THE NATURE OF THE Co-C BOND CLEAVAGE PROCESSES IN METHYLCOB(II)ALAMIN AND ADENOSYLCOB(III)ALAMIN

The research results have marked a low value of the self-purification capacity for Beleu Lake water, between 0.12 and 0.19, which is of 1.2-2 times smaller than the one from Prut River (0.25), correlating positively with the values of BOD5, COD-Cr and the time of biochemical oxidation of ammonium ions. The evolution of stage NH4(NH3) NO2 in the process of nitrification in lake water in November 2014 takes place about 25 days and the process NO2 NO3 more than 35 days, the duration about 2 times higher than in lake water stages from 2015 and 2.8-3.0 times higher than that of the model with water from Prut River.

The research results have marked a low value of the self-purification capacity for Beleu Lake water, between 0.12 and 0.19, which is of 1.2-2 times smaller than the one from Prut River (0.25), correlating positively with the values of BOD 5 , COD-Cr and the time of biochemical oxidation of ammonium ions. The evolution of stage NH 4 + (NH 3 ) NO 2 in the process of nitrification in lake water in November 2014 takes place about 25 days and the process NO 2 -NO 3 --more than 35 days, the duration about 2 times higher than in lake water stages from 2015 and 2.8-3.0 times higher than that of the model with water from Prut River.

Larisa Postolachi, Vasile Rusu, Tudor Lupascu
Aluminium sulphate is one of the most widely used coagulants for water treatment and has been proven to be an effective coagulant for the removal of certain contaminants, turbidity and colour. Aluminium sulphate used during the coagulation process is hydrolyzed in the water, forming polynuclear complexes. Aged aluminium solutions show different coagulation behaviour than that of freshly prepared solutions. Obtained results reveal that using of optimal aging solution of coagulant improves the coagulation process.

THE FORMATION MECHANISM OF ASSEMBLED COMPLEXES BRIDGED BY 1,3-BIS(4-PYRIDYL)PROPANE
The spectroscopic and structural characterisation as well as their biological, properties are presented.

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NATURAL PRODUCT CHEMISTRY AND SYNTHESIS 50 This study describes the synthesis of some novel compounds containing bis-1,3,4-oxadiazole bearing quaternary ammonium salt moieties. The newly synthesized compounds were evaluated for their antibacterial activity against various gram-positive and gram-negative strains of bacteria, and the antifungal activities were tested against three phytopathogenic fungi namely, Fusarium oxysporum, Fusarium commune and Fusarium rodelens.

STUDIES OF THE SUBSTITUTION EFFECTS ON THE ELECTRONIC PROPERTIES FOR BIPHENYL AND DERIVATIVE MOLECULES BY USING DFT METHOD
Rajaa Khedir Al-Yasari DFT method has been carried out to study the substitution effects of NO 2 group on the electronic (ionization potential, electron affinity, electronegativity, hardness, softness and electrophilicity index) and IR spectral properties of biphenyl and derivative molecules by using the B3LYP functional and the 3-21G basis set, as well as the optimization structure. The calculated values of HOMO and LUMO energies, as well as predicted by ChemBioDraw program 1 H and 13 C NMR spectra for the studied compounds are in a good agreement with experimental data.

Sharali Malik, Ian James Hewitt, Annie Katherine Powell
We have synthesized a variety of magnetite nanoparticles which appear to have biogenic signatures and could give insights into how the nanomagnetite particles form in biological systems, and how they are associated with Alzheimer's disease. We have also synthesized mesoporous magnetite nanoparticles which have potential use in the targeted drug delivery.

DFT (B3LYP) COMPUTATIONAL STUDY ON THE MECHANISMS OF FORMATION OF SOME SEMICARBAZONES
Abdulfatai Siaka, Adamu Uzairu, Sulaiman Idris, Hamza Abba Thermodynamic and kinetic mechanisms of forming six semicarbazones have been investigated computationally by DFT B3LYP method. All the reactions proceed via two transitions and include two consecutive steps: bimolecular and unimolecular. The computed transition steps have varying equilibrium constants values, enthalpy of activation and Gibbs energy of activation, depending on the semicarbazone involved. Planar organic heterostructures were prepared using poly-Nepoxypropylcarbazole films and poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4phenylenevinylene] by the method of successive deposition adding 2, 3,9,10,16,17,23,24-zinc octabutylphthalocyanine. Photoelectric, photodielectric and photovoltaic properties of the heterostructures were studied.

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PHYSICAL CHEMISTRY AND CHEMICAL PHYSICS 91 Phase state and the charge of colloidal particles in the gelatine-polyuronate system were studied. A method for comparative evaluation of molecular weight of colloids by means of viscosimetric measurements and electrophoresis was developed. It is shown that the Diagram {Phase state = f (composition, pH)} contains six well-defined regions. The diagram explains and predicts the behaviour of protein-polysaccharide colloids, which are included in beverages or forms the shells of oil-containing microcapsules.