activity like inhibitor (HL-60), is 84-96.9% at the concentration 10-5mol/l and 15- 20% and at the concentrations 10-6, 10-7mol/l.

95-100

Authors: O.G. Kolumbin, L.N. Ognichenko, A.G. Artemenko, P.G. Polischuk, М.A. Kulinsky, Е.N. Мuratov, V.E. Kuz’min, V.A. Bobeica

In our study the dataset containing 489 pesticides and their active substances of different classes of organic compounds was used for analysis. For compounds of analyzed dataset the values of lipophilicity, water solubility, toxicity, bioavailability and mutagenicity were predicted by developed QSAR models. The most environmentally hazardous substances were identified using prediction of QSAR models for pesticides. The satisfactory coincidence between the experimental values of investigated properties and their predicted values by QSAR models was obtained (coefficient of determination in the range 83-94%).