Vietnam Journal of Chemistry

Silver/polyvinylalcohol nanocomposites are prepared via in situ reduction of silver salt by reducing agent – hydrazine hydrate (HH) and sodium citrate was used as supportive distribution agent. The solutions and the films are characterized by using UV-Vis, XRD and TEM. XRD patterns are consistent with that for cubic silver. TEM of the nanocomposite film shows particles distribution and size within the film.

All calculations were performed at the high level of theory (MP2/6-311++G(d,p)). Five separate minima were identified on the potential energy surface of each complex pairing CH3X with HNO. In general, strength of complexes increases in going from F to Cl to Br, which is consistent with respective decrease of deprotonation enthalpy of the C-H bond respectively. All the C-H and N-H bonds are shortened upon complexation, corresponding to increase in their stretching frequencies. It is interesting that blue shift is observed in the N-H bonds; such a contraction in the N-H covalent bond is extremely rare. Linear correlation between change of stretching frequencies and change of the N-H and C-H bond lengths in all complexes has been reported in equation (1) and (2). Besides, the change of the N-H bond lengths and their stretching frequencies as a function of the change of occupation of σ*(N-H) orbitals and that of s-character of N hybrid orbitals were obtained as in expression (3) and (4).

Anodic aluminium oxide (AAO) membrane has uniform parallel pores and high pore density. The pore diameter is controllable according to practical needs. Ag nanowires have been produced by Aternating Current (AC) electrodeposition in porous AAO template. So nanocompozit films consisting of regularly ordere Ag nanowires embedded in AAO templates. The composition and nanostructures of meterial was determined by SEM, XRD, EDX methods. The results of studying have showed nanocomposite Ag/Al2O3 demonstrated a stronger antibactericial activity than Al2O3 in air and water.

The paper deals with studying on the ability of docking urea on nitrogen base groups of DNA by Semi-Quantum Relaxation method. The structural clusters were defined and the lengths of hydrogen bonds were calculated. The places in nitrogen base groups where urea molecule could form hydrogen bond being the same ones in double helix which are in a good very agreement with the references. It is proving that the algorithm was used is suitable and it will be extended to study different ligands. Introducing the studied method about the clusters were created by docking small molecules on the defined groups of macromolecules, which could not be studied successfully by cluster approximation on Gaussian or Gamess software.

By cyclization reaction of 2,5-dihydroxyacetophenone with ethyl acetoacetate to get 3-acetyl-6-hydroxy-4-methylcoumarin). The product was then transformed by condensation with aromatic aldehydes to form a series of new α,β-unsaturated ketones (6 compounds) and (4-arylvinyl-6-hydroxycoumarin-3-yl) arylvinyl ketones (4 compounds) and (6-hydroxy-4-methylcoumarin-3-yl) (2,3-dihydrobenzofur-2-yl) ketone. Structure of the obtained products was determined by IR, 1H-NMR, and MS spectroscopic data.

The influence of the content of cationic photoinitiator–triarylsulfonium salt (TAS) on the photocrosslinking of the systems containing glyxydyl ete of o-crezolformaldehyde resine (CG), biscycloaliphatic diepoxy monome (BCDE) with the mass ratio CG/BCDE = 1/1 has been studied. The study of the photopolymerization of the epoxy group in the 20 mm thickness film of the system by IR – Spectroscopy in the presence of TAS in the range from 1% to 7% of the total mass of the CG and BCDE showed the fastest convertion rate of the TAS and epoxy groups at the content of TAS 5%, leading to the final convertion of TAS, epoxy groups of BCDE and the total epoxy groups of CG and BCDE 99%, 98% and 82%  respectively after exposure under 250 mW/cm2 intensity UV – lamp.

At the present, in order to increase octan number the izomerization of hydrocarbon has been studied in the world. Amongs metals and metal oxides on carriers, Pt on the alumina carrier is used most widely owing to the advantages such as thermal stability, high activity and high selectivity etc. The conversion and selectivity of the izomerization depend on the catalysts (the composition of the catalysts, the structure of the carriers, the distribution of metal, the acidity, the catalytic activity of the catalysts) and the reaction condition (temperature, volume flow, carrier gases ...).

The influence of some plasticizers such as cashew nut shell oil (CNSO), castor oil (CO), epoxidized soya–bean oil (ESBO) and diocthylphtalat (DOP)  on the photocrosslinking of the photocrosslinkable systems on the base of glycydyl eter of o–crezolformaldehyde resin (CG), Biscycloaliphatic diepoxy (BCDE) monomer, triarylsulfonium salt (TAS) have been studied. In the systems, the content of the plasticizers were 15% of the total mass of CG, BCDE and the content of TAS was 5% of the total mass of CG, BCDE, plasticizer. The mass ratio CG/BCDE was 60/40 and 40/60 for the systems containing CNSO, CO, DOP and ESBO respectively. During photocrosslinking of the 20 mm thickness film of the systems under 250 mW/cm2 intensity UV–lamp, the fastest rate of conversion and the highest final conversion of TAS were observed in the system without plasticizers, while the fastest rate of conversion and the highest final conversion of epoxy groups were observed in the system with the presence of CO. The obtained results were explained by the difference of the chemical structure of the plasticizers which influenced on the polarity of the photocrosslinking systems.

Ten aryloxyacetylhydrazones of carvone have been synthesized. Their structures have been confirmed by IR, 1H-NMR, 13C-NMR, DEPT and mass spectra. The spectral data has been investigated.

In this work, we have studied the duplex coating on carbon steel (steel/Zn-Al/(epoxy+CP)), in which the epoxies used are E828 and X75 and the CP is the conducting polymers of Ppy, Ppy/Fe2O3 and Ppy/Fe3O4, for protection against corrosion of the metal. The results obtained by electrochemical impedance show the galvanic protection effect of Zn-Al alloy and the influence of the epoxy coatings, which delay the penetrability of electrolyte and reduce galvanic dissolution of Zn-Al alloy, so the protective effiency will be improved. Among these conducting polymers, the Ppy without oxides who give the best protection resultal disperses well in both E828 and X75 epoxies to form homogenous coatings.