ANTIMICROBIAL ACTIVITY OF COPOLYMERS OF 2,4-DICHLOROPHENYL ACRYLATE WITH STYRENE:SYNTHESIS,CHARACTERIZATION AND REACTIVITY RATIOS

Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR spectroscopy.The copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods.Average molecular weight,as well as intrinsic viscosity,was obtained by vapor pre...     

Evaluation of the thermodynamic parameters for association process of hydrogen bond complexes from the dielectric relaxation measurements.

A relation between the free energy for dipole relaxation process and that for the association process has been proposed. Using this relation, an equation has been defined for evaluating the association equilibrium constant from the dielectric relaxation measurements. These equations have been applied to study the association of dimethyl sulphoxide and p-tolyl sulphoxide with proton donors (phenol and O-cresol) in an inert solvent carbon-tetra-chloride in the temperature range 298–322K. The calculation of the association equilibrium constant and hence the thermodynamic parameters have shown the wide scope, the proposed relations can be put to in the study of the association process of hydrogen bond complexes.     

Spike effects in heavy-ion sputtering of Ag,Au and Pt thin films

Sputtering yields of Ag, Au and Pt have been measured for monatomic and polyatomic ions of P, As, Sb and Bi over the energy range 10–250 keV. Large enhancements of the measured sputtering yields over those predicted by cascade theory occur for the very heavy ion bombardments. These enhancements become much larger for polyatomic ion bombardment and are strongly non-linear with the number of atoms comprising the molecule. The high sputtering yields are consistent with a major contribution due to a highly disrupted surface region and an associated reduction in the surface binding energy. They cannot be explained using a thermal spike model in which the enhancement results from a localized evaporation.     

An efficient fourth order weighted-Newton method for systems of nonlinear equations

In this paper, we develop a fourth order method for solving the systems of nonlinear equations. The algorithm is composed of two weighted-Newton steps and requires the information of one function and two first Fréchet derivatives. Therefore, for a system of n equations, per iteration it uses n?+?2n ² evaluations. Computational efficiency is compared with Newton’s method and some other recently published methods. Numerical tests are performed, which confirm the theoretical results. From the comparison with known methods it is observed that present method shows good stability and robustness.     

Synthesis,spectroscopic and X-ray structural study of [<Emphasis Type="Italic">trans</Emphasis>-di(4-aminobenzoato)bis(ethylenediamine) cobalt(III)] 4-aminobenzoate tetrahydrate

The title compound was synthesized by mixing the separately dissolved trans-dichlorobis(ethylenediamine)cobalt(III) chloride and sodium 4-aminobenzoate in aqueous medium in 1:3 molar ratio and recrystallizing the product obtained, from hot water. Elemental analyses and spectroscopic techniques (IR, UV/visible, ¹H and ¹³C NMR) were used for characterizing the complex salt. X-ray structure determination revealed an ionic structure consisting of [Co(en)₂(C₇H₆NO₂)₂]⁺ cation, (C₇H₆NO₂)⁻ anion and four lattice water molecules. The complex salt crystallizes in the triclinic space group P with cell dimensions a = 9.985(1) Å, b = 11.522(1) Å, c = 14.233(1) Å, α = 80.20(1)^∘, β = 72.80(1)^∘, γ = 86.43(1)^∘, Z = 2, V = 1541.3(2) ų, R₁ = 0.0291, and wR₂ = 0.0751.     

Synthesis,characterization and single crystal x-ray analysis of a complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine

Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [{(2,4- (CH₃)₂C₆H₃O)2PS2}2Fe{NC₅H₄(C₂H₅)-4}₂] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P2₁/n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry.     

X-ray crystallography of methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4<Emphasis Type="Italic">H</Emphasis>-pyran)-3-carboxylate

The organic carbonitrile namely methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4H-pyran)- 3-carboxylate is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst and its crystal structure is determined by X-ray technique. The crystals are monoclinic, sp. gr. C2/c, a = 12.3069(8) Å, b = 9.7023(7) Å, c = 24.812(2) Å, β = 94.862(6)°, Z = 8. The dihedral angle between pyran and phenyl rings is 87.8(1)°; the pyran ring is almost planar The dihedral angle between the mean planes of phenyl ring and nitro group is 44.4(2)°. The crystal structure is stabilized by N?H···N and N?H···O hydrogen bonds. In addition, C?H···π interactions are also observed in the crystal structure.     

Selective detection of bismuth(III) and iron(II) ions with certain new reagents

Isoperthiocyanic acid (3-amino-5-thione-1,2,4-dithiazole) (I), tetraethylthiuram monosulphide ("Tetmosol") (II), eosin (III), and mercurochrome (IV) are used as new qualitative reagents for bismuth, III and IV are also used for detection of iron(II). A conc. sulphuric acid solution of I, or an acctone solution of II, when treated with bismuth in presence of potassium iodide, gives a deep red or reddish-orange precipitate, characteristic of bismuth. Bismuth in presence of III or IV gives a heavy and characteristically bright deeppink precipitate on addition of ammonia. With I, 1 mug of bismuth may be detected with a dilution limit of 1:50,000. Sb(III) and As(III) do not interfere in any of these tests. Iodides interfere only when I and II are used as reagents. Pb, Cu(II). and Fe(III) interfere with III and IV. I and II are also proposed as reagents for iodide; nitrites would interfere. III and IV, with iron(II) on addition of ammonia, produce a precipitate with highly intense green fluorescence. No other common cation [including Fe(III)] or anion interferes. The limit of detection is 3 mug ml .